Radiation Safety and Shielding
Radiation Safety and Shielding NE 404
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RA DIA TI ON SA FE TY and SHIELDIN G 355304 0 Fall 2008 Radiation Sources lt e Gerald Wicks CHP Objectives 0 Characterize sources of radiation and radioactivity from Nuclear fission Activation 0 Describe sources of radiation and radioactivity from Medicine Industry Nature 0 Determine appropriate photon energy groupings for a complex source term RADIATION SOURCES 0 Nuclear Reactions Nuclear fission prompt radiation Accelerators particles photons Neutron sources eg dn PuBe yn Na24Be spontaneous fission Cf 252 delayed neutrons o Radioactive materials Byproduct materials from nuclear fission or activation Naturally occurring radioactive materials NORM Technology Enhanced NORM TENORM Source material fissile material special nuclear material 0 Radiation producing devices Xray machines Accelerators Contribution of Various Sources of 39 Radiation to Average Annual Dose Medical X R Nuclear a s o o 11 y fdlcme Consumer Internal 0 Products 3 11 Other 1lt1 Occupational 03 Terrestrial Fallout lt03 8 Nuclear Fuel Cycle 01 Miscellaneous 01 Cosmic 8 360 mremy 80 natural 20 manmade Radon 55 Notes on Average Annual Doses 0 Medical Dose Number of medical exams is increasing Number of higher dose medical exams is increasing eg CT fluoroscopy digital radiography Doses are averaged for entire population patient doses are much higher Dose to public is controlled by shielding xray shielding radiation therapy rooms hospitalizing patients with radioactive implants OR limiting time and distance for visitors if not hospitalized o Radon Dose Weighted doseequivalent to the respiratory tract or effective dose equivalent is reported as 200 mremy Respiratory tract dose is 8 times higher 1012 Assumptions are made regarding time concentration age sex for determination of dose from radon Radiation Sources 0 External Exposure OR Potential Contamination leading to Internal Exposure from other sources including Radioactive waste disposal Radioactive effluent ie environmental releases Radioactive package transport 0 httpwwwepaqovradiationsourcesindex html Radioactivity o Radioactivity is defined as the spontaneous disintegration of unstable nuclei with the resulting emission of radiation that results in the formation of new nuclei 0 As a nuclide departs from the line of stability changes in the nucleus occur which tend to bring the product to a more stable arrangement This approach to stability is accomplished by one or more modes of radioactive decay Radioactive Decay Modes Alpha Particle He nucleus tunnels out of nucleus discrete energy Beta Minus Particle Neutron decays to proton beta minus particle electron and antineutrino beta particle has energy up to a maximum value Beta Plus Particle Proton decays to neutron beta plus particle positively charged electron and neutrino positron has energy up to a maximum value Electron Capture Atomic electron is captured by nucleus and combines with a proton to form a neutron lsomeric Transition The nucleus is reconfigured to a lower energy state with the emission of a gamma photon no change occurs to the number of protons or number of neutrons Spontaneous Fission Nucleus undergoes fission heavy elements Delayed Neutron Emission A few fission products undergo decay and emit neutrons All of the above may produce gamma rays and xrays 0 Radiation Types Alpha Beta Photons Neutron Proton He nucleus charge of 2 Electron charge of 1 or 1 Electromagnetic radiation Xrays come from deexcitation of electrons and are atomic in origin while gamma rays come from deexcitation of the nucleus and are nuclear in origin no charge no mass Neutral particle Particle with charge of 1 or H nucleus Fission fragments and recoil atoms are charged atoms Mesons are charged particles with 270 X mass of electron OTHER RADIATION TYPES o Other types of radiation occur as a result of the release of particles and photons or radiation interactions or nuclear reactions Annihilation photons Conversion electrons Auger electrons Characteristic xrays Bremsstrahlung xrays Prompt neutrons Prompt gamma rays Xray Production 0 ELECTRON Target Nucleus XRAYS Tungsten BREMSSTRAHLUNG Yield 6E4EZ1 6E4EZ XRAYS O CHARACTERISTIC C Radioactive Decay Equation AAN A dNdt dNdt N A 0693IT12 dNdt N A A 0 e 39M Where A0 Initial Activity A ACTIVITY AT TIME T 0 39 Decay Chain Consider the following batch decay sham MAW N3AgtN5 Stable nuclide T wv r hain quot 39 39 The ne rate of change of each nuclide In the decay chain is39 2444 dr The schnions m mese squamous are N1 N11 7 MN 4 A1 AliI 1 7 N3 J 2 v e A 1L123113M 7mm 11 armums M Nfu 757 7N2 N3 39mn a mammal Iamm Lu be general case of a radioactive decay chain N HN gtN34gtgtN14gtmgtIvjgt The amount ofN of any uuclide presem m mm can be Written by analogy if Vr00 N13 00 0 Mz1azv i 739gt1 1 m up Hm General Solution for Decay Chain This equation is known as me Bmemau equan39ou By superposition me batch decay equanon can be mm cuclmi u m 39 mm amoums N 01 nu 39 39 39 39 3 1 Equilibrium Secular equilibrium Parent half life greatly exceeds daughter half life 2 Transient equilibrium Parent half life exceeds daughter half life No equilibrium Parent half life is less than daughter half life omhlned acumy nrmlnzl mm nudme Escular new rmdu equlmnum nme gt 1 period or mgmwlh combined activity nriylnal mainnuume I data summer I x v may WM 0 lranstenlequmbrlum Angmwlh nrlglml rzdlnnu mine decry umuum acnvuy combined acllvlly l l mac or mgrle e l nn equlllbllum Co60 Decay Diagram 60Co 192528 d 5 an I1 2 me By decay mm mm Bgt quot1 39Vs 39Vn 50Nistable CoGO Decay Data EB endpoint keV IB Decay mode 31813 99925 20 3 66526 0022 3 149138 0057 20 3 E7 keV I39y Decay mode 34693 00076 3 82606 00076 3 1173237 999736 3 1332501 999856 3 215857 000111 3 2505 20E6 3 Activation and Fission Sources Neutron Activation prompt and delayed radiation Radiative Capture o The neutron is absorbed by the nucleus and one or more gamma rays called capture gamma rays or prompt gamma rays are emitted ny reaction 0 This is an exothermic interaction 0 Numerous photons up to several MeV may be emitted 0 Internet references for capture gamma photons httpwwwndsiaeaorqpqaa httpielblqovnqhtml Radiative Capture Incident neutron upun cupturc l39urms the cumpountl nucleus n X Ath r l bimlinz cncrgyis given to X r Neutan kinetic energy plus u l Excitation energy in typically several MeV I pon decay the enmpountl nucleus emits energetic photons mxt nr 39th W EX E 4 Ext 5 Capture pltotuns are n concern ltl rntliution alticltling u 39netttrons aylEl small for high neutmn energies 100 s M39mh fraction 0 39a at Ilgltnu n energ39 igxlilicttttt for thermal neutrons 1000 s Mb 111 Vnr l mc inn 0 0 1 lbr smncnuclirc To minimize this el39l39cct in shic l39e Sll1llCllVlll1 39B and quotLi are used tu take advantage ml the neon intemctinn for thermal neutm s E Neutron Capture Interactions of Interest Neutrons produce photons by the capture n33 and inelastic scattering nn interactions Gamma photons produced by inelastic scattering rarely affect radiation shield design Capture gamrm photons are produced primarily by thernnlized neutrons and often are of very high energy and therefore have a significant affect on shield design Refer to FaWampShultis Appendix D for capture photon data Other capture absorption interactions of signi cance H1 11 3 H 2 With photon energy of 222 MeV Li6 mi9 H 3 BlO n XLi 7 and Li 7n Li8 with photon energy of 0 48 MeV Neutron Activation Equation Delayed gamma emitters o A N c 1exp7 T exp t 0 Where A Activity Bequerels N number atoms of parent isotope l neutron flux ncm2sec o capture reaction cross section NOTE Resonance absorption peaks may significantly contribute to the activation process 7 decay constant ln 2 T12 T sample activation and t decay time o Neutron activation calculator Neutron Activation Calculator 0 Gamma spectra httpwwwinlqovqammaraycataloqscataloqsshtml 4 ar V s ISSIOI I m mu 1 w v radiative capture Time n O 00 00 O Reactor Fuel Activation products of fuel cladding components Prompt gamma Fission products contained within pellet and cladding some leakage may occur Shortlived Longerlived Capture gammas Gammas from neutron inelastic scattering Timedependent source term mm mm LDMWM ma mm mm 1w mm mm nu ms 10le mu 5mm IDH39DM mm mm smu Reactor Fuel Assembly Prompt Gamma Energy Spectrum 0 Energy Spectrum Equations NE 268 exp23E for 0ltElt1 MeV NE 8 exp1 1 E for 1ltElt8 MeV NE 67 exp105E 30 exp38E NE 20 exp178E for 06ltElt15 MeV NE 72 exp109 for 105ltElt105 MeV 0 Yield 10 photons per fission 3 photons per fission with average E of 017 MeV for E lt 03 MeV 7 photons per fission with average E of 1 MeV for E gt 03 MeV o F rompt gammas are emitted within 50 ns after the fission event Prompt Gamma Energy Spectrum 0 NE C expKE where E is energy in MeV NE is number of photons at energy E NEdE is number of photons in the interval between E and EdE C and K are fitting parameters 0 Average E Jab NEEdE Nab NEdE 0 Average E expKEKE1 ab K expKEgt Iba eg1lt E lt 8 Average E 0703 19 MeV for K 11 Fission Products Radioactive fission products of various halflives are produced following the fission process Many decay to other radioactive species resulting in very complicated time dependent patterns of radioactive decay 75 of equilibrium reached in 15 minutes so equilibrium is reached at 60 minutes Average fission product undergoes 3 beta decays before reaching a stable nuclear configuration For U235 684 MeV per fission Average Beta E 04 MeV B Gamma E 07 MeVy For other fissionable material Isotope Mev per fission U238 109 Th232 108 Pu239 615 U233 424 Activity and gamma spectra calculations are complex Estimates based on hundreds of radionuclides Detailed calculations are made with computer codes eg ORIGEN CINDER m Fission Products When uranium235 undergoes ss n A2116 235U Fission me Fragments BB 110 130 153 Max numbers at Minquot quotsz strontium90 are extremely dangerous when released to the environment Fission Fragment Decay eg This particular set of fragments from uranium235 ssi undergoes a series of beta decays to form stable end products Irvis 4 1w Sr xi 3 TNa 140 0 3 1645 I4 Eru p TIHd x 140 La 4quot T 40hr A3113 Q 235 1 Ca Bran U Fissmn Fragments 5 pg 175 1m max mmimn ssion quot341mm 94 m 179 Y Li T 19 Mn 95 Zr 5w 0 Fission Products Collective Activity Estimate per Fission Beta activity AB 38E6 t12 Bs perf Gamma activity AG 19E6 t12 ys perf Assume 1 Bd so AFP 38E6 t12 Bq perf or AFP 38E61 Ci 37E10 Bq t12 AFP 103E16 t12 Cif WHERE 10 s lt tlt few weeks eg 100 days Fission Products Collective Activity Estimate at Constant Power for Fixed Time of Operation T and Fixed Decay Time t Time scale T t IdS s dAFP 38E6 dpsf31 E16 fs per MW P 86400 sday ds 312 where P is power in MW and s time in days A 103 E16 P LT 312 ds A 51 E16 P tO2 Tt02 in Bq A 14E6 P tO2 Tt02 in Ci Fission Product Decay Energy Collective Decay Energy Estimate per Fission Decay energy EFF 04 MeVf38E6 T12 83 per f 07 MeVf19E6 T3912 ys per f EFF 28E6 T3912 MeVs perf Energy Distribution EB 38E60428E6 053 Beta energy EG 1 9E60728E6 047 Gamma energy Fission Product Decay Energy Collective Decay Energy Estimate per Fission Decay energy EFF 04 MeVf38E6 T12 83 per f 07 MeVf19E6 T3912 ys per f EFF 28E6 T3912 MeVs perf Energy Distribution EB 38E60428E6 053 Beta energy EG 1 9E6O728E6 047 Gamma energy Fission Product Decay Energy Collective Decay Energy Estimate at Constant Power for Fixed Time of Operation T and Decay Time t dEFP 28E6 MeVf31E16 fs per MW P 86400 sday ds s12 where P is power in MW and s time in days E 75E15 P itTt 312 ds E 37E16 P t39O2 Tt3902 in MeVs total E 2 E 16 P tO2 Tt02 in Beta MeVs E 17E16 P tO2 Tt02 in Gamma MeVs ShortLived Fission Product Gamma Energy Spectrum 0 NE 74 exp11 E where E is energy in MeV NE is number of photons at energy E NEdE is number of photons in the interval between E and EdE 0 Average E Jab NEEdE liab NEdE 0 Average E expKEKE1 ab K expltKEgt Iba eg 1lt E lt 8 Average E 07037 19 MeV Prompt Gamma PLUS ShortLived Fission Product Gamma Energy Spectrum Simply double the prompt gamma energy spectrum as a rough approximation similar yields and energy distribution NE 15 exp 11E 0 Other Gammas from Reactors o U235 nv U236 CC 98 b vs oF 585 b OR oC oF 017 80 1 capture for every 6 fissions Capture gamma energy is 63 MeV 63 MeVcapture017 capture fission 11 MeVf o Inelastic neutron scattering n n v Not significant for thermal reactors Significant for fast reactors 0 Transuranio Isotopes o U238 nv U239 o U239 beta decays to Np 239 o Np 239 beta decays to Pu239 0 Similar processes for isotopes of Am Cm Pu 0 Most transuranics are alpha emitters and therefore hazardous if released ShortLived Fission Products Gamma Energy Distribution r It is possible to take into account ssionproduct yields systematics of radioac tive decay chains and decay characteristics of individual ssion products and their progeny to calculate the gamma ray energy spectrum 5 a function of time after the ssion process As applied to nuclear reactor ssion products such a calculation may be enlarged to account for 1 the thermal energy released by the ssion products via both photon d b D quot re a e 2 L y 39 quot r during reactor operation prior to removal of fuel for storage processing or disposal 3 the nature ofthe fuel for example mixtures of 235U and 239Pu and 4 the type of reactor Lquot L J a Llluul of r 39 39 One wellknown computer code for accomplishing these objectives is the ORIGEN code a product of Oak Ridge National Laboratory Hermann and Westfall 1984 An England Wilczynski and Whittemote 1976 Neither code attempts to identify indi vidual gamma rays from ssion products Both use the energy multigroup approach LaBauve et al 1982 analyzed results of detailed calculations to derive an em pirical method which can be used quite successfully even with hand calculations to determine the energy spectra of gamma and x rays and beta particles and electrons from ssion products In 39 39 quot39 394 39 gamma quot 39 39 energy groups Then 15 seconds after an individual ssion the energy emission rate F3 MeV s in energy group j for t from 10 4 s to 10 9 s is expressed approxi mately as N2 FtZaJe5 Jl j lto 611 1 Values of on and B are given in Table 64 for all ssion products arising from thermal neutron induced ssion of 235U The same equation can be used to give the total en ergy release rate following a ssion for all gamma and x rays and all beta particles and electrons parameters for these release rates are also given in Table 64 Addi tional tables are available for ssion of 23Wu and too for gaseous ssion products exclusively and for beta particles LaBauve et a1 1982 uppose that a nuclear reactor has operated with a timedependent number of ssions per second Pft for time to prior to shutdown Suppose too that one may neglect transmutation of ssion products by neutron absorption generally a good assumption Then at time t after shutdown of the reactor the energy release rate MW 5quot by ssion product photons with energies in groupj is Ftt dtPItFJL30 1 612 a Form Pm 39 mum L this cxprcssion yiclds quot1 F100 P 2a5eBuh1 7 e to 513 1 The ssion rate P is related approximarely to thermal power by the factor Sr x 10m ssions per second per watt Figure 6 illustrates Fm for a single ssion and Fig 62 illustrates PJ ot for a unit ssion rare P l and for an operating lime to 30000 hours which is representative of fuel consumption in a nuclear power reactor a 39 Mn r v 1 1 L 39 m r 39 39 39 leading to an overestimate of gamma radialion from longlived radionuclides The reader will also note that in Eq 613 x may be set equal to zero thereby giving an 39 39 39 39 xmuw u um Iduldliol l emitted by the ssion products within the reactor fuel inquot Decay Margy Nevs w lrssmn Decay rm 5 Figure m A L r b Hum me me issron or my quot iu n vr m nw vi r L ranges 57 51 4 5 34 erEl 1 21 and 01 MeV Calcula nns based on the data cl ram 6 4p Decay energy Nev5 per flssmns Decay time 5 Figure 62 Calculated total gamma G and beta B energy emission rates as a function of time after the fission off235U for 30000 hours of a constant rate The curves identified by the numbers 1 to 6 are respec tively rates for photons in the energy ranges 545 4 5 3 4 2 3 12 and 0 1 MeV Calculations based on the data of Table 64 TABLE 64 Consmnls in the Empirical Approximation for Energy Release by All Fissmn Pmducls Arising from ThermalNeutron Induced Fission mi 13511 Table Entries Read as 93 1222E713 222 x inquot mmupzm2 13 GROUP4N4 13 GROUP N 9 momma3 14 s 34 MeV 6IEE 07 275315718 6788E 14 33515 08 562913 10 2787E713 271939E l7 8227E 11 93113 20 EDBEOE SDBEOl 2539E00 461 04 l 0 25345704 2204 2572E703 7 115701 2799E 03 2750E03 Z953EDO 3506E 03 35591570 GROUPG NC 11 ALL GAMMAS 13quot aij 28171371 7350E 1l 23055 11 7332E410 SIBBIE 4 l ZE Ol i LZSZE Ol 10531370 264E00 5222E00 5196E00 MINE ll 1721E 01 2754EDU Source LaEauve el al 1982 0 Fission Product Inventory M m Fission k Pt Yi Decay of precursors erj 1 ch Transmutation erj j i 5 M w m Radioactive decay JElNci Transmutation i 5 Nci Escape from fuel f Nci where k 31 E16 fissions s 1 per thermal MW Pt is power level in thermal MW at time t f is fraction of inventory in defective fuel is the escape rate coefficient c is core Activity A for a given radionuclide may be approximated as follows A dNdt formation rate removal rate dNdt ocpyN AN OR dNdt 31 E16 PY AN where 0 thermal neutron fission crosssection eg 585 E24 cm2 for U235 p the thermal neutron flux density in n cm2 s1 y the fission product cumulative yield ie chain yield N the number of atoms present in the target and is given by mass molecular wt x wt fraction x 6022 E23 A the decay constant of the radionuclide N the number of radioactive atoms present P is power in MW Y is fission product chain yield Solving for the activity at the end of irradiation time t or A0 gives the following N ocpyN 1 exp At A AO AN ocpyN 1 exp At AtT ocpyN 1 exp Atexp AT OR AtT 31 E16 PY 1 exp Atexp AT where t is the irradiation time T is the shut down time Fission Product Calculation Thermal neutron fission yields for the fission product chain may be used to account for the decay of precursors leading to the production of the fission product Including decay by precursors is conservative and for longer irradiation times is a good approximation to the correct cumulative yield Corrections for decay to daughter nuclides may also be made For example Atomic mass number 92 has a chain yield of 00603 Kr92 decays to Rb92 decays to Sr 92 decays to Y92 Kr92 yield is reported as 00187 or Kr92 yield Chain Yield yield for Rb92 Sr92 Y92 00603 00343 0 00073 00187 Rb92 yield 00187 00343 0053 Sr92 yield 00187 00343 0 0053 Y92 yield 00187 00343 0 00073 00603 0 BWR Fission Product Release Release rates are defined by the empirical relations I quotr A TEJ A EEYJJ t R l1mb ll I l i H I J u l where Ai release rate in Bqsec or pCis Ri release rate in fissions K a dimensional constant establishing the level of release b a dimensionless constant establishing the relative amount of each nuclide in a mixture of similar chemical group ie noble gas or iodine isotopes Yi fission yield of species i Ai decay constant of species i in s l By plotting log Ri versus log Ai for noble gases or iodine isotopes a theoretical straight line can be obtained with a characteristic slope of b 0 Fission Product Release It is convenient to characterize the release pattern or the composition of fission product mixture in three types as follows Release Value Release Characteristics of fuel defect and Pattern of b rate Ri activity release Recoil 0 K No defect activity release from tramp fuel proportional to reactor power Equilibrium 10 KATI Pin hole defect no consistent correlation of 1 release rate with reactor power Diffusion 05 mam5 Split cladding defect activity release changes exponentially with power 0 Barriers to release of fission products Fuel pellet and cladding Reactor coolant system Primary and secondary containment and associated engineering safety features RELEASE FATE hum sail W1 w Ezra a gm 2 1 2 quoti 1 1 Z Z Li a 1 gt n I y x t 1 151 g1c39 1quot 39 q 1 ll lll 39 Hawm39i a l l I 1 i I I I I I I I F v I I i quot I l I i 39 I x l I I i quoth I 39 39 39 H T n l 2 1 l 0 1 39 a I 5 nl g a H k 1 2 u z 0 x u 39 39l 39 39 1 1 m quot 1 m 3 1n 3 Figure 3 2 Typical Example of Log Release Rate vs Log Decay Constant for Noble Gases and Iodine Isotopes Radiochemistry in Nuclear Power Reactors 0 National Research Council Publication onIine readable text available at httpwwwnapeducataloqbhbrecor cl id9263toc Fission Products in Reactor Coolant o Fission products escape fuel and enter coolant 0 Removal of fission products from coolant occurs from clean up system and decay Leaking fission products in coolant quotWquot dNWi Nci 39 Nwi 39 Nwi f Nci t Jim kPYi Where it is the clean up rate constant Activation Products in Reactors Coolant activation products include 160 mp MN 2H 11 3H 180 10310181 41 A1 24Na 38C1 10B n3H 8Be 3 2He Xin PWR Radiolysis products of water H2 and 02 and ee radicals Corrosion activation products in coolant include CRUD Chalk River Unidenti ed Deposits from activation of materials Stainless steel Fe Zn Cu Cr Ni Co Mn Zircaloy Zr Sn Fe Cr Stellite Co 59C0 ma 60C0 64Zn nag sszn soCr mg 51 C1 5516 5916 54Mn 95213 58cc 69an 63Ni Transuranic TRU Activation products of 258U Very insoluble materials plate out on surfaces readily Pu isotopes 237 23 8 239 240 241 242 Am isotopes 241 242 Cm isotopes 241 242 243 Np isotopes 239 237 by decay of precursors BWR Source Terms Reactor water clean up system is used to maintain primary water chemistry by taking a small fraction of the primary ow 31905 and pumping it through a filterdemineralizer Processed water is returned to the primary coolant reactor through the reactor recirculation system Components include heat exchangers upstream of the filterdemineralizer pump either upstream or downstream of the filterdemineralizer and the filterdemineralizer All of these components and the piping is a source of activity Materials plate out on surfaces and accumulate in these components Components are usually in separate rooms in the reactor building ft clean up demin removal rate condensate demin removal rate Reactor water recirculation piping and pumps are signi cant source terms These components are located in the drywell Main steam lines piping tunnel and the turbine are significant radiation source terms due to quotcarry overquot of nuclides from the coolant into the main steam After leaving the high pressure turbine the steam is reheated by a small fraction of main steam prior to being injected into the low pressure turbine The turbine main steam lines and reheater rooms are a significant source term in the turbine building BWR Source Terms Condensate demineralizers are used in BWR to maintain primary water chemistry also These lterdemineralizers accumulate activity and become a signi cant source term in the turbine building BWR feedwater heaters use a small action of main steam to reheat condensate prior to return to the reactor Use of main steam makes feedwater reheaters a significant source term Offgases from the turbinecondenser contain noble gases some halogens and other non condensible gases H2 02 N2 e g These gases are rst held up for decay and then processed for exhaust to the atmosphere through an elevated stack Processing components include chillers HEPA lters charcoal columns and another bank of HEPA lters Delay lines lters and adsorbers are signi cant source terms Other systemscomponents which are radiation source terms Spent fuel and items in spent fuel pool Spent fuel pool clean up system lters pumps Reactor vessel components Various secondary systems from tube leakage Decay Shutdown or Residual Heat Removal Reactor power instrumentation Emergency Core Cooling Systems Liquid waste treatment streams sludge resin bottoms ti PWR Source Terms Reactor internals Steam generators Recirculation system Let Down System is used to maintain water chemistry and to remove radioactive materials Coolant is passed through Demineralizer and enters Chemical amp Volume Control System tank CVC S Off gases om CVCS go to Decay Tanks Gases from Recombiner go to Decay Tanks Liquids om Recombiner go to Condenser Condensate retums to CVCS storage tank Decay tanks may be vented through lters and discharged to atmoshpere through an elevated stack Secondary System quotcleanquot side of steam generators are blown down may contain radioactive materials due to small leaks Blowdown water is passed through demineralizers andor mixed with condensate before being discharged NUCLEAR POWER AIRBORNE RELEASES Noble gases isotopes of Kr and Xe Iodine vaporsgases 13111321 1331 13411351 Air activation products 41Ar Treatment Decay ltration and dilution NUCLEAR POWER LIOUID RELEASES a High purity low conductivity Low purity high conductivity Detergents Treatment Decay ltration amp demineralization or evaporation concentration and dilution Zero discharge policy Recycle water for reuse NUCLEAR POWER SOLID WASTES LLVW Spent Resins Evaporator Bottoms Concentrate Filter Sludge from liquid e luent treatment Irradiated components Dry Active Waste NUCLEAR POWER REACTOR ACCIDENTS Alternative source term AST for reactor cores are available om Regulatory Guide 1183 and NUREG 1465 available at wwwnrcgov Reactor Accident Sources NUREG 1465 Reg Guide 1183 Fer eurrently licensed plants the ehereete eties ef the fissien product release from the cure inte the eentehtment are set ferth in Regulate Guides 13 and 14 Refs 23 and have been derived frem the 1962 report DMM Ref 4 This release consists of 1W ef the eere inventew of noble gases and 50 of the iodines halfof which are assumed te deposit an interim surfaces very rapidty 39These values were based largety en experiments permmed in the late 19505 Evolving heated irradiated U0 pellets TIE14544 also included 1 of the remehthtg selid ssien products quotbut these were chapped frem eensi deletien in Regu tatery Guides 13 and 14 The 1 at t the selid seien products are eensidered in certain areas such as equipment qee39tifieetien Reactor Accident Sources NUREG 1465 Reg Guide 1183 SDHFCB term estimates under severe accident cettditiette became a great interest sher1215f alter the ThreeMile Island WI accident when it was nhsewed that may relatively small amounts ef iodine were released to the envirenment cantilevered with the emeunt predicted te be released in licensing calculations This led a number of observers to claim that severe aceident releases were much newer than pretrialst estimated The accident eeuree terms previded in this report are not considered applicable to reeeter designs that are very different rem LWS such as high temperature gasmelted reactors or liquid metal reactors Regulatory Guide 1183 Table l BWR Core Inventory Fraction Released Into Containment G quotP Release Group Phase Noble Gases 005 Ha ogens 005 Alkali Metals 005 Tellni11n Metals 000 Ba Sr 00 Noble Metals 000 Cerium Group 0 00 Lamhanidei 00 E 1 y I r Phase Total Table 2 WR Core Inventory Fraction Released Into C quotP Release Group Phase Noble Gases 005 Halozeus 005 Alkali Metals 005 Tellurium Metals 000 Ba S 39 0 00 1 Noble Metals 000 Cerium Group 000 Lanthanides 000 ontainment m39 V Inwessel Phase am 095 10 035 04 025 03 005 005 002 002 00025 00025 00005 00005 00002 0 0002 Regulatory Guide 1183 NonLOCA Fraction of Fission Product Inventory in Gap Group H 3 1 K139 S 5 Other Noble Gases Other Halogen Alkali Metals F rar 012 tion The Islease Bastions listed he a bunmp up m 2000 MWDMTL a air man v Toh 39v miahl Pm me BWR rod 3 ACCIDENT SOURCE TERVI This section provides an AST that is acceptable to the NRC staff The data in Regulatory Positions 32 through 3 re fundamental to the de nition of an AST Once approved the AST assumptions or parameters speci ed in these positions become part of the facility s design basis 39 D i c trust be evaluated against Regulatory Position 2 After the NRC staff has approved art implementation of an AST subsequent changes to the AST Will require NRC staff review under 10 CFR 5067 U Q E 3 t2 9 7 54 w 31 Fission Product Inventory 1 inventory 39 39 39n the r o 39 aquot l a tailahl for release to the containment should be based on the maximum full power operation of the core with as a minimum current licensed values for fuel enrichment fuel hurnup and an assumed core power tre current licensed rated thermal power times the ECCS evaluation uncertaintyS The period ot irradiation should be of suf cient duration to allow the activity of dosesigni cant quot i nuiltlrritmt or m rea a 39imum Values T39 39 a determined using an approprrate isotope generation and depletion computer code such as ORIGEN 2 Ref 17 or ORIGENARP Ref 18 Core inventory factors CiMWt provided in TDl4844 and used in some analysts computer codes Vt ere derived for low burnup lou em39ichnrent fuel and should not he used with higher hurnup and higher enrichment fuels v V r m CFRPanSO rvplcally r 02 n t Carl Thus the maximum tax emery a the end of life should be used For the DBA LOCA all fuel assemblies in the core are assumed to be affected and the core average inventory should be use or D A events that do not involve the entire core the fission product inventory of each of the damaged fuel rods is determined by dividing the total core inventory by the number of fuel rods in the core To account for differences in power level across the cor adial peaking factors from the facility s core operating limits report COLR or teclniical speci cations should be applied in determining the inventory of the damaged rods No adjustment to the fission product inventory should be made for events postulated to occur during power operations at less than full rated power or those postulated to occur at the beginning of core life For events postulated to occur While the facility is shutdown eg a fuel handling accident radioactive decay from the time of shutdown maybe mode e 32 Release Fractions The core inventory release fractions by radionuclide groups for the gap release and early iiivessel damage phases for DB LOCAs are listed in Ta e or BWRs and Table 2 for P Rs These fractions are applied to the equilibrium core inventory described in Regulatory Positron 31 For nonLOCA events the fractions oftlie core inventory assumed to be in the gap for the various radionuclides are given in Table 3 The release fractions from Table 3 are used 39 conjunction with the fission product inventory calculated with the maximum core radial peaking factor B phase may be assumed to be 10 minutes A licensee r 39 r 33 Timing of Release Phases Table 4 tabulates the onset and duration of each sequential release phase for DBA LOCAs at PWRs and BWRs The specified onset is the time following the initiation of the accident ie time O The early iiiVessel phase immediately follows the gap release phase The activity released from h i 39 g pha should be mndeled 39 39 k 39 1 linear fashion over the duration of the phase11 For nonLOCA DBAs in which fuel damage is projected the release from the fuel gap and the fuel pellet should be assumed to occur instantaneously With the onset of the projected damage 12 instantaneously at the start 0mm release phase i e in step increases Table 4 LOCA Release Phases 5 Phase Onset Duration Onset Duration Gap Release 30 sec 0 5 hr 2 min 05 1139 Early IiiVessel 05 hr 1 3 hr 05 hr 15 In39 For facilities licensed with leakbeforebrealt methodology the onset of the gap release se an alternative time for the onset of the gap release phase based on facilityspecrfic calculations using suitable analysis codes or on 1 accepted p39cal report shown to be applicable to the speci c facrlity In the absence tppi39oved alteinatives the gap release phase onsets in Table 4 should be used 3A Radionuclide Composition Table 5 lists the elements in each radionuclide group that should be considered in design basis analyses Table 5 Radionuclide Groups i39oup Ele ments Noble Gases Xei Kr Halo gens I Br A a s Tellurium Group Te Sb Se Ba S1 Noble Metals Ru Rh Pd Mo Tc 390 Lanthanides La Zr Nd Eu Nb Pm Pr Sm Y Cm Am Cerium Ce Pu Np 35 Chemical Form Of the radioiodine released from the reactor coolant system RC5 to the containment in a postulated accident 95 percent of the iodine released s ould be assumed to be cesium iodit e CsI in releases from fuel pins in FHAs and from releases from the fuel pins through the RC3 in DBAs other than FHAs or C As However the transport of these iodine species followin release from the fuel may affect these assumed fractions The accidentspeci c appendices to this regulatory guide provide additional details Table 310 mu glnes ol Radionuclides into Conlainqxen for BWRs n R S Pressure High Zirconium Oxidauo Nudide Early illVessel EllVessel Late IIIvessel N G quot 10 0 0 l 027 037 007 Cs 02 045 003 R 011 038 001 Sr 003 024 0 o Ba 003 02 0 1 4 6 5 Ru 0007 0004 0 la 0002 001 0 Ce 0009 00 0 Table 311 Mean Values of Radionuclide Releases lulu Containment for PWRs bow RCSPressure High Zirconium Oxidation Nudide Early lnVessel ExVessel Late lnvessel NG 10 0 0 I 04 029 007 Cs 03 039 39 006 Ti 015 029 0015 Sr 003 012 0 Ba 004 01 0 Ru 0008 0004 0 121 0002 0015 0 Ce 001 002 0 o NUREG 1465 Table 312 BWR Releases lnto Containment Gap Release39quot Early lnVessel ExVessel Late lnVessel Duralion Hours 05 15 30 100 Noble Gasesquot 005 095 0 0 Halogens 005 025 030 001 Alkali Metals 005 020 035 001 Tiallun39um group 0 005 025 0005 Barium Strontium 0 002 01 0 Noble Metals 0 00025 00025 0 Cerium group 0 00005 0005 0 Lanthanides 0 00002 0005 0 Values shown are fractions of core inventory See 39Bible 30 for a listing of the elements in each group quot39 Gap release is 3 percent if longterm fuel cooling IS maintained Table 313 PWR Releases Into Conlainment39 Gap Release39 Early InVessel EXVESSEI Lale lnVessel Duration Hours 05 13 20 100 Noble Gases 005 095 0 O Halogens 005 035 025 01 Alkali Metals 005 025 035 01 Tellurium group gt 0 005 025 0005 Barium Strontium 0 39 002 01 o Noble Metals 0 00025 00025 0 Cerium group 0 00005 0005 0 Lanthanides 0 0 0 0002 0005 39 Values shown are fractions of core invento See 39lahle 38 for a listing of he elements in each group quot Gap release is 3 percent if longterm i39uel cooling is maintained Medical Sources Diagnostic Xrays include Medical and dental Xray units lt250 kVp Fluoroscopy units Computed tomography CT or CAT Mammography Diagnostic nuclear medicine includes Radiopharmaceuticals for imaging 99mTc 1231 204T1 1 Xe e g SPECT imaging PET scans Radioactive tracers thyroid uptake e g Bone densitometers 153Gd Radiation therapy includes Teletherapy sources 137Cs 60Co eg Sealed source applicators or brachytherapy sources IntracaVitary or Interstitial 1251 1921r 9OSr 226Ra 60Co 198Au eg Radioactive materials 1311 eg LINAC electron or photon beams Orthovoltage X ray units 150 to 500 kVp MegaVoltage or supervoltage Xray units 05 to 10 MW Xray Machine HV1 H H high 2 xrays Be window 39 AI filters Xrays Diagnostic XRays 0 Xray production due to radiative losses by electrons that have been accelerated to a target 0 Characteristic Xrays may also be produced by filling of electron shell vacancies o Electrons are emitted by a filament operated at the tube current 0 Potential difference between filament and target cause acceleration of the emitted electrons 0 Xray tube is evacuated to eliminate air absorption and scattering 0 Diagnostic XRays Xray energy spectrum is typically continuous and decreasing with a maximum energy in keV equal to the maximum kVp used during operation The effective energy is a fraction of the maximum energy Xray window filters eliminate low energy photons X ray tubes are shielded for leakage in other directions Xray sources are treated as point sources with a measured output HVL increases with shielding due to beam hardening higher energies survive shield Direct Molybdenum Mo Spectrum at 28 kVp Cnums mm mm Enemy mm n 2 a s n1n121t1511192121252129 Enemy 9V Diagnostic X Ray Spectra Dlrect Tungsten W Spectrum at 100 mp End Point Energy WV o s manuzaasu was 53571 75323354100105 Energykev Medical XRay Sources X ray machine is a shielded evacuated tube with an electron filament target and lter X ray production through the radiative loss process bremssthralung by electrons with the target W or Mo eg Characteristic Xrays may also be produced from collisional losses by electrons Tube Xray energies quality vary up to tube voltage kVp Emitted X ray quality depends on kVp and on filtration HVL are used to characterize beam quality 05 e39gHVL HVL ln 2 Radiation intensity uence XZ of target kVp2 and tube current L in mA eg Filters are used to eliminate useless low energy Xrays Filter material is typically Al Medical XRay Sources Radiation field depends on distance d fieldimage size or collimation NOTE Source to Skin Distance SSD is used for patient dose Source to Image Distance SID is used for image quality Tube current is focused on a small area of the target focal spot so xray machines are treated as point sources Patient dose depends on xray quality intensity patient orientation eld size and duration Standardized exposure information per mAs is given for kVp and ltration at a distance of 1 m Organ dose per unit exposure is given for different HVL mm Al Effective doseequivalent for an exam is given by HEe7JrWTHT NONMEDICAL SOURCES WEE Cabinet Xray devices Industrial radiography Xray units 60Co 137Cs 192Ir e g Industrial gauges Level amp Density gauges Welllogging e g 908r Y 137Cs60Co 239PuBe 241AmBe252Cf e g Consumer products and miscellaneous sources cigarettes natural gas old TV VDT luminescent watches dentures some types of glass some foods spring water luggage Xray smoke detectors welding rods lantern mantles air travel some building materials Mining Milling Fuel Fabrication and Fuel Reprocessing U radon and decay products from U and phosphate mining and milling operations Mill tailings contain U and can be a source of direct exposure radon release and surfacewater contamination Dust from phosphate ore processing lead to internal and external dose U depleted in 235U from fuel fabrication Minor airborne and liquid releases occur Fuel reprocessing results in atmospheric release of 85Kr 14C02 1291 vapors 3H vapor and gas Long lived nuclides in solidified materials include 14C 3HD 1E1D 9081 137CSD 134CSD lOGRu Nuclear Explosives Atmospheric and undergroundunderwater nuclear weapons Production and release of ssion products Atmospheric release resulting in deposition over wide areas Signi cant nuclides 14C 137Cs 95Zr 9OSr 106Ru 144Ce 3H Mm Radioactivity content of coal Nuclide B4qkg1 40K 5 0 238U decay series 20 232Th decay series 20 EXPOSURE TO NATURAL SOURCES OF RADIATION Cosmic extraterrestrial Radiations protons and alphas in space Within earth39s atmosphere neutronselectrons muons pions gamma rays and Xrays and cosmogenic nuclides Muons and electrons at surface of earth Varies with elevation and latitude Geomagnetic latitude variation higher at poles Van Allen belts trapped charged particles p amp e Dose increases with elevation concem in air ights Solar ares alter intensity Maxima in ares leads to minima in dose at earth39s surface due to perturbation of the earth39s magnetic eld Solar Wind composed of charged particles protons alphas and is a concern in space missions Doses may exceed occupational limits for long duration high altitude missions Nuclides produced 7Be om interactions with O N 14N nap 14C 14N 113311 12C 160 113311 14N Terrestrial 258U decay products radon 222Rn 255U decay products actinon 219Rn ZZTh decay products thoron 220Rn Radon Decay Series U and Th decay to isotopes of radon ZZZRn quotRadonquot and 220Rn quotThoronquot Rn is a noble gas inert and is mobile Rn isotopes are shortlived and decay products are even shorter lived nuclides some of which emit alpha particles Rn gas hazard is minor compared to internal dose hazard associated with decay products from indoor exposure bronchial epithelium Simpli ed decay schemes 238U 2 22 2 22212112 218130 Z 21 2 214131614130 21 232Th 2 224Ra Z 2an Z 216130 Z 21 Z 212131 212130 2 208Pb 1 203H 2 6 Due to the low natural abundance of U its decay to 396 s halflife 219Rn quotActinonquot is typically not a concern Alpha radiation is of concern with Rn exposure RADON ASSESSMENT 0 Sample and assess Rn gas using collect gas charcoal canister track etch film with filter Rn decay products using particulate filter track etch film with no filter RADON ASSESSMENT kamz Level WL x1 1 3 E78 MeY mi from Rn decay WLE 1369n 7680 39m LJEJMsV here n 15 number of F1 n 15 number 0 15 number 0 f f39 13 moms WL 1mm 3c 541mi 3c 373m CDC here c is pCIl of f Pc RaA C2 is pCIl of Pb RaB C is pCIl of quot 51 RaC thkmz Level Mend G M m Demo n here 170 is the number mfwmkmg hours m one mom Egmhbnum Facmx m g de ned for an mde decay product f 0 daughcer w 2km ratio Typicai auos 10 90 70 7 fax mdludual decay pmducts F de ned fox me enme decay senes hare 12 M equation is g en H ext Typical values cf equates to r Value ofO 712 Typical F value assumed far 1ndcor ma 0 5 Egmhbnnm Eguwalenl oncennanon 120 same mm pmenhax alpha decay euergv concemralmn as me rmxnlre winch 15 In none ethbnum EEC r 0 A ethbnum Rn decay pmdnd cancemratwn equals am ofRn gas For mRn 1 WI 00 pcm m equmbnum r 1 1 WT zoopcm m on 5 1 WT 7140 pcm m on 712 For mRn 1 WI 7 43 pcm at r mgancn Techmgues Sums remm aL prcssxble Increase ennlalmn mh oumde aur Subrslab Venulancn and pmce Vapm39 bmncr under slab Pam slab as a smgle mm Use rebut 0 reduce cmckmg Seal pcnen39anans and cracks mcludmg mp and bonom Mack concrem walls Use charcoal adsorbenhcldup svsmms for radnn m ground waxex 3115 Vennh e alea bybmmg Dumas an mm space mm negauve pressure Mm recirculated an e g fumace absnlute lms EPA Gmdelmes w Homemmers m Recnmmended Remedxal Acncn Tunerable lt 4 None 4 m 20 In a few years 20 m 200 In a few mamhs gt 00 Immedxamly New F OH 3 IS assumed by EPA 4 pCl l 0 02 WL Source Strength Activity and Source Sirengh Activity39 A f 439 abs 1 quot radiatim typeand mergy eg Bquotat0511MeV S AY whae S is source strmgh A is source decay rate Y is demy Radian or frequency or yield For extended sources assume uniform dlSlribLllan nfaeiivily emnelr39 39mbol U r Line Q m 5 Pan per Llnll distance per unit time Area an per unn area er umi ume Volume Sl Pan per lel vulumeper uml ume Specific Activity 39 kg cg 1 number ofm 3 6023 E23 moms pd mole molecular weight in g per mole A I my purunl man N M is O O 0 Point Source Flux Density Fluence Rate D S Ar ie point on surface of a sphere with radius r Assumes radiation emission is isotropic In spherical coordinates T 37 A f f 139 112 r sin HLIH u i 13139 Thus D S 4Trr2 Particle Flncnc 12 Number ol39parncles that during speci ed period penetrate the cr AN MI 17 l 39mAAvo 1 AA dA cctional arm ol a sphere Unlla y cm39j 3 cm39j 11 cm391 Flltcncc Rate or Flux Fner Flux DCnbll Ill limpg dNdA At dt dt Units 7 cm39l Unus McV cm392 Fluencc Rate urFlux Densitv 11b and Encrw Flux Dcnsitv D For all values nl39E at dlSt dnCC r gtrIdE rE IrIdE rEE Examples Calculnlc SY 1hr i mCi nl39mC s NOTE y per I nl39uTs is due 0 IT lcc nl39mmBrL which is due 10 D decay 01 quotK s sv3397E7dpsx 09313x 08 99v s 313 71 V s Calculaie SA 0139 15 CI DIWCOCII Atomic m 39Co 0 g mole and C 35 g mole 39 7 a 1 37E p5 Tl y y yields 2 pholons from beta yield ol39999S and photon from hem yic 0100012 7yly 5 daynldnyZ4hnlh3 417E9squot i l ab d 4l7E9 1 21319 til 23E233l132E1900 ES g Ji E2 Ci gquot OR SA 417079 5quot 602 E23 11 molequot l 0 g molcquot37 E10 dps Ciquot 5 2 E 2 Cl gquot 3 2 0 Example EXAMPLE 7 Calculalc 3 by and IE mm a poim source containing 1 pCi each 01quot37CsquotquotCo and Zn 1 1 a1 a dismncc 039 5 cm 1 For a point source 4 Sy 4 72 IEquot Nuclide IVICVY quotd S 1 C5 137 0662 0185 315154 108 71 CDAGU 1173 10 370154 137 14 9 C04 1 332 10 370134 127 16 7 211765 0 511 0034 18915 647 72 ZIP5 1 115 051 12 043 022 Total 12 43E1 46E1 Unm ys cm39ls 39 Mchm39lsquot 0 Photon Source Strength Energy groups are used for multiple radionuclide sources with discrete energies e g ssion products and for continuous energy distributions e g Xray machines Groups are de ned by energies that have similar attenuation or energy absorption properties Photon energies with similar mass attenuation coe icients Q or rmss energy absorption coe icients Q11 W rmy be combined into groups weighted by the source strength lt E5 EEY AY for photons With similar Q or Q1 values Where lt E is the average energy for that group and Q or Q1 values apply for a specified material Photon Interaction Coefficients Data 0 Mass attenuation and energy absorption coefficients are available in various texts and publications and at the following internet sites NIST Physical Reference Data XRav amp W NIST XRav Mass Attenuation Coefficients W httpbhvsicsnistqovthsRefDataXravMass Coefcoverhtml httpbhvsicsnistqovthsRefDataXcomht mlxcom1thtml Example 0 Mo99 Tc99m generator used in nuclear medicine Analyze production of Mo99 Characterize the source Determine photon energy groups Determine photon flux densities Point source geometry is assumed 77 5 Mn 6 4ch W 1 Nunin Mldc39dHL 39 Aw WHW W7 51439le M M 5 m 007 Akpph j 1 141 we m eha4 1min 4 2 mxA at W194 wigLag I AIM mohw39ly 5 c 7 4 l AAi vlw m an mu m Jaghmdoa l 39rwiii39 Pl 5 7 A a a Mde A quotM k l 1 a 3 1 u Xlt01RLw E 9 Mfua SW Mmunkaa39 90 a 1 5 7 p1 10Mun grinding 13923 41494 7144 4 Jan3d AlpMM 2439 frwude Lszr 1141 Maui 24439 Jnx h m M mu byA at 4 1441137 cam m Huang Wm f my a 77mg malou Lag Mun 1cm 0J3 of M zzfg V 4c a N YEe739 3 93quot 5 35 A 7 03510Pa 5 6 y 1 A 7216 14 N 7gon 13jrzsgnadm Ila97c j LgZS Hg rA 17255Aquot 139 2 L 7571 Mm 4 Wm M Ar lFl i p y I 7397 m4 PW f rInur39 r r7H met 5 9 120506 2EI 1JM 0 719 3 L L 77mr L Mum a War 4MP wHA mm 9 3 quotIr T 141 ra N Ele Z J N 7 Mra2L6mzen f7o auo j L515 7 gigLgi l395qggd139d 639 oAz l a 13996 n cm 7 rm Sh W T v waJL er mer a 5 Ru Hade 5 u ml My armLINN IA m7 471quot y l7L A N 5 Win77 F1 Km K A J s N gt A 4 39 c 7 NI 7 3 N2 7197 Huh NJ He 2 v MP AIo e M F nz z M RX 4 Ma 1 9 939 7 M m M 0753 41quot Hquot U a m A N Am quot Au gritJ Yf1d M 511 Mr 176041 ltm m3 mm mm o W M3 ms 7 57 Al 0 m 11 9 m IKE M 01 NW NW 1467 a w 9122 Val 9 1375 3977y a 11V AWN ggsgq 4 0323 0 Mil W 7 w s v quot72 1mm 9141 5 216m Mag Nagy WM 19 mp 57m F ApjFJZ A1 nltEgt ZSAFA ZS aged ltoo hl A A D I Z I V E a 397 flla llI air1156 np pa L 1 Jr W 75674 II DEII mus9 AFNHel m mmnw m f 177 Z p34 mu d 2736 rJ 2376 n 4 33 q 11 1 11 ansawn I 0762an 65 124560 VJ Consider the following batch decay chain Ali N Is Tc 99 B HI d u p a ii m man 4 v i 39 K 39 39 39 stable nuclide 7 The net me of change of each nllclide 11 the decay chain is CO n ce rn W L 71PM dr The soimious m these equations are e 71 7mg No 2 W 7241 XX VJ lit 544 g A N ii i XJ MXAS M 11quotka AI r012 33 N4 N i ee WHNZ N3 rm a marerml Ziamice 0 To 99 Activity Calculation o Tc99 is longer lived than Mo99 210000 y vs 66 h 0 Within a few weeks eg gt 28 days all Mo99 atoms that were initially present decay to Tc 99 0 Therefore D A0 1 expt A D AOfortgt10 T12 where D is total decays or total number of atoms of Mo99 o A AN 0 So Tc 99 activity ln2 210000 v8760 hvl 5 Ci37E1O dpsCi1 atom decay In 2 66h 664 E3 dps or 18 E7 Ci or 02 uCi 000000 00 Internet References httpwww nrcqov httpwwweoaqovradiation wwwnistgov httpwwwbqovabcindexhtm httpwwwbqovabcwachartquidehtml httphyperphysicsphy astrqsued uhbasehframehtm httpwwwieminccomhomesethtm httpwwwradprocalcuIatorcomndexaspx httpwwwwiseuraniumorqindexhtml Internet References 0 httpiebqov o httpiebqovtoipercharthtm o httpiebqoveducationisotopeshtm o httpwwwbqovabcwallchartquidehtml o httpwwwnndcbnqovindexisp o httpwwwnndcbnlqovmirdindexhtm o httpwwwnndcbnlqovnudat2indexisp
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