ENTRY 30958 20010508 00003095800000001 SUBENT 30958001 20010508 00003095800100001 BIB 10 33 3095800100002 INSTITUTE (3INDSAH) 3095800100003 REFERENCE (J,JIN,35,1793,1973) 3095800100004 AUTHOR (B.C.Purkayastha,D.K.Bhattacharyya) 3095800100005 TITLE The radiochemical yield in the spontaneous fission of 3095800100006 238U 3095800100007 SAMPLE natural uranium as reactor-grade U3O8, dissolved in 3095800100008 nitric acid (2N HNO3) 3095800100009 METHOD (ABSFY).The number of fissions were determined using 3095800100010 the uranium weight and the U-238 spontaneous fission 3095800100011 half life. For calculating the yields, the 8.04E+15 3095800100012 year half life by E.Segre, Phys.Rev.86(1959)21 was 3095800100013 used, as the yields agreed better with other published3095800100014 values. 3095800100015 COMMENT: The fission yields calculated using the 3095800100016 1.01E+16 yrs half life by R.L.Fleischer and P.B.Price,3095800100017 Phys.Rev.133(1964)B63 are also given in Table 1 of 3095800100018 J.Inorg.Nucl.Chem.35(1973)1793 but were found to be 3095800100019 discrepant with other data and therefore discarded by 3095800100020 the authors. 3095800100021 (RCHEM). as described in subentries 2 and 3 3095800100022 (BSPEC) direct beta counting 3095800100023 DETECTOR Philips low-level beta-counting assembly type PW 4127 3095800100024 ERR-ANALYS The yields given are the averages of 2 measurements but3095800100025 the nature of the uncertainty is not given. 3095800100026 STATUS Bib-information and data from J.Inorg.Nucl.Chem.35 3095800100027 (1973)1793 3095800100028 HISTORY (19881017T) automatic conversion from Rider file, ref. 3095800100029 73PUR1, to EXFOR90573 3095800100030 (19911122A) ML:converted to regular EXFOR, not checked.3095800100031 (20010508A) ML:revised entry from original reference: 3095800100032 deleted monitor Mo99 (which was given by Rider but 3095800100033 actually not used as monitor), added exprimental 3095800100034 details to BIB section. 3095800100035 ENDBIB 33 0 3095800100036 NOCOMMON 0 0 3095800100037 ENDSUBENT 36 0 3095800199999 SUBENT 30958002 20010508 00003095800200001 BIB 7 18 3095800200002 REACTION (92-U-238(0,F)42-MO-99,CUM,FY) 3095800200003 SAMPLE 6 l solution containing 3.067 kg of uranium was used. 3095800200004 Mo carrier was added and all molybdenum in the sample 3095800200005 removed chemically. 3095800200006 METHOD (RCHEM).The solution stood for 21 days to accumulate 3095800200007 fission product molybdenum. Then again Mo carrier was 3095800200008 added and Mo precipitated and purified. 3095800200009 ANALYSIS (DECAY) The decay curve for the molybdenum activity was3095800200010 measured for 15 days and found to follow the 67 hr half3095800200011 life of Mo-99. 3095800200012 CORRECTION A standardised Mo-99 source was used to determine the 3095800200013 counter geometry and required corrections for back- 3095800200014 scattering and the finite shape of the measured source.3095800200015 COMMENT The MO-99 yield given in the DATA table is based on the3095800200016 U-238 spontaneous fission half life of 8.04E+15 years. 3095800200017 The 1.01E+16 years half life would have given a fission3095800200018 yield for Mo-99 of 7.2+-0.4. 3095800200019 DECAY-DATA (42-MO-99,67.HR,B-) 3095800200020 ENDBIB 18 0 3095800200021 NOCOMMON 0 0 3095800200022 DATA 2 1 3095800200023 DATA DATA-ERR 3095800200024 PC/FIS PC/FIS 3095800200025 5.7 0.3 3095800200026 ENDDATA 3 0 3095800200027 ENDSUBENT 26 0 3095800299999 SUBENT 30958003 20010508 00003095800300001 BIB 7 32 3095800300002 REACTION (92-U-238(0,F)ELEM/MASS,CUM,FY) 3095800300003 SAMPLE 4 l solution containing 4.015 kg of uranium was used. 3095800300004 Chemical procedures were applied and the solution 3095800300005 distilled to remove all iodine already present in the 3095800300006 sample. 3095800300007 METHOD (RCHEM).The solution stood for 8 days to accumulate 3095800300008 fission product iodine. The procedure for purification 3095800300009 from iodine (see SAMPLE above) was repeated. The 3095800300010 extracted solution stood for 2 more days to allow the 3095800300011 short lived iodine isotopes to decay. Then the iodine 3095800300012 was further purified, precipitate as AgI and prepared 3095800300013 for beta counting. 3095800300014 ANALYSIS (DECAY) The decay curve was decomposed into a 20.8 hr 3095800300015 component (I-133) and an 8 day component (I-131). 3095800300016 CORRECTION The counter was calibrated using K2SO4 (as beta 3095800300017 energies of natural potassium are similar to those of 3095800300018 I-133). For self-absorption and backscattering 3095800300019 corrections, a source containing I-133 was produced. 3095800300020 COMMENT The authors state that their I-131 yield is lower than 3095800300021 that reported by other authors. The reason could be 3095800300022 that their experiment was designed to measure the I-1333095800300023 yield and they did not allow sufficient time to produce3095800300024 enough I-131. The discrepancy was probably due to 3095800300025 low counts and poor statistics. 3095800300026 The iodine yields given in the DATA table are based on 3095800300027 the U-238 spontaneous fission half life of 8.04E+15 3095800300028 years. The 1.01E+16 years half life would have given th3095800300029 following fission yields: 3095800300030 I-131 0.35+-0.20 3095800300031 I-133 7.0+-0.5 3095800300032 DECAY-DATA (53-I-131,8.D,B-) 3095800300033 (53-I-133,20.8HR,B-) 3095800300034 ENDBIB 32 0 3095800300035 NOCOMMON 0 0 3095800300036 DATA 4 2 3095800300037 ELEMENT MASS DATA DATA-ERR 3095800300038 NO-DIM NO-DIM PC/FIS PC/FIS 3095800300039 53. 131. 0.28 0.2 3095800300040 53. 133. 5.6 0.4 3095800300041 ENDDATA 4 0 3095800300042 ENDSUBENT 41 0 3095800399999 ENDENTRY 3 0 3095899999999