Recent Activities of MA Cross-Section Measurements

Transcription

1 2006Symposium on Nuclear Data 25 January, 2007 Recent Activities of MA Cross-Section Measurements JAEA Kyoto Univ. S. Nakamura, M. OHTA, and H. Harada T. Fujii and H. Yamana 2006 Symposium on Nuclear Data SND2006-V.01-1

2 High Level Waste (HLW) Fission Products(FP) 99 Tc, 129 I, 137 Cs, 90 Sr, Minor Actinides(MA) Sr, I. 237 Np, 241, 243, 244. Public Acceptability of Nuclear Power Reactors Waste Management Environment Cross Section Measur. Nuclear Transmutation Activation Method Time-Of Of-Flight Prompt -rays.. etc Symposium on Nuclear Data SND2006-V.01-2

3 237 U Chart of the nuclides 238 U 239 U Basic Reaction for FBR 238 Np 237 Np 239 Np The build-up of these nuclides is important for waste management, for decay-heat studies, and for the fuel cycle. 238 Pu 239 Pu 240 Pu 241 Pu 242 Pu 242m g 243 Decay-heat Higher isotopes 2006 Symposium on Nuclear Data SND2006-V.01-3

4 m,g Motivation , 246, 7370yr 18yr 8500yr 4730yr Long-half life 7370yr. Production of long-lived isotopes Discrepancies among the cross section data ~about 10% m (b) g (b) m+g (b) JENDL-3.3 ー ー 76.7 Mughabghab 71.3± ± ±1.8 Letourneau ー 5.2± ±3.9 Schuman ー 5.9 ー Ice Street 50 ーー 2006 Symposium on Nuclear Data SND2006-V.01-4

5 Partial Decay Scheme of 243 I m =1820±70 (b) m =75.1±1.8 (b) m 7370 yr (87.4%) (11.0%) 244 Pu g =3.8±0.4 (b) I g =94±9 (b) E.C. ~26min 244g 10.1 h % yr (76.4%) (23.6%) 2006 Symposium on Nuclear Data SND2006-V.01-5

6 243 Sample for 243 1Ci High purity quartz tube 7mmφ 25mm Au/Al wire Co/Al wire 0.5mm 1.mm 10H Irrad. ネジ式のアルミ容器 Irradiation capsule for Hyd Symposium on Nuclear Data SND2006-V.01-6

7 -ray spectrum of irradiated 243 sample 8000 Counts MeV ~1 month cooling 30 min measur MeV Channel 2006 Symposium on Nuclear Data SND2006-V.01-7

8 Analysis of effective cross-section T irr th m g 243 Y m g 244m ~26min g 10.1 h - Y Reaction Rate: R Y Y 1 T irr Effective Cross Section: eff R th 2006 Symposium on Nuclear Data SND2006-V.01-8

9 Results of effective cross section for the 243 (n,) 244m+g reaction ˆ mg This Work* JENDL-3.3 (2002) Mughabghab (1984) 174.0± ±7 *M.Ohta et al.: J.Nucl.Sci.Technol.,43, 1441, (2006) Symposium on Nuclear Data SND2006-V.01-9

10 Motivation m,g Pu Related to production of 239 Pu Production of long-lived isotopes Problem of decay heat 242 (163 day) Discrepancies among the reported data: 0 ~more than 20% Refernces Year Maidana et al. (2001) Fioni et al. (2001) Shinohara et al. (1997) Gavrulov et al. (1977) Harbour et al. (1973) Bak et al. (1967) Deal et al. (1964) 768±58 780±50 748±20 670± (b) 602±9 636± ± ± ± I 0 (b) Symposium on Nuclear Data SND2006-V.01-10

11 JENDL k b at eV ev ev This Work Cut-off Energy 0.1 ev Cut-off Energy 0.5 ev 2006 Symposium on Nuclear Data SND2006-V.01-11

12 Partial Decay Scheme of MeV MeV yr m 238 Np g 242m 141 yr IT % yr 242g EC=17.3% h 242 Pu - =82.7% 238 Pu d MeV MeV 2006 Symposium on Nuclear Data SND2006-V.01-12

13 241 Samples for Bq 2.5l solution Co/Al 1 mm Au/Al 0.5 mm Bq 12.5l solution Co/Al 1 mm Au/Al 0.5 mm High purity quartz tube 8mmf, 50mm in length KUR@Long-Irrad. Plug 1week (68H) Irrad. 20mm in length Two folds of Al enclosure rods Gadolinium capsule 10mmf, 30mm in length 25m in thickness 2006 Symposium on Nuclear Data SND2006-V.01-13

14 Measurement of sample 20 Days Cooling after Irrad. flux monitors Irradiated 241 sample ray measurement with a Ge detector flux information 3M HNO 3 Add 50l solution ray measurement EG&G ORTEC SOLOIST 2006 Symposium on Nuclear Data SND2006-V.01-14

15 -ray spectrum of irradiated 241 sample a) bare MeV MeV b) with Gd Symposium on Nuclear Data SND2006-V Channel

16 R 0 R 0 G 1 G 1 Modifying the Westcott s convention s th 2 0 s th 2 0 I 0 0 G G epi for irradiation without a Cd shield, s 0 4 epi for irradiation with a Cd shield. where I 0 is the resonance integral after subtracting the 1/ component R/ 0 ( n/cm 2 sec) bare 60 Co 198 Au with Gd Resonance Integral I 0 I 0 =I for cut-off energy of 0.1 ev parameter s Symposium on Nuclear Data SND2006-V.01-16

17 This Work JENDL-3.3 (2002) Maidana et al. (2001) Fioni et al. (2001) Results of 0 and I 0 for the 241 (n,) 242g reaction 0 (b) Tentative! 628± ±9 636±46 3.5±0.3 k 1456 I 0 (b) 1665± Cut-off E 0.1eV 0.5eV Shinohara et al(1997) 768± ± eV Gavrulov et al. (1977) 780± Harbour et al. (1973) 748± ± eV Bak et al. (1967) 670± Deal et al. (1964) Symposium on Nuclear Data SND2006-V.01-17

18 Summary 241 (n,) 242g Reaction: 0g = 628±22(b), I 0g = 3.5±0.3(kb) Ec=0.107eV 243 (n,) 244m+g Reaction: eff = 174.0±5.3(b) in Hyd.@KUR Evaluated data for 243 is 13% smaller than the present result Symposium on Nuclear Data SND2006-V.01-18

19 JAEA s Data for MA Cross-Sections Nuclide Half-life Past Data (Author, Year) JAEA Data References 237 Np y 0 =158±3b I 0 =652±24b (Kobayashi 1994) 0 =141.7±5.4b I 0 = 862±51b (2003) 0 =169±6b (2006) Katoh et al., JNST, 40(2003) Harada et al., JNST,43,No11(2006) 238 Np 2.1 d No Data! eff =479±24b (2004) Harada et al., JNST, 41(2004) y 0g = 768±58b I 0g =1694±146b (Shinohara 1997) 0g =628±22b I 0g =3.5±0.3kb Nakamura et al., JNST, to be submitted y 0m =80b, 0g =4.3 0m+g =84.3b (Ice 1966) eff =174.0±5.3b (2006) Ohta et al., JNST,43,No.12(2006) 2006 Symposium on Nuclear Data SND2006-V.01-19