Coordinated evaluation of 239Pu in the resonance region

Transcription

1 Coordinated evaluation of 239Pu in the resonance region Contribution of the Nuclear Data roup of Cadarache WPEC/S 34, NEA, may 202 illes Noguere SPRC/LEPh, CEA Cadarache, F-308Saint Paul Les Durance

2 Outlines Resonance-Parameters Covariance Matri (RPCM) CONRAD Marginalization Investigation of the Unresolved Resonance Range Use the URR option of TALYS Investigation of the two-step (n,f) process See Eric Fort NSE 99, 375 (988) Benchmarking ICSBEP, Mo fuel, Post Irradiated Eperiments, 2

3 3 M Resonance-Parameter Covariance Matri provided by the fitting model M Covariance matri between the nuissance parameters The covariance matri can be partionioned as follow : Resonance-Parameters Covariance Matri (RPCM) T T T T M M M T T 2 ) ( 22 = M n k k n y y y y m k k m y y y y With :

4 Resonance-Parameters Covariance Matri (RPCM) 4

5 Resonance-Parameters Covariance Matri (RPCM) Underestimated! 5

6 Investigation of the Unresolved Resonance Range TALYS calculations head-band states based on the work of Olivier Bouland (LANL/CEA collaboration) Inner barrier (n+pu-239) outer barrier (n+pu-239) Recent advances in modeling fission cross sections over intermediate structures O. Bouland, E. Lynn and P.talou, LA-UR Analysis of the (n,f) reaction in the plutonium isotopes O. Bouland, E. Lynn and P.talou, Third International Workshop on Compound-Nuclear Reactions and Related Topics (CNR*) 6

7 Investigation of the Unresolved Resonance Range How to describe the fluctuations observed in the fission cross section? Increase the upper energy limit of the RRR to 4 kev 7

8 Investigation of the Unresolved Resonance Range Impact probability tables PT(Pu-239) The interpretation of the URR parameters by CALENDF and NJOY gives differents Probability Tables. For Pu-239, CALENDF uses a group-wize representation in agreement with the work of Herve Derrien. NJOY uses a point-wize representation. (See WPEC/S32) keff results obtained with TRIPOLI4+CALENDF and MCNP5+NJOY Code system TRIPOLI4+CALENDF MCNP5+NJOY with PT( 239 Pu).5688 (± 4 pcm).5426 (± 4 pcm) without PT( 239 Pu).549 (±4 pcm).559 (± 4 pcm) impact PT( 239 Pu) - 50 pcm + 70 pcm discrepancies due to the processing codes : ma 220 pcm this problem can be solved by using LSSF= 8

9 Investigation of the two-step (n,f) process 959 : unpublished estimation of the f width for the (n,f) reaction by E. Lynn 965 : On the slow neutron, gamma-fission reaction, E. Lynn, Phys. Lett : Evaluation des données neutroniques pour le Pu-239,. LeCoq, PhD thesis 973 : Etudes des sections efficaces de réaction des neutrons de resoanance avec Pu239, H. Derrien, PhD thesis 974 : Etude des neutrons et des rayons gamma émis lors de la fission induite dans 235U et 239Pu par neutrons lents: mise en évidence de la réaction (n,gamma f), D. Shackleton, PhD thesis 980 : The double-humped fission barrier, S. Bjornholm and E. Lynn, Rev. Mod. Phys : Evaluation of p for Pu-239, E. Fort et al. Nucl. Sci. Eng. 99 9

10 Investigation of the two-step (n,f) process Neutron multiplicity evaluation p takes into account. 2 openened fission channels for J =0 + f (0) and f2 (0) f (0 + ). openened fission channels for J = + f ( + ). J-dependent width for the (n,f) reaction f (0 + ) and f ( + ) Phenomenological description ( E) p 4 i P ( E) i i Where Pi ( E) f ( E) fi ( E) f ( E) 0

11 Investigation of the two-step (n,f) process For J = +, the smallest resonances are due to the (n,f) process Problem!!!. in the evaluated file they are considered as simple (n,f) reaction. possible overestimation of the radiative capture Cf. production of Pu-240

12 Investigation of the two-step (n,f) process Significant contribution of the (n,f) process can be observed for resonances with J = + 2

13 Investigation of the two-step (n,f) process 3

14 Investigation of the two-step (n,f) process Constant terms i obtained with CONRAD from the least-squares fit to the Frehaut data. Preliminary results are compared with the results of E. Fort. Reaction J This work (Prelim.) O. Serot and E. Fort (Prelim.) E. Fort (988) (n,f) (n,f) (n,f) (n,f)

15 Benchmarking PST00.4 PST004. EALF = ev EALF = ev 5 % Pu % Pu-240 MH.2 (EOLE, Cadarache) PWR-MO miwed core 4 years BASALA-Hot (EOLE, Cadarache) BWR-MO BWR-MO 2 years 3 years MISTRAL-2 (EOLE, Cadarache) PWR-MO 8 years MISTRAL-3 (EOLE, Cadarache) PWR-MO 9 years MISTRAL-4 (EOLE, Cadarache) FUBILA-Hot (EOLE, Cadarache) ERASME (EOLE, Cadarache) MO-REF MO-AIC MO-Hf MO-B4C BWR-REF (EPICURE) BWR-NORM (EPICURE) BWR-70% Void (EPICURE) BWR-00 (EPICURE) BWR-UD (EPICURE) ERASME/R, HCPWR ERASME/S 0 years 0 years 0 years 0 years years (6-7 years) years (6-7 years) years (6-7 years) years (6-7 years) years (6-7 years) OSMOSE (MINERVE, Cadarache) Oscillation measurements (RU02 and RMOX lattices ) Post Irradiated Eperiments (PIE) RAVELINE (ALIX-HTC), UNDREMMINEN, DAMPIERRE, 5

16 Benchmarking With new Pu-239 ORNL/CEA collaboration (V.7a) ENDF\B-VII JEFF-3.. CEA2005V4 Codes MCNP T4 AP2 (Chabint) AP2 (ALILEE) PST00.4 PST004. ± 500 ± (9) (5).0027 (5) (3) MH.2 (PWR-MO mied core) BASALA-Hot (BWR-MO) BASALA-Cold (BWR-MO) MISTRAL-2 (PWR-MO) MISTRAL-3 (PWR-MO) keff at 20 C MISTRAL-4 (MO-REF) MISTRAL-4 (MO-AIC) MISTRAL-4 (MO-Hf) MISTRAL-4 (MO-B4C) FUBILA-Hot (BWR-REF) FUBILA-Hot (BWR-NORM) FUBILA-Hot (BWR-70% VOID) 270 (50) 65 (50) 692 (50) 35 (50) ~50 pcm ~32 pcm ~ 3 pcm ~ 70 pcm With new Am-24 IRMM/CEA FUBILA-Hot (BWR-00) FUBILA-Hot (BWR-UD) MISTRAL-3 (PWR-MO) RTC 0-80 C ± ± 0.3 OSMOSE (RU02 Lattice) OSMOSE (RMOX Lattice) ± 2.8 ± Pu240, Pu24 6