Shutdown Dose Rate Analysis Using the Multi-Step CADIS Method

Journal Article · Thu Jan 01 00:00:00 EST 2015 · Fusion Science and Technology

DOI:https://doi.org/10.13182/FST15-123· OSTI ID:1214480

Ibrahim, Ahmad M. ^[1]; Peplow, Douglas E. ^[1]; Peterson, Joshua L. ^[1]; Grove, Robert E. ^[1]

---

1. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

The Multi-Step Consistent Adjoint Driven Importance Sampling (MS-CADIS) hybrid Monte Carlo (MC)/deterministic radiation transport method was proposed to speed up the shutdown dose rate (SDDR) neutron MC calculation using an importance function that represents the neutron importance to the final SDDR. This work applied the MS-CADIS method to the ITER SDDR benchmark problem. The MS-CADIS method was also used to calculate the SDDR uncertainty resulting from uncertainties in the MC neutron calculation and to determine the degree of undersampling in SDDR calculations because of the limited ability of the MC method to tally detailed spatial and energy distributions. The analysis that used the ITER benchmark problem compared the efficiency of the MS-CADIS method to the traditional approach of using global MC variance reduction techniques for speeding up SDDR neutron MC calculation. Compared to the standard Forward-Weighted-CADIS (FW-CADIS) method, the MS-CADIS method increased the efficiency of the SDDR neutron MC calculation by 69%. The MS-CADIS method also increased the fraction of nonzero scoring mesh tally elements in the space-energy regions of high importance to the final SDDR.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE
• Grant/Contract Number: AC05-00OR22725
• OSTI ID: 1214480
• Journal Information: Fusion Science and Technology, Vol. 68, Issue 3; ISSN 1536-1055
• Publisher: American Nuclear Society
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY