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Title: Development of the FHR advanced natural circulation analysis code and application to FHR safety analysis

The University of California, Berkeley (UCB) is performing thermal hydraulics safety analysis to develop the technical basis for design and licensing of fluoride-salt-cooled, high-temperature reactors (FHRs). FHR designs investigated by UCB use natural circulation for emergency, passive decay heat removal when normal decay heat removal systems fail. The FHR advanced natural circulation analysis (FANCY) code has been developed for assessment of passive decay heat removal capability and safety analysis of these innovative system designs. The FANCY code uses a one-dimensional, semi-implicit scheme to solve for pressure-linked mass, momentum and energy conservation equations. Graph theory is used to automatically generate a staggered mesh for complicated pipe network systems. Heat structure models have been implemented for three types of boundary conditions (Dirichlet, Neumann and Robin boundary conditions). Heat structures can be composed of several layers of different materials, and are used for simulation of heat structure temperature distribution and heat transfer rate. Control models are used to simulate sequences of events or trips of safety systems. A proportional-integral controller is also used to automatically make thermal hydraulic systems reach desired steady state conditions. A point kinetics model is used to model reactor kinetics behavior with temperature reactivity feedback. The underlying large sparsemore » linear systems in these models are efficiently solved by using direct and iterative solvers provided by the SuperLU code on high performance machines. Input interfaces are designed to increase the flexibility of simulation for complicated thermal hydraulic systems. In conclusion, this paper mainly focuses on the methodology used to develop the FANCY code, and safety analysis of the Mark 1 pebble-bed FHR under development at UCB is performed.« less
Authors:
 [1] ;  [2] ; ORCiD logo [3] ; ORCiD logo [2] ;  [2] ;  [4]
  1. Xi'an Jiaotong Univ., Xi'an (China). Dept. of Nuclear Science and Technology; North China Electric Power Univ., Beijing (China). School of Nuclear Science and Engineering; Univ. of California, Berkeley, CA (United States). Dept. of Nuclear Engineering
  2. Univ. of California, Berkeley, CA (United States). Dept. of Nuclear Engineering
  3. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
  4. Xi'an Jiaotong Univ., Xi'an (China). Dept. of Nuclear Science and Technology
Publication Date:
Grant/Contract Number:
AC02-05CH11231; 91326201
Type:
Accepted Manuscript
Journal Name:
Progress in Nuclear Energy
Additional Journal Information:
Journal Volume: 91; Journal Issue: C; Journal ID: ISSN 0149-1970
Publisher:
Elsevier
Research Org:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org:
USDOE Office of Nuclear Energy (NE); National Natural Science Foundation of China (NNSFC)
Country of Publication:
United States
Language:
English
Subject:
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS; FHR; Natural circulation; Code methodology
OSTI Identifier:
1393064
Alternate Identifier(s):
OSTI ID: 1341205