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Title: RELAP-7 Pressurizer Component Development Updates

RELAP-7 is a nuclear systems safety analysis code being developed at the Idaho National Laboratory (INL). RELAP-7 development began in 2011 to support the Risk Informed Safety Margins Characterization (RISMC) Pathway of the Light Water Reactor Sustainability (LWRS) program. The overall design goal of RELAP-7 is to take advantage of the previous thirty years of advancements in computer architecture, software design, numerical methods, and physical models in order to provide capabilities needed for the RISMC methodology and to support nuclear power safety analysis. The code is being developed based on Idaho National Laboratory’s modern scientific software development framework – MOOSE (the Multi-Physics Object-Oriented Simulation Environment). The initial development goal of the RELAP-7 approach focused primarily on the development of an implicit algorithm capable of strong (nonlinear) coupling of the dependent hydrodynamic variables contained in the 1-D/2-D flow models with the various 0-D system reactor components that compose various boiling water reactor (BWR) and pressurized water reactor nuclear power plants (NPPs). As part of the efforts to expand the capability for PWR simulation, an equilibrium single-region pressurizer model has been implemented in RELAP-7. The pressurizer component can simulate pressure and water level change through insurge, spray, and heating processes. Two simplemore » tests – one for insurge process and another for outsurge process – have been reported to demonstrate and verify the functions of the pressurizer model. The typical single-phase PWR system model presented in the first RELAP-7 milestone report has been updated, as part of system level test for the new pressurizer model. The updated PWR system model with the pressurizer component can be used for more realistic transient simulations. The addition of the equilibrium single-region pressurizer model represents the first step of developing a suite of pressurizer models with different levels of fidelities. Non-equilibrium two-region two-zone model and non-equilibrium five-region three zone model will be implemented in the near future. Cross comparison and validation will be pursued when higher fidelity pressurizer models are completed.« less
Authors:
 [1] ;  [1] ;  [1] ;  [1] ;  [2] ;  [2]
  1. Idaho National Lab. (INL), Idaho Falls, ID (United States)
  2. Oregon State Univ., Corvallis, OR (United States). Dept. of Nuclear Engineering and Radiation Health Physics
Publication Date:
OSTI Identifier:
1262489
Report Number(s):
INL/EXT--16-38185
TRN: US1601604
DOE Contract Number:
AC07-05ID14517
Resource Type:
Technical Report
Research Org:
Idaho National Lab. (INL), Idaho Falls, ID (United States)
Sponsoring Org:
USDOE Office of Nuclear Energy (NE)
Contributing Orgs:
Oregon State Univ., Corvallis, OR (United States)
Country of Publication:
United States
Language:
English
Subject:
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS; 97 MATHEMATICS AND COMPUTING; PWR TYPE REACTORS; NUCLEAR POWER PLANTS; BWR TYPE REACTORS; EQUILIBRIUM; COMPUTERIZED SIMULATION; R CODES; SAFETY ANALYSIS; VALIDATION; NONLINEAR PROBLEMS; REACTOR COMPONENTS; HEATING; SPRAYS; TRANSIENTS Pressurizer; PWR; RELAP-7