Validation of HELIOS for ATR Core Follow Analyses
- Idaho National Lab. (INL), Idaho Falls, ID (United States)
This work summarizes the validation analyses for the HELIOS code to support core design and safety assurance calculations of the Advanced Test Reactor (ATR). Past and current core safety assurance is performed by the PDQ-7 diffusion code; a state of the art reactor physics simulation tool from the nuclear industry’s earlier days. Over the past twenty years, improvements in computational speed have enabled the use of modern neutron transport methodologies to replace the role of diffusion theory for simulation of complex systems, such as the ATR. More exact methodologies have enabled a paradigm-shift away from highly tuned codes that force compliance with a bounding safety envelope, and towards codes regularly validated against routine measurements. To validate HELIOS, the 16 ATR operational cycles from late-2009 to present were modeled. The computed power distribution was compared against data collected by the ATR’s on-line power surveillance system. It was found that the ATR’s lobe-powers could be determined with ±10% accuracy. Also, the ATR’s cold startup shim configuration for each of these 16 cycles was estimated and compared against the reported critical position from the reactor log-book. HELIOS successfully predicted criticality within the tolerance set by the ATR startup procedure for 13 out of the 16 cycles. This is compared to 12 times for PDQ (without empirical adjustment). These findings, as well as other insights discussed in this report, suggest that HELIOS is highly suited for replacing PDQ for core safety assurance of the ATR. Furthermore, a modern verification and validation framework has been established that allows reactor and fuel performance data to be computed with a known degree of accuracy and stated uncertainty.
- Research Organization:
- Idaho National Lab. (INL), Idaho Falls, ID (United States)
- Sponsoring Organization:
- USDOE Office of Nuclear Energy (NE)
- DOE Contract Number:
- AC07-05ID14517
- OSTI ID:
- 1177209
- Report Number(s):
- INL/CON-13-30718; TRN: US1500145
- Resource Relation:
- Conference: PHYSOR 2014. The role of reactor physics toward a sustainable future, Kyoto (Japan), 28 Sep - 3 Oct 2014
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ATR REACTOR
REACTOR CORES
H CODES
VALIDATION
COMPARATIVE EVALUATIONS
REACTOR SAFETY
NEUTRON TRANSPORT THEORY
ACCURACY
COMPUTERIZED SIMULATION
POWER DISTRIBUTION
CONFIGURATION
CRITICALITY
DESIGN
NUCLEAR FUELS
PERFORMANCE
TOLERANCE
VERIFICATION
Advanced Test Reactor
As-Run
Core Follow
Critical Eigenvalue
Fuel Inventory
HELIOS
Startup Prediction