Deterministic Modeling of the High Temperature Test Reactor with DRAGON-HEXPEDITE

Conference · Mon Oct 18 00:00:00 EDT 2010

OSTI ID:989871

Ortensi, Javier ^[1]; Cogliati, Joshua J. ^[1]; Pope, Michael A. ^[1]; Bess, John D. ^[1]; Ferrer, Rodolfo M. ^[1]; Bingham, Avery ^[1]; Ougouag, Abderrafi M. ^[1]

---

1. Idaho National Laboratory (INL), Idaho Falls, ID (United States)

The Idaho National Laboratory (INL) is tasked with the development of reactor physics analysis capability of the Next Generation Nuclear Power (NGNP) project. In order to examine the INL’s current prismatic reactor analysis tools, the project is conducting a benchmark exercise based on modeling the High Temperature Test Reactor (HTTR). This exercise entails the development of a model for the initial criticality, a 19 fuel column thin annular core, and the fully loaded core critical condition with 30 fuel columns. Special emphasis is devoted to physical phenomena and artifacts in HTTR that are similar to phenomena and artifacts in the NGNP base design. The DRAGON code is used in this study since it offers significant ease and versatility in modeling prismatic designs. DRAGON can generate transport solutions via Collision Probability (CP), Method of Characteristics (MOC) and Discrete Ordinates (Sn). A fine group cross-section library based on the SHEM 281 energy structure is used in the DRAGON calculations. The results from this study show reasonable agreement in the calculation of the core multiplication factor with the MC methods, but a consistent bias of 2-3% with the experimental values is obtained. This systematic error has also been observed in other HTTR benchmark efforts and is well documented in the literature. The ENDF/B VII graphite and U₂₃₅ cross sections appear to be the main source of the error. The isothermal temperature coefficients calculated with the fully loaded core configuration agree well with other benchmark participants but are 40% higher than the experimental values. This discrepancy with the measurement partially stems from the fact that during the experiments the control rods were adjusted to maintain criticality, whereas in the model, the rod positions were fixed. In addition, this work includes a brief study of a cross section generation approach that seeks to decouple the domain in order to account for neighbor effects. This spectral interpenetration is a dominant effect in annular HTR physics. This analysis methodology should be further explored in order to reduce the error that is systematically propagated in the traditional generation of cross sections.

• Research Organization: Idaho National Lab. (INL), Idaho Falls, ID (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA), Nuclear Criticality Safety Program (NCSP); USDOE Office of Nuclear Energy (NE)
• DOE Contract Number: AC07-05ID14517
• OSTI ID: 989871
• Report Number(s): INL/CON-10-18012; TRN: US1007172
• Resource Relation: Conference: 5. International Conference on High Temperature Reactor Technology (HTR 2010) , Prague (Czech Republic), 18-20 Oct 2010; Related Information: https://www.ans.org/meetings/view-113/
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
97 MATHEMATICS AND COMPUTING
BENCHMARKS
CONFIGURATION
CONTROL ELEMENTS
CRITICALITY
CROSS SECTIONS
DESIGN
DISCRETE ORDINATE METHOD
GRAPHITE
HTTR REACTOR
MULTIPLICATION FACTORS
NUCLEAR POWER
PHYSICS
PROBABILITY
REACTOR PHYSICS
REACTOR TECHNOLOGY
SIMULATION
TEMPERATURE COEFFICIENT
TRANSPORT
Nuclear Criticality Safety Program (NCSP)
Benchmark
Criticality
DRAGON
HEXPEDITE
HTTR
NGNP
Prismatic