Mr. John Link
Principal Consultant
Zachry Nuclear Engineering, Inc.

Mr. Rodney Harvill
Senior Consultant
Zachry Nuclear Engineering, Inc.

Abstract

A GOTHIC model of the liquid sodium Experimental Breeder Reactor – II (EBR-II) has been developed using only publicly available information and simulations have been run to benchmark the model to data from the Shutdown Heat Removal Tests (SHRT) #17 and #45R, which correspond to protected and unprotected loss of flow events. It was demonstrated that GOTHIC includes both the required attributes to model the EBR-II and the appropriate physics to accurately simulate the steady-state operating conditions as well as the SHRT-17 and SHRT-45R tests. The GOTHIC model of the EBR-II reactor was developed using only publicly available information. The GOTHIC results show good agreement in both magnitude and trend with the experimental data.

GOTHIC is used to benchmark steady-state and transient conditions in the Molten Salt Reactor Experiment (MSRE) with a model developed using only publicly available information.  In this experimental reactor, UF4 fuel was dissolved in molten fluoride salt, and criticality could be achieved only in the graphite moderated core.  An air-cooled radiator transferred fission and decay heat to the environment. GOTHIC is used to benchmark system operating parameters at both the 10 MWt design condition and the 8 MWt operating condition, both with and without decay heat.  Decay heat is applied using radioactive tracers to simulate eleven decay heat precursors.  The results of the benchmark exhibit good agreement with design and operating data and demonstrate heat-up due to decay heat in the fuel salt outside the core.

In the MSRE, delayed neutron precursors are not confined to the core because the fuel and fission products flow through the system.  As a result, there are different values for (effective) delayed neutron fraction with and without flow, and the decay of delayed neutron precursors outside the core under full-flow conditions reduces reactivity by 0.212 % δk/k.  The GOTHIC of the MSRE has been used to benchmark zero power physics testing transients following fuel salt pump start-up and coast-down with automatic control rod movement to maintain criticality.  The control rod motion calculated by GOTHIC is a reasonable match to measured data from these transients. Also evaluated is a low power testing natural convection transient with no control rod motion such that reactor power responds to heat load demand from the radiator.  The reactor power and fuel salt and coolant salt temperatures calculated by GOTHIC exhibit good agreement with measured data.

Biography: John Link

As a Principal Consultant with almost 40 years of nuclear power experience, Mr. Link has a broad range of experience in engineering, training and operations disciplines. His recent work has focused on advanced reactor applications of GOTHIC, including sodium cooled designs such as EBR-II and TerraPower’s TWR as well as molten salt reactors such as the MSRE. He is also the lead GOTHIC trainer, developing and delivering several training classes per year. Prior to joining Zachry, Mr. Link worked as a Shift Technical Advisor and safety analyst at TMI-I, as a containment and safety analyst for AREVA NP and was a U.S. Navy Nuclear Engineering Officer, serving on two nuclear powered cruisers. He also has experience in model development, analyses and review in various thermal hydraulics codes, such as RELAP5, RETRAN, GOTHIC, CONTEMPT, and MAAP.

Biography: Rodney Harvill

A Senior Consultant with 25 years of nuclear power experience, Mr. Harvill has a broad range of experience in operations and engineering.  He primarily functions as a lead engineer for thermal-hydraulic engineering analyses for nuclear industry clients.  Prior to joining Zachry, Mr. Harvill was a safety analysis engineer at the Palisades nuclear plant and an enlisted nuclear power plant operator in the U.S. Navy, serving on a nuclear powered aircraft carrier during its involvement in the First Gulf War.  As an undergraduate and graduate nuclear engineering student, Mr. Harvill supported research for both the Advanced Neutron Source and the Spallation Neutron Source.  He also has experience in model development, analyses and review in various thermal hydraulics codes, such as RELAP5, GOTHIC, CONTEMPT, and PIPE-Flo.

***This seminar will be streamed live on our NCStateNuclear YouTube channel***