Modeling of the Reactor Core Isolation Cooling Response to Beyond Design Basis Operations - Interim Report

Ross, Kyle; Cardoni, Jeffrey N; Wilson, Chisom Shawn; Morrow, Charles W.; Osborn, Douglas; Gauntt, Randall O.

doi:10.2172/1229703

Cited by 10 publications

(34 citation statements)

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“…The computer aided drafting and CFD accomplishments described in Reference [6] have critically informed the latest system-level model solution (i.e., the homologous-curve solution) with respect to:…”

Section: Melcor Modeling Effortsmentioning

confidence: 99%

“…As part of the efforts to understand the unexpected "self-regulating" mode of the RCIC systems in the Fukushima Daiichi Unit 2 accidents and extend BWR RCIC and PWR AFW operational range and flexibility, mechanistic models for the Terry turbine, based on Sandia's 2015 efforts [6], have been developed and implemented in the RELAP-7 code to simulate the RCIC system. RELAP-7 is a new reactor system safety analysis code currently under development at Idaho National Laboratory [7][8].…”

Section: Relap-7 Modeling Effortsmentioning

confidence: 99%

“…INL modified the SNL Terry turbine model [6] and implemented those models into the RELAP-7 code [13]. This effort has been focused on normal working conditions.…”

Section: Relap-7 Modeling Effortsmentioning

confidence: 99%

“…Table 3 shows the major parameters for the turbine and pump. These values are taken from the SNL MELCOR case [6], which is based on a RCIC system for a generic 2,000 MWth BWR. Note that the rated pump head is not an input parameter.…”

Section: Relap-7 Modeling Effortsmentioning

confidence: 99%

“…The newly developed nozzle models and modified turbine rotor model according to the SNL work [6] have been implemented into RELAP-7 [13], along with the SNL Terry turbine model. A new RELAP-7 pump model has also been developed and implemented to couple with the Terry turbine model.…”

Section: Relap-7 Modeling Effortsmentioning

confidence: 99%

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Terry Turbopump Expanded Operating Band

Osborn

Ross

Cardoni

et al. 2017

ASME/NRC 2017 13th Pump and Valve Symposium

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The Terry turbine is a small, single-stage, compound-velocity impulse turbine originally designed and manufactured by the Terry Steam Turbine Company purchased by Ingersoll-Rand in 1974. Terry turbines are currently manufactured and marketed by Dresser-Rand. Terry turbines were principally designed for waste-steam applications. Terry turbopumps are ubiquitous to the US nuclear fleet as a steam driven turbopump in either the reactor core isolation cooling system (RCIC) and high pressure coolant injection systems for boiling water reactors (BWRs) or in the auxiliary feedwater system (AFW) system for pressurized water reactors (PWRs).Prior to the accidents at Fukushima Daiichi, assumptions and modeling of the performance of Terry turbopumps were based mostly on generic vendor use of NEMA SM23 Steam Turbine for Mechanical Drive Service guidance [1]. However, the RCIC/AFW system performance (i.e., the Terry turbopump) under beyond design basis event (BDBE) conditions is poorly known and largely based on conservative assumptions used in probabilistic risk assessment (PRA) applications. For example, common PRA practice holds that battery power (DC) is required for RCIC operation to control the vessel water level, and that loss of DC power results in RCIC flooding of the steam lines and an assumed subsequent failure of the RCIC turbopump system. This assumption for PRA implies that RCIC operation should terminate on battery depletion which can range from 4 to 12 hours. In contrast, real-world observation from Fukushima Daiichi Unit 2 shows that RCIC function was not terminated by uncontrolled steam line flooding or loss of control power, and in fact provided coolant injection for nearly three days [2].There is a current effort being undertaken by the US industry, the US Department of Energy (DOE), and the Government of Japan to investigate the true operating band of the Terry turbopump for BDBE conditions. This paper provides a summary of the experimental and modeling efforts to date.

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Section: Melcor Modeling Effortsmentioning

confidence: 99%

Section: Relap-7 Modeling Effortsmentioning

confidence: 99%

“…INL modified the SNL Terry turbine model [6] and implemented those models into the RELAP-7 code [13]. This effort has been focused on normal working conditions.…”

Section: Relap-7 Modeling Effortsmentioning

confidence: 99%

Section: Relap-7 Modeling Effortsmentioning

confidence: 99%

Section: Relap-7 Modeling Effortsmentioning

confidence: 99%

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