United States Nuclear Regulatory Commission - Protecting People and the Environment

A Study of Control Room Staffing Levels for Advanced Reactors (NUREG/IA-0137)

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Publication Information

Date Published: November 2000

Prepared by:
B. P. Hallbert1, A. Sebok, Institutt for Energiteknikk, OECD Halden Reactor Project
D. Morisseau, U.S. Nuclear Regulatory Commission2

Institutt for Energiteknikk
OECD Halden Reactor Project
P.O. Box 173
N-1751 Halden

1Now with the Idaho National Engineering & Environmental Laboratory
2Now with the Institutt for Energiteknikk, OECD Halden Reactor Project

Prepared as part of:
The Agreement on Research Participation and Technical Exchange
under the International Code Application and Maintenance Program (CAMP)

Office of Nuclear Regulatory Research
U.S. Nuclear Regulatory Commission
Washington, DC 20555-0001

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This report documents the results of an empirical study of operator and plant performance in simulator based settings. The simulator settings were designed to be representative of conventional and advanced plants. The advanced plant design employed passive systems. The control room architectures were also designed to represent both plant types. Two control room staffing configurations were employed in each plant setting: a staffing configuration reflecting the requirements of 10 CFR 50.54 (m); and a staffing configuration that involved a reduced number of control room operators. A series of five design basis scenarios, relevant for both conventional and advanced passive plants were chosen to evaluate the effects of plant type and crew size on operator performance. The scenarios were: 1) steam generator tube rupture with a stuck open steam generator safety relief valve in the affected steam generator, preceded by a fire in the turbine hall; 2) interfacing systems loss of coolant accident with compounded instrument failures due to the incident; 3) sustained total loss of feedwater; 4) loss of off-site power with a single steam generator safety relief valve stuck open, and; 5) steam generator overfill. Eight crews of operators from the Loviisa nuclear power station in Loviisa, Finland participated in the study: four crews in the conventional plant setting; and four crews in the advanced plant setting. Measures of objective performance were obtained, including ratings of crew performance and transient management. Measures of operator workload, situation awareness, and team interaction were obtained repeatedly during each scenario.. The findings of the study revealed a number of effects of crew size and plant type, and their combination on operator performance. This report documents the study and discusses the implications and issues raised by this performance-based evaluation of control room staffing requirements for advanced passive plants.

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