United States Nuclear Regulatory Commission - Protecting People and the Environment

Control of Heavy Loads at Nuclear Power Plants: Resolution of Generic Technical Activity A-36 (NUREG-0612)

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Publication Information

Manuscript Completed: January 1980
Date Published:
July 1980

Preapred by:
H. George, Task Manager, and Members of the A-36 Task Force

Division of Operating Reactors
Office of Nuclear Reactor Regulation
U.S. Nuclear Regulatory Commission
Washington, D.C. 20555-0001

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Abstract

In nuclear power plants heavy loads may be handled in several plant areas. If these loads were to drop in certain locations in the plant, they may impact spent fuel, fuel in the core, or equipment that may be required to achieve safe shutdown and continue decay heat removal. If sufficient spent fuel or fuel in the core were damaged and if the fuel is highly radioactive due to its irradiation history, the potential releases of radioactive material could result in offsite doses that exceed 10 CFR Part 100 limits. If the load damaged equipment associated with redundant safe shutdown paths, the capability to achieve safe shutdown may be defeated. Additionally, if fuel is of sufficient enrichment, the normal boron concentrations that are maintained may not be. sufficient to prevent a load drop from causing the fuel configuration to be crushed and result in criticality.

Task A-36 was established to systematically examine staff licensing criteria and the adequacy of measures in effect at operating plants, and to recommend necescary changes to assure the safe handling of heavy loads. The task involved review of licensee information, evaluation of historical data, performance of accident analyses and criticality calculations, development of guidelines for operating plants, and review of licensing criteria. This report provides the results of the NRC staff's review of the handling of heavy loads and includes the NRC staff's recommeniations on actions that should be taken to assure safe handling of heavy loads. These recommendations include: (1) a program should be initiated to review operating plants against the guidelines developed in Task A-36; (2) certain interim measures should be taken for operating plants until completion of this review program; (3) changes to certain Standard Review Plans and Regulatory Guides should be made to incorporate the guidelines in this report; (4) changes to technical specifications should be made after completion of the review; and (a task should be initated to establish guidelines for the control of small loads near spent fuel. The guidelines proposed include definition of safe load paths, use of load handling procedures, training of crane operators, guidelines on slings and special lifting devices, periodic inspection and maintenance for the crane, as well as various alternatives that include: use of a single failure proof handling system, use of mechanical stops or electrical interlocks to keep heavy loads away from fuel or safe shutdown equipment, or analyzing the consequences of postulated heavy load drops to show these are within acceptable limits.

This report completes Task A-36.

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