Document: NRC Regulatory Guide
Document ID: 626cd346-6298-4966-a92d-c5d4b24bbc2b
Document Type: regulatory_guide
Title: Overhead Crane Handling Systems for Nuclear Power Plants
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1303/ML13038A096.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.104
CFR Part: 
CFR Title: 

Content:
studied and it has been concluded that the travel speed for nuclear power plant application should be conservatively selected. Trolley and bridge speed limits of 30 fpm and 40 fpm, respectively, have been determined to be acceptable. Drivers and Controls. Of the basic types of electric drive motors available for crane operation, the series- wound a.c. or d.c. motors or shunt-wound d.c. motors are readily adaptable to various control systems, and either of these types would be acceptable. Compound- wound motors should not be used because of difficulty in control of the breakdown torque. The horsepower 1.104-3 rating of the driving motor should be matched with the calculated requirement that considers the design load and acceleration to the design hoisting speed. Over- powering of the hoisting equipment would impose addi- tional strain on the machinery and load-carrying devices by increasing the hoisting acceleration rate. A motor rat- ing limited to 110% of the design rating would provide adequate power without loss of flexibility and would be acceptable. Normally, a crane system is equipped with mechani- cal and electrical limiting devices to shut off power to driving motors when the crane hook, trolley, and bridge approach the end of travel or when other parts of the crane system would be damaged if power was not shut off. It is prudent to include safety devices in the control system for the crane, in addition to the limiting devices, for the purpose of ensuring that the controls will return to or maintain a safe holding position in case of malfunc- tion, inadvertent operation or failure, or overspeed and overtorque conditions. Overpower and overspeed con- ditions should be considered an operating hazard as they may increase the hazard of malfunction or inadvertent operation. It is essential that the controls be capable of stopping the hoisting movement within amounts of movement that damage would not occur. A 3-inch maxi- mum hoisting movement would be an