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:
de before and after the test and should be fol- lowed by a nondestructive examination that should con- sist of combinations of magnetic particle, ultrasonic, radiograph, and dye penetrant examinations to verify the soundness of fabrication and ensure the integrity of this portion of the hoisting system. The results of exami- nations should be documented and recorded for the hoisting system for each overhead crane. h. Means should be provided to sense such items as electric current, temperature, overspeed, over- loading, and overtravel. Controls should be provided to absorb the kinetic. energy of the rotating machinery and ,stop the hoisting movement within a maximum of 3 inches of vertical travel through a combination of elec- trical power controls and mechanical braking systems and torque controls if one rope or one of the dual reev- ing system should fail or if overloading or an overspeed condition should occur. i. The control systems should be designed as a combination of electrical and mechanical systems and may include such items as contactors, relays, resistors, and thyristors in combination with mechanical, devices and mechanical braking systems. The electric controls should be selected to provide a maximum breakdown torque limit of 175% of the required rating for a.c. motors or d.c. motors (series or shunt wound) used for the hoisting drive motor(s). Compound wound dcc. motors should not be used. The control system(s) pro- vided should include consideration of the hoisting (raising and lowering) of all loads, including the maxi- mum design rated load, and the effects of the inertia of the rotating hoisting machinery such as motor armature, shafting and coupling, gear reducer, and drum. j. The mechanical and structural components of the complete hoisting system- should have the re- quired strength to resist failure if the hoisting system should "two block"1I or if "load hangup" 2 should occur during hoisting. The designer should provide means within the