Document: NUREG-0800
Document ID: c543c347-16c6-4d28-9086-792635d04c4a
Document Type: srp
Title: CONTROL ROD DRIVE SYSTEMS
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052340634.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.9.4
CFR Part: 
CFR Title: 

Content:
ated with plant operations which are expected to occur one or more times during the life- time of the plant and include but are not limited to loss of power to all recirculation pumps, tripping of the turbine generator set, isolation of the main condenser, and loss of all offsite power, combined with loadings caused by natural or accident events including, for BWRs, water hammer loads. The load combinations which are postulated to occur are specified for each of the design and service conditions as defined in Paragraph NB-3113 of the ASME Code (Ref. 7). These load combinations are defined in Reference 12 and are compared by the reviewer with those provided by the applicant. The design stress limits, including fatigue limits, and deformation limits as appropriate to the components of the control rod drive mechanism are compared by the reviewer with those of specified codes, previously designed and successfully operating systems, or with the results of scale model and prototype testing programs. 4. The control rod drive mechanisms of a new design or configuration should be subjected to a life cycle test program to determine the ability of the drives to function during and after normal operating occurrence, seismic, and postulated accident condition over the full range of temperatures, pressures, loadings, and misalignment expected in service. The tests. should include functional tests to determine times of rod insertion and withdrawal, latching operation, scram operation and time, system valve operation and scram accumulator leakage for hydraulic CROS, ability to overcome a stuck rod condition, and wear. Rod travel and number of trips expected during the mechanism operational life should be duplicated in the tests. The reviewer checks the elements of the test program to be sure all required parameters have been included and finally reviews the test results to determine acceptability. Excessive wear, malfunction of components, operating times beyond determined limits,