Document: NUREG-0800
Document ID: a7fafe76-5570-446b-96dd-3e53ec9bccb3
Document Type: srp
Title: NUREG-0800
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052340663.pdf
Revision Date: 2023-06
Chapter: 4
Section ID: 4
CFR Part: 
CFR Title: 

Content:
ntial areas will have been covered during earlier reviews of similar reactors. The reviewer notes any differences in results for essentially identical 4.3-8 Rev. 2 - July 1981 reactors and any lack of differences for reactors with changed core characteristics, and judges the significance and validity of any differences or lack of differences; 4. The review procedures in the area of reactivity control requirements and control provisions are as followt: a. The reviewer determines that two independent reactivity control systems of different design are provided. b. The reviewer examines the tabulation of control requirements, the associated uncertainties, and the capability of the control systems, and determines by inspection and study of the analyses and experimental data that the values are realistic and conservative. c. The reviewer determines that one of the control systems is capable of returning the reactor to the cold shutdown condition and maintain- ing it in this condition, at any time in the cycle. It is necessary that proper allowance be made for all of the mechanisms that change the reactivity of the core as the reactor is taken from the cold shut- down state to the hot, full power operating state. The reviewer should determine that proper allowance is made for the decrease in fuel temperature, moderator temperature, and the loss of voids (in BWRs) as the reactor goes from the power operating range to cold shutdown: d. The reviewer determines that one of the control systems is capable of rapidly returning the reactor to the hot standby (shutdown) condi- tion from any power level at any time in the cycle. This requirement is met by rapid insertion of control rods in all current light water reactors. Proper allowance for the highest worth control rod being stuck in the full-out position must be made. In PWRs, operational reactivity control is carried out by movement of control rods and by adjustments of the concentration o'f soluble poison in the coolant. The