Document: NUREG-0800
Document ID: 8b6b2506-1305-4f5c-9cd6-725a1d90c61c
Document Type: srp
Title: CHEMICAL AND VOLUME CONTROL SYSTEM MALFUNCTION THAT RESULTS IN A
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052350402.pdf
Revision Date: 2023-06
Chapter: 15
Section ID: 15.4.6
CFR Part: 
CFR Title: 

Content:
s to the reliable control of reactivity changes to assure that specified acceptable fuel design limits are not exceeded, including anticipated operational occurrences. This is accomplished by assuring that appropriate margin for malfunctions, such as stuck rods, are accounted for. The general objective of the review of moderator dilution events is to confirm that either of the following conditions are met: 1. The consequences of these events are less severe than the consequences of another transient that results in an uncontrolled increase in reactivity and has the same anticipated frequency classification. 15.4.6-2 Rev. 1 - July 1981 2. The plant responds to the events in such a way that the criteria regarding fuel damage and system pressure are met and the dilution transient is terminated before the shutdown margin is eliminated. Specific criteria necessary to meet the relevant requirements of GOC 10, 15, and 26 are as follows: 1. Pressure in the reactor coolant and main steam systems should be maintained below 110% of the design valves. (Ref. 1) 2. Fuel cladding integrity shall be maintained by ensuring that the minimum DNBR remains above the 95/95 DNBR limit for PWRs and the CPR remains above the MCPR safety limit for BWRs based on acceptable correlations (see SRP Section 4.4). 3. An incident of moderate frequency should not generate a more serious plant condition without other faults occurring independently. 4. An incident of moderate frequency in combination with any single active comonent failure, or single operator error, shall be considered and is an event for which an estimate of the number of potential fuel failures shall be provided for radiological dose calculations. For such accidents, the number of fuel failures must be assumed for all rods for which the DNBR or CPR falls below those values cited above for cladding integrity unless it can be shown, based on an acceptable fuel damage model (see SRP Section 4.2), that fewer failures occur. There shall