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:
at alert the operator to the unplanned dilution is confirmed. The mathematical models used by the applicant to evaluate core performance and reactivity status are reviewed by RSB to determine if these models have been previously found acceptable by the staff. If not, a generic review of the model proposed by the applicant is initiated. The values of system parameters and initial core and system conditions used as input to the model are reviewed by RSB. Of particular importance are the reactivity coefficients and control rod worths used by the applicant. The justi- fication provided by the applicant to show that the selected core burnup condition, boron concentration, and rod worths yield the minimum margins is evaluated. CPS is consulted regarding the values of the reactivity parameters used in the applicant's analysis. These values are reviewed by CPB under SRP Section 4.2. The value of core reactivity as a function of time following each incident analyzed is confirmed by comparision with an acceptable analysis performed for another plant, by comparison with staff calculations for typical plants done by CPB on request, or by independent calculations by the RSB reviewer. The assumed dilution flow rates are reviewed, taking into consideration the system parameters which act to limit the flow. The reviewer examines the flow- limiting equipment characteristics provided by the applicant to justify his flow rate assumptions; e.g., if the flow is limited by the charging pump capacity, the assumed flow is compared with the flow for all charging pumps acting at full capacity. If some lesser value of flow is assumed, such as not all pumps operating, or flow limited by a valve, justification must be provided. EICSB is consulted concerning any interlocks for which credit is taken. The results of the analyses are reviewed and compared to the acceptance criteria presented in subsection II of this SRP regarding the time available for the operator to take corrective action. The