Document: NUREG-0800
Document ID: 41b2cf88-b6dc-4005-939a-cf3fb1a561d2
Document Type: srp
Title: INADVERTENT DECREASE IN BORON CONCENTRATION IN THE REACTOR
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0703/ML070380222.pdf
Revision Date: 2023-06
Chapter: 15
Section ID: 15.4.6
CFR Part: 
CFR Title: 

Content:
operation where the SAR states that operator action is needed or expected. 4. When necessary, the reviewer evaluates the effects of single active failures of systems and components that may affect the course of the transient. This phase of the review uses SRP system review procedures for SAR Chapters 5, 6, 7, 8, and 9. In particular, redundant alarms that alert the operator to the unplanned dilution are confirmed. 5. The mathematical models used by the applicant to evaluate core performance and reactivity status are reviewed to determine whether these models have been accepted by staff. If not, a generic review of the model proposed by the applicant is initiated. 6. The staff reviews system parameter values and initial core and system conditions used as input to the model. The reactivity coefficients and control rod worths used by the applicant are of particular importance. The reviewer evaluates the justification provided by the applicant to show that the selected core burnup condition, boron concentration, and rod worths yield the minimum margins. The staff reviews the reactivity parameter values in the applicant's analysis under SRP Section 4.2. The value of core reactivity as a function of time following each analyzed incident is confirmed by comparison to an acceptable analysis for another plant, by comparison to staff calculations for typical plants, or by independent calculations of the reviewer. 7. The assumed dilution flow rates are reviewed, taking into consideration the system parameters acting to limit the flow. The reviewer examines the flow limiting equipment characteristics provided by the applicant to justify flow rate assumptions (e.g., if the flow is limited by the charging pump capacity, the assumed flow is compared to that for all charging pumps acting at full capacity). If a lesser flow value is assumed (e.g., not all pumps operating or flow limited by a valve), justification is necessary. The secondary reviewer is consulted concerning any