Document: NUREG-0800
Document ID: efac696f-0049-4b65-b562-4a813c1d817c
Document Type: srp
Title: STANDBY LIQUID CONTROL SYSTEM (BWR)
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070538.pdf
Revision Date: 2023-06
Chapter: 9
Section ID: 9.3.5
CFR Part: 
CFR Title: 

Content:
jection rate is sufficient to bring the reactor from rated power to cold shutdown at any time in core life with the control rods remaining withdrawn in the rated power pattern, taking into account the reactivity gains from complete decay of the rated power xenon inventory, an allowance for imperfect mixing and leakage, and dilution by the residual heat removal system. d. To verify compliance with relevant ATWS rule requirements, SRXB determines that the system has the capability of injecting into the reactor pressure vessel a borated water solution at such a flow rate, level of boron concentration and boron-10 isotope enrichment, and accounting for reactor pressure vessel volume, that the resulting reactivity control is at least equivalent to that resulting from injection of 326 Lpm (86 gpm) of 13 weight percent sodium pentaborate decahydrate solution at the natural boron-10 isotope abundance into a 638-cm (251-in) inside diameter reactor pressure vessel for a given core design. The requirement allows flexibility in its implementation; i.e., the equivalence can be obtained by increasing flow rate, boron concentration or boron enrichment. The important parameters considered in establishing equivalence are the vessel boron concentration required to achieve shutdown and the time required to achieve that vessel boron concentration (see Generic Letter 85-03). The SRXB reviewer evaluates the system arrangement and associated features, including the injection location(s), to determine that they will facilitate reliable, undiverted injection of borated solution to the reactor vessel. For BWRs that are required to provide automatic SLCS initiation under the rule, the SRXB reviewer coordinates with HICB as described in subsection I to also verify that the system has acceptable provisions for automatic initiation.40 e. The system P&IDs indicate that adequate means are provided to maintain the system temperature above the saturation temperature of the neutron absorber solution.