NRC Generic Letter 1985-03
| ML031150576 | |
| Person / Time | |
|---|---|
| Issue date: | 01/02/1985 |
| From: | Eisenhut D G Office of Nuclear Reactor Regulation |
| To: | |
| References | |
| GL-85-003, NUDOCS 8501290633 | |
| Download: ML031150576 (1) | |
1__.-.. e t norl* A-dIudry 1Y oTO ALL BOILING WATER REACTOR LICE SEES AND APPLICANTSGentlemen:SUBJECT: CLARIFICATION OF EQUIVALENT CONTROL CAPACITY FORSTANDBY LIQUID CONTROL SYSTEMS (Generic Letter 85-03)3Paragraph (c) (4) of 10 CFR 50.62 states, in part:Each boiling water reactor must have a standby liquid controlsystem (SLCS) with a minimum flow capacity and boron contentequivalent in control capacity to 86 gallons per minute of13 weight percent sodium pentaborate solution.The "equivalent in control capacity" wording was chosen to allow flexibilityin the implementation of the requirement. For example, the equivalence canbe obtained by increasing flow rate, boron concentration or boron enrichment.The 86 gallons per minute and 13 weight percent sodium pentaborate were valuesused in NEDE-24222, "Assessment of BWR Mitigation of ATWS, Volumes I and II,"December 1979, for BWR/4, BWR/5 and BWR/6 plants with a 251 inch vessel insidediameter. That different values would be equivalent for smaller plants wasrecognized in NEDE-24222:The flow rates given here are normalized from a 251-inch-diametervessel plant to a 218-inch-diameter vessel plant, i.e., the 66GPM control liquid injection rate in a 218 is equivalent to 86GPM in a 251. This is done to bound the analysis...(pp. 3-12)The important parameters to consider in establishing equivalence are vesselboron concentration required to achieve shutdown and the time required toachieve that vessel boron concentration. The minimally acceptable systemshould show an equivalence in these parameters to the 251 inch diametervessels studied in NEDE-24222.There are no reporting requirements associated with this generic letter.
Sincerely,Original signed byDarrell G. EisenhUtDarrell G. Eisenhut, DirectorDivision of LicensingOffice of Nuclear Reactor RegulationOELD 144VWShieldsORAL 1/23/85/ORAMA :DL A E DTAlexb m. JHannon Holahan DCru chfield D X nhn$ u1/10 1/13/85 1/t0 /85 1/1(/85 1 ,/85t5oh74oe633