NRC Generic Letter 1980-54

NRC Generic Letter 1980-054: Transmittal of IE Bulletin 1980-014, Degradation of BWR Scram Discharge Volume Capability.

ML031350403
Person / Time
Issue date:	06/12/1980
From:	Engelken R H NRC Region 4
To:	Jacobson G W
References
BL-80-014 GL-80-054, NUDOCS 8007140418
Download: ML031350403 (4)

-t I.,4UNITED STATES -- -NUCLEAR REGULATORY COMMISSIONREGION V1990 N. CALIFORNIA BOULEVARDSUITE 202. WALNUT CREEK PLAZAWALNUT CREEK, CALIFORNIA 94596eFA -IJune 12, 1980G L7 --I Q~ 4 '(-Docket Nos. 50-522, 50-523Puget Sound Power & Light CompanyPuget Power BuildingBellevue, Washington 98009Attention:Mr. G. W. JacobsenProject Manager -NuclearGentlemen:The enclosed IE Bulletin No. 80-14 is forwarded to you for information.No written response is required. If you desire additional informationregarding this matter, please contact this office.Sincerely,R. H. EngelkenDirectorEnclosures:1. IE Bulletin No.80-142. List of Recently IssuedIE Bulletins800714 019W

SSINS No.: 6820Accession No.:UNITED STATES 8005050056NUCLEAR REGULATORY COMMISSIONOFFICE OF INSPECTION AND ENFORCEMENTWASHINGTON, D.C. 20555June 12, 1980IE Bulletin No. 80-14DEGRADATION OF BWR SCRAM DISCHARGE VOLUME CAPABILITYDuring our review of BWR operating experience, two events have raised concernon operations related to the control rod drive system scram discharge volume(SDV).

Description of Circumstances

At Hatch Unit 1, on June 13, 1979, while performing surveillance to func-tionally test SDV high level switches, two switches (C11-NO13A, B) were foundto be inoperable. Redundant switches (C11-N013 C, D) were operable. Thereactor was in the refuel mode and these switches had been modified prior tothis occurrence. Inspection of the inoperable level switches revealed thatthe float rod was bent and binding against the side of the float chamber onboth switches. The licensee believes that the float rods were bent during orprior to initial installation and that metal particles from the modificationcaused binding of the float. (LER 79-038)Brunswick Unit 1 reported that slow closure of the SDV drain valve during areactor scram on October 19, 1979 apparently caused a water hammer event whichdamaged several pipe supports on the SDV drain line. Drain valve closure timewas approximately five minutes due to a faulty solenoid controlling air supplyto the valve. The damaged pipe supports were repaired but repair parts forthe faulty solenoid were not available. To prevent possible damage from ascram, the unit started up with the SDV vent and drain valves closed exceptfor periodic draining. During this mode of operation the reactor scrammedfrom high level in the SDV, without prior actuation of either the high levelalarm or rod block switch. Subsequent inspection revealed that the float ballon the rod block switch was crushed and the float ball stem on the high levelalarm switch was bent such that the switches would not operate. The waterhammer event discussed above was the reported cause of failure of these twoswitch assemblies. (LER 79-74)As a result of these events and related anticipated transients without scram(ATWS) studies, concern arises that the SDV function may be degraded by theundetected presence of fluid in the SDV. The second event is significant inthat it indicates the potential for a common cause failure (faulty solenoid)to result in operation of the SDV in a manner which could defeat both thelevel switch function and the SDV draining function. The ATWS generic studies(NUREG 0460) have led the staff to propose, among other requirements, improve-ments in the SD' designs to reduce susceptibtifty to comion cause failures.By separate correspondence, the staff will provide example Technical Specifica-tions related to the action items discussed below.

IE Bulletin No. 80-14 June 12, 1980 A. GE BWR's With an Operating LicenseThe following actions are to be taken by licensees of GE designed BWRfacilities with an operating license:1. Review plant records for instances of degradation of any SDV level switchwhich was or may have been caused by a damaged or bent float assembly.Identify the cause and corrective action for each instance.2. Review plant records for instances of degradation of SDV vent and drainvalve operability. Provide the closure times required and typicallyobserved for these valves and the basis for the required closing times.Identify the cause and corrective action for each instance of degradation.3. By procedures, require that the SDV vent and drain valves be normallyoperable, open and periodically tested. If these valves are not operableor are closed for more than 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> in any 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> period during operation,the reason shall be logged and the NRC notified within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> (PromptNotification).4. Review instances in which water hammer or damage which may have beencaused by water hammer has occurred in SDV related piping. Identify thecause and corrective action for each instance.5. Review surveillance procedures to ensure that degradation of any SDVlevel switch due to a damaged float or other cause would be detected andthat inoperability from any cause would be reported to the NRC.6. If no functional test or inspection which would detect degradation ofeach SDV level switch has been performed during the past 3 months, makeprovisions to perform an inspection and functional test of all SDV levelswitch assemblies at the next reactor shutdown of greater than 48 hour5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />sduration.B. Reporting RequirementsThe action taken in response to the items in Part A shall be completedand a written report on the results submitted to the NRC within 45 daysfrom the date of this Bulletin.This report should be submitted to the Director of the appropriate NRC RegionalOffice and a copy should be forwarded to the NRC Office of Inspection andEnforcement, Division of Reactor Operations Inspection, Washington, D.C.20555.Approved by GAO, B180225 (R0072); clearance expires 7-31-80. Approval wasgiven under a blanket clearance specifically for identified generic problems.

-*IE Bulletin No. 80-14June 12, 1980EnclosureRECENTLY ISSUEDIE BULLETINSBulletinNo.80-13SubjectCracking In Core SpraySpargersDate Issued5/12/80Issued ToAll BWR's with anOL80-1280-1180-1080-0980-0880-0780-0680-0579-OiB80-04Decay Heat Removal SystemOperabilityMasonry Wall DesignContamination ofNonradioactive System andResulting Potential forUnmonitored, UncontrolledRelease to EnvironmentHydramotor ActuatorDeficienciesExamination of ContainmentLiner Penetration WeldsBWR Jet Pump AssemblyFailureEngineered Safety Feature(ESF) Reset ControlsVacuum Condition ResultingIn Damage To Chemical VolumeControl System (CVCS) HoldupTanksEnvironmental Qualificationof Class IE EquipmentAnalysis of a PWR MainSteam Line Break WithContinued FeedwaterAddition5/9/805/8/805/6/804/17/804/7/804/4/803/13/803/10/802/29/802/8/80Each PWR with an OLAll power reactorfacilities with anOL, except TrojanAll power reactorfacilities with anOL or CPAll power reactoroperating facilities andholders of power reactorconstruction permitsAll power reactors witha CP and/or OL no laterthan April 7, 1980All GE BWR-3 andBWR-4 facilities withan OLAll power reactorfacilities with an OLAll PWR power reactorfacilities holdingOLs and to those witha CPAll power reactorfacilities with an OLAll PWR reactor facilitiesholding OLs and to thosenearing licensing