ML20024H090

LER 91-007-00:on 910410,handling of Control Rod Prohibited by Tech Spec Surveillance Requirements 4.9.6.3b.Caused by Inadequate Procedure.Maint Procedure Changed Deleting Provisions to Reposition Mechanical stop.W/910510 Ltr

ML20024H090
Person / Time
Site:	Limerick
Issue date:	05/10/1991
From:	Doering J, Madsen G PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-91-007-02, LER-91-7-2, NUDOCS 9105210239
Download: ML20024H090 (6)

Text

{{#Wiki_filter:- - - . . . . = 10 CFR 50.73

 ,                            PHILADELPHIA ELECTRIC COMPANY LIMERICK GENER ATING ST ATION P. O. DOX A S AN ATOG A. PENNSYLV ANI A 19464 l215) 3271200 mar,2000

3. ooc o m o. s n. May 10, 1991 PhA , MehA6 9 Docket No. 50-353 License No. NPF-85 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555

SUBJECT:

Licensee Event Report Limerick Generating Station - Unit 2 This LER reports a condition of the refueling platform monorail mounted auxiliary hoist where operation of the uptravel mechanical stop permitted the handling of a control rod ou',shie the limits of Technical Specifications due to procedurt: deficiencies.

Reference:

Docket No. 50-353 Report Number: 2-91-007 Revision Number: 00 Event Date: April 10, 1991 Report Date: May 10, 1991 Facility: Limerick Generating Station P.O. Box A, Sanatoga, PA 19464 This LER is being submitted pursuant to the requirements of 10 CFR 50.73(a)(2)(1)(B). Very truly yours, T

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Limerick Generating Station, Unit 2 0 l5 l 0 l0 l 0 l3 i i l3 Handling of a control rod prohibited by Technical Specifications Surveillance 1 lodo 15_ Requirements 4.9.6.3b due to procedure deficiencies.

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                                                                            $UPPLEME NT AL htPQR T f uPE CTt o 414-                                                                         YONT*      CAV     vtan Sv8M*5$4N Yt $ I!9 vos comonore it9fCTIO Sv0V?$$sCN CA TtJ                                         %Q l         l       l GCET R ACT ILet to tex noeces o e acerosometew *droen son,p e socco riosone**n ew (1er On April 10, 1991, a Fuel Handling Supervisor observed the uptravel mechanical stop on the refueling platform monorail mounted auxiliary hoist to be mispositioned outside the limits of Surveillance Test procedure ST-6-107-633-2,
                              " Core Alteration Testing." During the previous shift the uptravel mechanical stop was moved 24 inches to permit movement of a control rod blade from the spent fuel pool to the reactor. On April 12, 1991, dJring investigation into the event, it was determined that the top of a control rod blade was Ic5 inches less tnan the required 6 feet 6 inches below the normal fuel storage pool water level; a condition prohibited by Technical Specifications (TS) Surveillance Requirement (SR) 4.9.6.3b. TS SR 4.9.6.3b was amended on August 16, 1990. Prior to August 16, 1990, the interpretation of TS SR 4.9.6.3b did not limit control rod blade movement. The cause of this event was an inadequate maintenance procedure M-041-061 and an inadequate procedure ST-6-107-633-2. A contributing cause to the event was inadequate training of the fuel Handling Supervisors on invessel maintenance activities following the change to TS SR 4.9.6.3b. The maintenance procedure has been changed to delete the provision to reposition the mechanical stop. Procedure ST-6-107-633-2 has also been revised. Additionally, the appropriate requalification training programs will be revised, the TS amendment control procedure will be revised and previously issued TS amendments will be reviewed to determine if a similar problem occurred.

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NACFesm 3s6& W.5 NUCLE AR REGUL ATORY COMMstsiO4 LICENSEE EVENT REPORT..(LER) TEXT CONTINUATION __ anaovio ous No. mo.o* E X PfR 45:8138/85 F ACateTY N AME 111 00CR41 Nuwste al gg , ggggg , gg, i

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                          .           .--.a nac i m m Unit Conditions Prior to the Event:

Unit 2 Operational-Condition was 5 (Refueling) at 0% Power Level. There were no structures, systems or components out of service or being tested  ;

           . which contributed to this event.                                                                                                                               !

Description of the Event: On April- 10, 1991, at.1630 hours, a utility employed, licensed Fuel Handling Supervisor observed the uptravel mechanical stop on the refueling platform monorail mounted auxiliary-hoist to be mispositioned outside the limits of Surveillance Test (ST) procedure ST-6-107-633-2, " Core Alteration Testing." An investigation was initiated to determine if Technical Specifications (TS) Surveillance Requirement (SR) 4.9.6.3b was violated. TS SR 4.9.6.3b requires demonstrating operation of.the uptravel mechanical stop on the monorail hoist when uptravel brings the top of.a control rod to.not less than 6 feet 6 inches below the normal fuel storage-pool water level. This SR is required to be performed within seven days prior to the use of such equipment. On April 9, 1991, procedure-ST-6-107-633-2 was performed to ensure compliance-with TS SR 4.9.6.3b prior to control rod blade (CRB) movement. Procedure ST 107-633-2 sets the mechanical stop to ensure the loose end of the hoist cables, with-no tools attached, will remain at least 5 feet below the surface of the water. With an invessel tool attached, the distance-from the hoist cable loose end to the top of the CRB bail handle provides the other 18 inches necessary to i meet the 6 feet 6 inch.TS SR. The actual distances provided are 19.875 inches by the CRB grapple 20.5 inches-by the jet pump grapple, and 39.5 inches by the

           . control rod bladeLlatch tool (Figure 1). A CRB can be transferred between the reactor vessel and the spent fuel. pool following performance of procedure ST               107-633-2 using the CRB grapple or jet pump grapple but not by using the CRB latch tool. While the CRB grapple and jet pump grapple provide 9.125 inches of clearance from the bottom of the CRB to the transfer canal (cattle chute) floor, the CRB latch tool extends-the bottom of the CRB 10.25 inches below the transfer canal floor.

On April- 10. 1991 at 1240 hours, the mechanical stop was moved 24 inches to , transfer a CRB from the spent fuel pool to the reactor vessel using the CRB latch tool. This resulted in the top of the CRB being 6 feet 3.5 inches below the surface of the water in violation of TS SR 4.9.6.3b. At shift turnover on April 10, 1991, at 1630' hours the oncoming, a licensed Fuel Handling Supervisor

           .-observed the uptravel mechanical stop to be mispositioned.. The mechanical stop was reset and procedure ST-6-107-633-2 was performed to verify compliance with TS SR 4.9.6.3b.

On April 12, 1991, during investigation into this event, the ectual measurements of the hoist cable and the tools and the distance that the mechanical stop was l moved were obtained and analyzed. Station personnel then determined that the TS

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NIC Fe** 3 4A U s NUCtt An REGut& TORY COMMitsiON i - LICENSEE EVENT REPORT (LER) TEXT CONTINUATION arraono oms =o mo-oio. Smals se3m P Acessiv N AMt (11 POC A11 NUMa t R t3' tta NUMBER 16e PAGE(31 "a "20 W. *'4*.U Limerick Generating Station, Unit 2 o s jo jo li 3l5l3 9l1 - 0l0l7 - 0]O 0l3 OF 0 l5 rtn w-, e-..,.,-a.. .ae,. ,o u m .mn SR 4.9.6.3b was not met and the action of TS 3.9.6, suspension of handling CRB's, was not complied with. This resulted in a condition prohibited by TS. This report is being submitted in accordance with the requirements of 10CFR50.73(a)(2)(i)(B). Analysis of the Event: The consequences of this event were minimal. There was no release of radioactive material to the environment as a result of this event. A t al radiation survey meter in use did not register any change in area radiation levels during this event. Any increased radiation dose to the operators from a 2.5 inch reduction in water shielding was of a limited duration. The dosimetry of the operators was checked and the radiation exposure was found to be similar to that collected on previous shifts. The possible consequences from this event was bounded by the fuel handling accident discussed in section 15.7.4 of the Updated Final Safety Analysis Report (UFSAR). Fuel handling personnel reset the mechanical stop and performed procedure ST-6-107-633-2 to verify compliance with TS SR 4.9.6.3b and limit-the event duration. Cause of the Event: The cause of the event was an inadequate maintenance procedure M-041-061,

          " Unlatching and Shuffling of Control Rod Blades," and an inadequate ST procedure ST-6-107-633-2. Procedure M-041-061 allowed adjustment of the mechanical stop to raise a CRB to clear the transfer canal floor without identifying the maximum amount of adjustment permitted. Procedure ST-6-107-633-2 positioned the mechanical stop at the same height irrespective of the tool to be used to move a CRB even though the height position was unsuitable for the tool normally used to move blades between the spent fuel pool and the reactor vessel (i.e. the CRB latchtool). A contributing cause to the M-041-061 procedure deficiency was a failure of the Licensing group to notify maintenance that TS SR 4.9.6.3b was amended on August 16, 1990, which changed the limit for handling CRB's.

A contributing cause to the event was inadequate training of the licensed Fuel Handling Supervisors on invessel maintenance activities (those maintenance activities carried out inside the reactor vessel that are not core alterations) following the August 16, 1990 change to ST SR 4.9.6.3b. Prior to August 16, 1990, the interpretation of the operability requirement for the mechanical stop did not limit CRB movement. TS SR 4.9.6.3b originally limited the uptravel of the top of active fuel to eight feet six inches below the fuel pool water !c el while UFSAR section 9.1.4.3 analyzes CRB movement with seven feet of water shielding. After August 16, 1990, the training provided to the licensed Fuel Handling Supervisors did not adequately explain this change and the impact in CRB movement. Additionally, the adequacy of compliance with TS SR 4.9.6.3b after August 16, 1990 , was not determined by either the plant staff self assessment or by Nuclear Quality Assurance (NQA) Department.

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0l0l7 -- 0l0 0l4 or 0 l5 T m m . ., -.A .. - - c, - On Insufficient evidence exists to determine if TT Sr 1.3.A.3h was violated between August 16, 1990, and April 9, 1990. Corrective Actions: The mechanical stop was reset and procedure ST-6-107-633-2 was performed to verify compl'iance with TS SR 4.9.6.3b. The plant Manager issued a letter on April 11, 1991, forbidding further adjustment of the mechanical stop until authorized by the Plant Manager or his designated alternate. Procedure M-041-061 was revised on April 19, 1991, to delete the provision that permitted repositioning of the mechanical stop. CRB movement from the spent fuel pool to the reactor vessel was completed using the CRB grapple which allows CRB passage through the transfer canal without mechanical stop adjustment. Procedure ST 107-633-2 has been revised to set the mechanical stop for the CRB latch tool at an appropriate height that is different from the height necessary for the CRB and jet pump grapple. The TS Amendment issued on August 16, 1990, was included in Licensed Operator required reading in October, 1990, but no training was provided to fuel Handling Supervisors on TS SR 4.9.6.3b. Invessel maintenance activities will be included in initial and requalification training of licensed fuel handling supervisors. In order to ensure that there were no similar problems occurred related to inadequate communication and review of TS amendments involving refueling and in-vessel maintenance activities, all TS amendments issued from August, 1990, to the present were reviewed. No additional TS amendment was found to affect any refueling or invessel maintenance activity. Administrative procedure A-29,

        " Control of Revisions Due to License Document Revisions," will be revised by July 31, 1991, so that all affected organizations will be notified of future amendments so that all effected procedures are revised. Additionally all TS amendments implemented since issuance of the Unit 2 license wi Te reviewed to identify any deficiencies in implementation. Administrative                        ine AG-82, "Self Assessment," will be revised by July 31, 1991 to requi <                     r procedure and program changes to be the subject of self-assessment with.n the same self assessment cycle. Procedure A-29 will also be reviewed to provide copies of all future TS amendments to the HQA Department. The HQA Department will review the change and perform an appropriate review of the implementation _of the TS amendment.

Previous Similar Occurrences: None Tracking Codes: 02 - Inadequate procedure did not cover situation A99 - Other personnel errors gc .o . ..

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