LR-N970640, Requests One Cycle Deferral for Completing Implementation of Modifications Described in Previous Ltrs Re NRC Bulletin 96-03

Requests One Cycle Deferral for Completing Implementation of Modifications Described in Previous Ltrs Re NRC Bulletin 96-03

ML20217D405
Person / Time
Site:	Hope Creek
Issue date:	09/26/1997
From:	Eric Simpson Public Service Enterprise Group
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
IEB-96-003, IEB-96-3, LR-N970640, NUDOCS 9710030165
Download: ML20217D405 (7)

Text

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, Puble servee Decke and Gas company E. C. Simpson P.O. Box 236. Hancocks Bridge, NJ 08038 009-33M700

% v. % . % ,, l%he Service Doctric SEP 2619 and Gas Compan57 LR-N970640 i

United States Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 DEFERRAL OF IMPLEMENTATION FOR NRC BULLETIN 96-03 HOPE CREEK GENERATING STATION FACILITY OPERATING LICENSE NPF-57

-DOCKET No. 50-354 Gentlemen:

NRC Dulletin 96-03 requested that BWR licensees implement appropriate procedural measures and plant modifications to minimize the potential for clogging of emergency core cooling system (ECCS) suction strainers by debris generated during a loss-of-coolant accident (LOCA). In letters dated November 4, 1996, May 20, 1997 and July 18, 1997, Public Service Electric-&

Gas Company (PSE&G) described the proposed resolution to the issues raised-in the Bulletin.

Due to problems encountered in obtaining the structural steel supports for the replacement ECCS suction strainers, PSE&G is unable to complete installation of the-replacement strainers during the current Hope Creek refueling outage as originally planned. The current refueling outage (RFO7) is scheduled to end November 5, 1997 The next refueling outage is scheduled to begin in mid-February, 1999.

This letter requests a one cycle deferral for-completing the impicmentation of the modifications described in our previous letters.- PSE&G is aggressively pursuing resolution of the issueo that-are delaying installation of the replacement strainers

-during the current outage. The detailed basis for this request is provided in the attachment to this letter.

~Should you have any_ questions _regarding this request, we will be pleased to discuss them-with you.

9710030165 970926

~~

Sincerely,/ '

t PDR ADOCK 05000354 /.

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G PDR_ - g? (>/97 Attachment wd on -

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Document Control Desk SEP 261997 LR-N970640 C Mr. H. Miller, Administrator - Region I U. S. Nuclear Regulatory Commission 475 Allendale Road King of Prussic, PA 19406 Mr. D. Jaffe, Licensing Project Manager - HC i U. S. Nuclear Regulatory Commission  !

One White Flint North 11555 Rockville Pike Mail Stop 14L21 Rockville, MD 20852 Mr. S. Morris (X24)

USNRC Senior Resident Inspector - HC Mr. K. Tosch, Manager IV Bureau of Nuclear Engineering 33 Arctic Parkway PO Box 415 Trenton, NJ 08625 l

t 95-4933

ATTACHMENT 1 DEFERRAL OF IMPLEMENTATION FOR NRC BULLETIN 96-03

Background

NRC Bulletin 96-03 requested that BWR licensees implement appropriate procedural measures and plant modifications to minimize the potential for clogging of emergency core cooling system (ECCS) suction strainers by debris generated during a loss-of-coolant accident (LOCA). In letters dated November 4, 1996, May 20, 1997 and July 18, 1997, Public Service Electric &

Gas Company (PSE&G) described the proposed resolution to the issues raised in the Bulletin.

PSE&G planned to install large capacity passive strainers on the Core Spray and Residual Heat Removal (RHR) system pump suction lines during the current Hope Creek refueling outage, scheduled to end November 5, 1997 The time available to manufacture the replacement strainers was limited due to the lack of an approved technical basis for the resolution of the issues raised in Bulletin 96-03. In order to obtain the replacement strainers in sufficient time to support installation during the current refueling outage, PSE&G specified an expedited delivery schedule. In selecting the supplier for the replacement strainers, PSE&G evaluated the ability of the -

bidders to meet the production schedule.

At the time the contract was awarded, Performance contracting Incorporated (PCI) appeared to have sufficient capacity to meet PSE&G's expedited schedule requirements. The project schedule was based upon delivery of the strainers and all required supports, ready for installation, to PSE&G by September 4, 1997 Installation of the first replacement strainers was scheduled to begin on September 16, 1997 for the B and D RHR and core spray subsystems.

The new ECCS suction strainers are a stacked disk design. Each strainer module is approximately 45 inches in diameter with an active length of about 8 feet. Three strainer modules will be installed on each residual heat removal (RHR) system suction line, and one module will be installed on each core spray (CS) system suction line. The new strainers will be supported by

! structural members attached to the torus miter joint and mid-bay ring girders.

While the strainers are made of stainless steel, the pipe spools used to connect strainer modules and the structural members supporting the new strainers are made of carbon steel and will be Page 1 of 5 i

i Att:chment 1 LR-N970640 '

coated,to minimize corroa. n. The coating is qualified for design basis accident (DBA) conditions in accordance with PSE&G's technical standard for primary containment coatings. The strainer supports are to be prepared for coating in accordance with SSPC SP-5, " White Metal Blast Cleaning."

The replacement ECCS suction strainers are substantially larger than the current Hope Creek strainers and require additional structural support in the torus. There are 26 new structural members required for the replacement ECCS strainers. The first thirteen structural supports did not arrive at the coating applicator's f acility until September 17, 1997 The remaining structural supports were to be shipped to the coating applicator in time to support installation later in the refueling outage.

Reason for Deferral Delay in the installation of the replacement strainers is necessary because of two issues: 1) unacceptable welds on the structural supports; and 2) unacceptable surface conditions for coating the supports.

Inspection of the carbon steel structural supports before coating identified several welds with unacceptable conditions such as are strikes, under cutting, lack of penetration and porosity. The i condition of the welds became apparent only after the support steel was blasted in preparation for coating at the applicator's facility. On September 21, 1997, the first 13 structural supports were shipped back to the fabricator to rework the unacceptable welds. Based upon information provided by Performance Contracting Incorporated (PCI), the supplier of the replacement strainers, the structural support welds will be repaired and the supports will be returned to the coating applicator's facility no earlier than September 30, 1997 The unacceptable condition of the structural support surfaces wr.s not apparent until the support steel was blasted in preparation for coating on September 18, 1997. Mill scale from the rolling process appears to be embedded in the steel surface. Surface grinding has been attempted, but an acceptable surface has not ,

l been obtained to date. The extent of material removal required to obtain a coatable surface is not yet known. PSE&G's specifications required that all carbon steel surfaces be suitably coated for DBA conditions.

! PSE&G and the coating applicator are evaluating the surface condition of the structural supports, but the time required to resolve this issue has not yet been determined. Installation of the replacement strainers cannot be completed during the current Page 2 of 5 l

Atthchment 1 LR-N970640 outage,due to the delays already encountered in obtaining the strainer structural supports.

This deferral is necessary and requested for reasons that were beyond the control of PSE&G.

Basis for Deferral Deferring implementation of the final resolution for one cycle of operation is justified on the basis of: 1) actions previously implemented in response to NRC Bulletin 93-02 and its supplement;

2) actions previously implemented in response to NRC Bulletin 95-

' 02; and 3) implementation of additional compensatory actions proposed here.

1) Bulletin 93-02 and Supplement NRC Bulletin 93-02, " Debris Plugging of Emergency Core Cooling Suction Strainers," dated May 11, 1993, requested licensees to ensure that there were no sources of fibrous material in containment not capable of withstanding a loss of coolant accident (LOCA). In response to the Bulletin, PSE&G performed a design review and concluded that there is no equipment containing fibrous air filters in the Hope Creek primary containment. In addition, containment walkdowns were performed to verify no temporary sources of fibrous material in the containment.

NRC Bulletin 93-02, Supplement 1, " Debris Plugging of Emergency Core Cooling Suction Strainers," dated February 18, 1994, requested licensees to provide training and emergency operating procedures for plant operators and specify alternative wcter sources which may be used te mitigate a strainer blockage event.

PSE&G developed procedures to provide direction to the operator for mitigating the effects of degraded ECCS performance. Training was provided on the Hope Creek simulator clogging.

to demonstrate the indications of ECCS strainer Procedures were revised to provide compensatory actions to prevent, delay or mitigate the loss of available NPSH margin during LOCA conditions.

2) Bulletin 95 02 NRC Bulletin 95-02, " Unexpected Clogging of a Residual Heat Removal (RHR) Pump Strainer While Operating in Suppression Pool Cooling Mode," dated October 17, 1995, requested licensees to take actions necessary to ensure operability of Page 3 of 5

Attachment 1 LR-H970640 the,ECCS with respect to ruppression pool cleanliness and

. foreign material exclusion programs.

In response to Bulletin 95-02, PSE&G performed pump testing and strainer inspections during Hope Creek's sixth refueling outage. During extended core spray and RHR pump operation, there was no reduction in pump suction pressure that would indicate strainer clogging. Video inspection of the strainers after the pump testing showed no significant accumulation of debris. A six inch piece of wire, three 1" x 2" tags and a 0.5" x 0.5" metal object were observed on the strainers.

Suppression pool sludge and water samples were taken. No fibers were detected in the water samples. A small quantity of cloth and fiberglass fibers was found in the sludge samples. The average fiber length was 750 microns. Clogging of the suppression pool suction strainers would not be expected due to the small number and size of the fibers.

In-service testing (IST) procedures were revised to record pump suction pressure at the start and finish of the test to trend pump performance.

The suppression pool was cleaned for the first time since initial plant operation during the fifth refueling outage.

The amount of foreign material found was minimal (a piece of duct tape and a few nuts and bolts). Inspection of the suppression pool during the sixth refueling outage showed little accumulation of debris since the el aning was performed. The cleaning and inspection results confirm the ef fectiveness of Hope Creek's RKE control program.

3) Additional Proposed Compensatory Actions Sludge samples will be taken during the suppression pool cleaning to verify *he absence of fiber accumulation.

The Hope Creek suppression pool is being desludged. This will minimize the potential bulden on the current ECCS suction strainers due to sludge accumulation during the next operating cycle.

A thorough closcout inspection of the drywell and suppression pool (including downcomers) will be performed to verify the thoroughness of suppression pool cleaning and the removal of foreign material, such as maintenance tools and equipment.

Page 4 of 5

Atthchment 1

• LR-N970640 Conclusion The proposed compensatory actions, together with the actions already taken, provide reasonable assurance of continued safe operation with the existing ECCS suction strainers.

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