ML20204J484

Requests NRC Review & Approval of CNS ISI Relief Request (RR) PR-04,rev 1.ISI RR PR-04,rev 0 Required CNS to Perform Visual Insp of RPV Head Flange Seal Leak Detection Line. Approval Is Required Because Test Methodology Was Changed

ML20204J484
Person / Time
Site:	Cooper
Issue date:	03/19/1999
From:	Swailes J NEBRASKA PUBLIC POWER DISTRICT
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NLS990028, NUDOCS 9903300101
Download: ML20204J484 (7)

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N Nebraska Public Power District Nebraska's Energy Leader a NLS990028 March 19,1999 U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555-0001 Gentlemen:

Subject:

Inservice Inspection Relief Request, PR-04, Revision 1 Cooper Nuclear Station, NRC Docket 50-298, DPR-46

Reference:

1. Letter (No. NLS950157) to USNRC Document Control Desk from J. H.

Mueller (NPPD) dated October 18,1995, " Third Ten-Year Interval Inservice Inspection Program"

2. Letter to G. R. Horn (NPPD) from J. W. Clifford (USNRC) dated October 23, 1997," Evaluation of the Third Ten-Year hiterval Inspection Program Plan and Associated Requests for Relief for Cooper Nuclear Station (TAC No.

M94000)

The purpose of this letter is to request Nuclear Regulatory Commission (N RC) review and approval of the Cooper Nuclear Station (CNS) Inservice Insrection (ISI) Relief Request (RR) j No. PR-04, Revision 1. The original version of this relief request (hereafter identified as l 1

Revision 0) was previously submitted per Reference I and approved by the NRC per Reference 2.

ISI RR PR-04, Revision 0, required CNS to perform a visual inspection oithe Reactor Pressure Vessel (RPV) head flange seal leak detection line in order to determine the presence of any leakage in the line. The original test was to be performed during Refueling Outage 18 (RFO-M');

however, due to a scheduling error, a pneumatic pressure test of the subject leak detection line was performed instead. This pneumatic test confirmed that no leakage existed, was equivalent ,

to, and met the intent of the test described in Revision 0. Specifically, the use of a pneumatic presst.re test provided the same level ofleak detection capability as flooding up the reactor i cavity. However, NRC review and approval is required because the test methodology was changed. The District requests approval for the alternate methodology, for its recent past use (during RFO-18) as well as for future us.

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NLS990028 t March 19,1999 Page 2 of 3 The alternate methodology usage in lieu of the visual inspection resulted frora a scheduling error.

The need to perform the visual inspection was not identified until after the RPV bolt-up had been completed. Performing the alternate test allowed avoiding an additional RPV bolt-up stress  ;

cycle, which would have resulted from disassembling the vessel head and fboding the vessel cavity.

The scheduling error discovered and the alternate methodology used was discussed between the CNS Nuclear Licensing & Safety Manager, CNS Engineering Support Division Manager, and the NRC Nuclear Reactor Regulation (NRR) Project Manager for CNS. This issue was also presented to the CNS Station Operations Review Committee (SORC) as part of a larger ,

. presentation on ISI issues impacting startup from RFO-18, SORC had determined that the l subject issue did not constitute a startup restraint.

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The followic g corrective actions were completed to address the scheduling error, and the extent i of condition: 1) this inspection was entered into the preventive maintenance tracking system, and  !

2) scheduling and tracking of other ISI requirements were reviewed. No other scheduling or tracking errors associated with ISI requirements were discovered; however, an error related to the specified frequency was discovered in the body of Revision 0.- Even though this relief request  :

correctly referenced the frequency requirements contained in ASME Section XI, Table IWB- I 2500-1 for IWB-5221 tests, the parenthetical information following the frequency specification

. incorrectly specified this frequency as "once each period" instead of"once each refueling outage." The attached information removes the incorrect parenthetical information. The error, described above, resulted in CNS missing the subject inspection during RFO-17. This error was of minimal safety significance and was not reportable per the requirements of 10 CFR 50.72 or 50.73. The alternate inspection performed during RFO-18 demonstrated that the RPV head ,

flange seal leak detection line was capable of containing reactor inventory and was always operable.

' Should you have any questions concerning this matter, please contact me.

Sincerely,

'N c n H.iSwailes V(iceWsident ofEnergy

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Attachment

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NLS990028.' '

March 19,1999 '

Page 3 of 3

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cc: Regional Administrator USNRC RegionIV l- ' Senior Project Manager

! USNRC - NRR Project Directorate IV-1 l- Senior Resident luspector i

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.. 1 Attachment to l NLS990028 Page1of3 i RELIEF REQUEST NUMIFM: PR-04, REVISION 1 COMPONENT IDENTIFICATION I

Code Class: 1

References:

IWB-5210(a)(1)

IWB-5210(a)(2)

Table IWB-2500-1 L,mination Category: B-P Item Numbers: B15.50, B15.51

Description:

Exemption From Pressure Testing Reactor Vessel Head Flange Seal Leak Detection System. e Component Numbers: Line No.1-MS-152-1" l

CODE REOUIREMENTS IWB-5210(a)(1) requires that pressure retaining components following opening and closing l within each system boundary be subjected to a system leakage test after pressurization to l nominal operatmg pressure.

i IWB-5210(a)(2) requires the pressure retaining components within each system boundary to be subjected to a system hydrostatic pressure test.

BASIS FOR RELIEF The Reactor Vessel Head Flange Leak Detection Line is separated from the reactor pressure boundary by one passive membrane, a silver plated 0-ring located on the vessel flange. A second 0-ring is located on the opposite side of the tap in the vessel flange (See Figure PR- .

04.1). This line is required during plant operation in order to indicate failure of the inner I flange seal 0-ring. Failure of the O-ring would result in the annunciation of a High Level

( Alarm in the control room. Upon receipt of this alarm, control room operators would quantify ,

the leakage rate from the 0-ring and then isolate the leak detection line from the drywell sump. I Failure of the inner 0-ring is the only condition under which this line is pressurized, j The configuration of this system precludes hydrostatic testing while the vessel head is removed because the odd configuration of the vessel tap coupled with the high test pressure requirement (1000 psig minimum), prevents the tap in the flange from being temporarily plugged. j

- Adequate testing cannot be performed when the head is installed because the seal prevents complete tilling of the line, which has no available vent.

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l Attachment to i

NLS990028  ;

Page 2 of 3 RELIEF REQUEST NUMBER: PR-04, REVISION 1  !

l BASIS FOR RELIEF (continued.) l Operational testing of this line is precluded because the line will only be pressurized in the event of a failure of the inner 0-ring. It is impracticable to purposely fail the inner 0-ring in order to perfonn a pressure test.

Based on the above, CNS requests relief from the ASME Section XI requirements for static and operational pressure testing of the Reactor Vessel Head Flange Seal Leak Detection System.

PROPOSED ALTERNATE EXAMINATIONS Two equivalent testing methodologies are proposed:

Option 1: A VT-2 visual examination will be performed on the line when the reactor cavity is flooded.

Option 2: As an alternative to Option 1, a pneumatic pressure test at 100 psig will be perfonned.

, The pneumatic test or the hydrostatic head developed due to the water above the vessel flange  !

during refueling outages will allow for the detection of any gross indications in the line.

Option 1 is preferred because it is simple and does not require any additional setup time.

Option 2 provides greater scheduling flexibility because the test can be performed almost anytime during a refueling outage, however, additional radiation exposure is received by l

personnel to remove insulation in order to conduct the test.

i Either of these testing options will be performed with the frequency specified by table IWB-2500-1 for an IWB-5221 test.

APPLICABLE TIME PERIOD Relief is requested for the third ten-year interval of the Inservice Inspection Program.

PR-04, Revision 0 was approved by the NRC on October 23,1997 (TAC No. M94000).

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, Attachment to l NLS990028

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Page 3 of 3 l

RELIEF IEQUEST NUMBER: PR-04 '

FIGURE PR-04.1 i IEAD FLANGE SEAL LEAK DETECTION SCHEMATIC  !

DOUBLE 'O' RING SURFAOE

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-* l ATTAR:HMENT 3 LIST OF NRC COMMITMENTS q l

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.. Correspondence No n- NLS990028 'l l

The following table ider.tifies those actions committed to by the District in this-document. Any other actions discussed-in the submittal represent

' intended or planned actions by the District. They are described to the NRC l for the NRC's information and are not regulatory commitments. Please notify

. the NLES Manager'at Cooper Nuclear-Station of any questions regarding this document or any associated regulatory commitments.

COMMITTED DATE COMMITMENT OR OUTAGE None N/A ,

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PROCEDURE NUMBER 0.42 REVISION NUMBER 6 PAGE 9 OF 13  !

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