ML20101Q617

TS Change Request 92-07-2 to License NPF-85,changing TS 3.6.3 Re Primary Containment Isolation Valves to Relocate Approx 1,300 Individual Hydraulic Control Unit Isolation Boundaries on Common CRD Headers

ML20101Q617
Person / Time
Site:	Limerick
Issue date:	07/07/1992
From:	Beck G PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20101Q620	List: ML20101Q617 ML20101Q623
References
NUDOCS 9207150032
Download: ML20101Q617 (8)

Text

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10 CFR 50.90

- PIHLADELPIIIA ELECTRIC COMPANY NUCLEAR GROUP llEADQUARTERS 955-65 CllESTERBROOK BLVD.

WAYNE, PA 19087 5691 (215) 640-6000 July 7, 1992 PWCLEAR FNGINEERING & SERVICES DEPARTMENT Docket No. 50-353 License No. NPF-85 c

U. S. Nuclear Regulatory Commission

-ATTN: Document Control Desk Washington, DC 20555

SUBJECT:

Limerick Generating Station, Unit 2 Technical Specifications Change Request Gentlemen:

Philadelphia Electric Company is submitting Technical Specifications Change Request.(TSCR) No. 92-07-2, in accordance with 10 CFR 50.90, requesting an c amendment to the Technical Specifications (TS) (Appendix A) of Operating License

'No NPF-85. Information supporting this Change Request is contained in

. Attachment.1 to this letter, and the proposed replacement pages are contained in LAttachment 2.

This submittal requests changes to TS Secticn 3.6.3, " Primary Containment Isolation Valves," to. relocate the approximately thirteen hundred (1300)

-individuLal Hydraulic Control Unit NCU) isolation boundaries by installation of

'four.new isolation boundary valves on the common Control Rod Drive (CRD) headers. This'same change was approved by the NRC for Unit 1 by TS Amendment No.-.42, dated August 16, 1990. ._

If_you have any questions regarding this matter, please contact us.

Very truly yours, g[

G. J< Beck, Manager Licensing Section

.y Attachments-cc: LT. T. Martin, Administrator, Region I, USNRC, w/ attachments T. J. Kenny, USNRC Senior Resident Inspe: tor, LGS w/attacnments W. P. Cornsife,-Director, PA Bureau of Radiological Protection w/att.

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• C0ljNTY OF CHESTER: -

- D. R. Helwig, being first duly sworn, deposes ar.d says:

That he is" Vice' President of Philadelphia Electric Compar.y; the

' Applicant herein;fthat be has read the foregoing Application for Amendment ~-

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k - of. Faci 1ity.0perating License-No_. NPF-85 (Technical Specifications Change Request No'. 92-02-7) to relocate-the Ilydraulic Control Unit (HCU)

-isolation' boundaries;-and knowsLthat the contents thereof; and that the L

- statements';-and matters set forth therein are true and correct to the best (of his; knowledge,;information and belief. _

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ATTACHMENT 1 i

m LIMERICK GENERATING STATI0d Unit 2 L

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-Docket No. 50-353 >

License No. NPF-85

-TECI!NICAL' SPECIFICATIONS CHANGE REQUEST No. 92-07-2

" Proposed Changes to.the Technical Specifications to

' Relocate the Hydraulic Control Unit (HCU) Isolation Boundaries"  ;

, . Supporting Information for Changes pages-

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i Philadelphia Electric Company (PECo), Licensee under Facility Operating License No. NPF-85 for Limerick Generating Station (LGS), Unit 2, requests that the-' Technical Specifications (TS) contained in Apoendix A to the Operating License be amended as proposed herein to reflect newly installed isolation valves on each common Control Rod Drive (CRD) header and to eliminate the existing individual Hydraulic Control Unit (HCU) isolation boundaries from TS.

The proposed. changes to the TS are indicated by the vertical bars in the margin of the TS pages 3/4 6-23 and 3/. 6-41. TS page 3/4 6-43 is included for infarmation. All TS pages are contained in Attachment 2.

This same change was approved by the NRC for LGS Unit 1 in TS Amendment No.

42, dated August 16, 1990. Pe request the changes proposed herein to be effective by February 28, 1993, to facilitate incorporation and use for the scheduled cont 6inment integrated leak rate test during the upcoming Unit 2 refueling outage scheduled to begin January 23, 1993.

This change equest provMes a di' ission and description of the proposed

-TS changes, a safety assessment of the proposed TS changes, information supporting a-finding of No Significant Pazards Consideration, and information -

supporting _ an Environmer:tal Assessment.

Discussion'and Description of the Proposed Changes The Integrated Leak Rate Test (ILRT) is a pressurization of pr mary i containment and measurement of total leakage from all isolation boundaries.

This test bv its nature is a critical path task during a Ref eling Outage. The current me Uod of testing the isolation boundaries of the CRD system is to collect leakage through-the HCus at thu vent valves on each of four supply headers during an ILRT. If the total leakage exceeds specified limits,

'approximately 1300 individual check valves or solenoid valves must be examined to find and repair leak paths. .The process of identifying the leaking valve (s) can take many days of critical path outage time.

To minimize critical path outage time, new check valves will be installed in the CRD supply headers.in four locations, effectively extending the isolation 4 boundary from the HCUs to these new valves (See Figure 1). These four (4) new h valves will reduce the number of testable CRD penetrations from approximately 1300 to four.

Although a TS change is not required prior to installation of the new valves, a TS change _is required te take credit for these new isolation boundaries, and also to remove the current valve numbers for the HCU isolation boundaries from TS. Therefore, we propose that TS Table 3.6.3-1, "Part A-Primary Containment- Isolation Valves," be revised to remove the existing HCU isolation boundary valves and replace them with the newly installed isolation boundary valves. Note 12 of that table should also be revised as shown in Attachment 2 tu reflect the addition o' the new valves. -Also, since the affected CRD lines are water filled and would remain water filled for a minimum of thirty days after a loss of Coolant Accident (LOCA), Note 22 applies to these isolation valves.

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-Safety Assessment-The current primary containment isolation design for the CRD insert and withdraw lines does not conform to 10CFR50, Appendix A General Design Criterion (GDC) 55, " Reactor coolant pressure boundary penetrating containment," because of the system's uniqueness of design, inherent safety features, and important safety function. -The system was analyzed against GDC 55 requirements on a General Electric (GE) and found acceptable by the NRC as cited generic basis by' Generic Safety Evaluation Report Regarding Integrity of BWR in NUREG-0803,

-Scram System Piping." The_ existing-isolation pro W ions for the CRD insert and

- withdraw lines at LGS Units 1 and 2 were found acceptable by the NRC as documented in LGS Sa'ety Evaluation Report (SER) (NUREG-0991) Section f.2.4.1, dated August, 1983. The present method of leakage monitoring was accepted by

-the NRC in SER-Section 6.2.6.3.

-The new design does not change the design criteria described above but enhances our ability to demonstrate the leak integrity of the existing analyzed design configuration. The testing of the new valves uses techniques and cr_iteria accepted for other similar applications as documented in the LGS Updated Final Safety Analysis' Report (UFSAR) Table 6.2-25, " Containment Penetrat bns - Compliance with 10CFR, Part 50, Appendix J," Note 14.

The proposed.TS change will take credit for the new check valves installed

.in each of the CRD headers to the HCUi; (i.e., drive, cooling, charoing, and exhaust) between the main control station and the vent valve. These valves constitute a new isolation boundary. Each check valve station consist of two eneck valves, a block valve and two test connections. This enables each check valve.to be tested individually instead of during the. critical path-ILRT. A new access platform has been installed in order to facilitate local testing of the added check valves. The new platform was designed to the American Institute of Steel Construction _(AISC) and Seismic Category ; requirements.

-An analysis has-been performed on t - aiping being upgraded for inclusion in the-extended ILRT boundary. The pipit and related pipe supports are designed to meet the criteria of Seismic Category I and American Society.of Mechanical Engineers'(ASME) Boiler and Pressure Vessel Code-Section III, Class 2 or'3 as appropriate. Analysis has shown that the existing piping and the modified piping is within the'ASME Code allowables. Piping supports have been evaluated and modified as necessary to accommodate the newly analyzed-loads.

Mechanical environmental qualification of the check valves has been evaluated and confirmed to be acceptable. Dynamic-qualification of each check valve and its mounting has been evaluated and confirmed to be acceptable. The valves that will be used for this modification have been used extensively at LGS Lin similar applications.

The hydraulic effect of'the-new valves has been evaluated. The most critical and limiting case is the cooling water header required to supply 50-60 gpm to the CRDs during normal operation. The exhaust header performs a pressure control function and normally has no flow. The pressure control function does not have a critical time-component so flow resistance is not an issue. The drive _ water header has flow only_ during rod movement and ther, only

.four (4) gpm. The charging header supplies pressure to the HCUs. The only.

operation requiring significant flow is after reactor scram or during initial HCU charging when time is not a critical parameter.

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At a cooling water flow rate of 55 gpm, the pressure drop through the chec.k valves will, therefore, be 1 psi cach and 0.8 psi through the globe valve. The tota'l for each valve station,-including line losses, will be approximately 3.1

- psi.

In order to compare the calculated pressure drop with the available system pressure, data was obtained from the plant. A test was performed simulating the additional system resistance by adding approximately an 8 psi pressure drop and the effect on system performance was measured. We have determined that the simulation of an additional 8 psi pressure drop can be compensated for by the system with no reduction in cooling water flow rate. Therefore, the 3 psi additional loss asst Jiated v.ith the installation of the new valves will have no adverse effect on system perfcrmance.

Therefore, since the new isolation boundaries will continue to meet all design requirements, incorporation of these valves into the TS will not adversely affect safety.

Information Supporting a Finding of No Significant Hazy ds Consideration We have concluded that the proposed cb nges to the LGS Unit 2 TS wh %

reduce the number of isolation boundaries % changing the isclation boundary -

specified in TS from the HCU to the newly installed isolation valves on each common CRD header, do not constitute a significant hazards consideration. In support of this determination, an evaluation of each of the three (3) standards set forth in 10CFR50.92 is'provided below.

1. -The proposed TS changes do not involve a significant increase in the probability or consequences of an accTdent previously evaiuated.

The piaing to be included within the new isolation boundary complies with tie same standards and specifications as the original boundary.

The number.of_ active components making up the boundary will be reduced from approximately 1300 to four (4). Therefore, there will be no increase in the probability that the isolation boundary will be -

breached.

The current CRD isolation boundary includes the insert and withdraw lines,'the scram discharge volume and the HCus. The relocation of the boundary will add some of the supply header piping but will not affect the existing equipment. The added piping is small diameter (i.e., 2 inch or less) comparable to the previously analyzed scram discharge drain line. The consequences of a pipe failure inside the isolation boundary remain within the envelope analyzed in NUREG-0803.

Therefore, the proposed changes do not involve an increase in the probability or consequences of an accident previously eveluated.

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L 2 .' ,The proposed TS changes do not create the possibility of a new or ~

_ different kind of accident fro'm any accident previously evaluated.

The proposed TS changes are intended to take credit for the newly installed isolation valves on the CR0 common headers. These valves

-and associated piping are designed and installed in compliance with all applicable criteria. In addition, they will meet all performance requirements currently existing for the aoproximately 1300 HCU isolation boundaries. In effect, the only change will be to reduce the testable penetrations-from 1300 to four (4). The proposed TS changes substitute one isolation boundary for another and therefore cannot create a new or different kind of accident from any previously evaluated.

3.- The proposed TS changes do not involve a significant reduction in a margin of safety.

-.As discussed in itemsL1 and 2 above, the newly installed valves and associated aiping meet all applicable design requirements. In addition, tle consequences of a pipe failure inside the isolation boundary remain within the envelope analyzed in NUREG-0803. The valves-will be tested to ensure compliance with existing performance requirements for isolation boundaries. Further, the performance of l .the CRD system with the added pressure-drop is well within the system capability for normal-operation, and control rod scram performance is j unaffected. Therefore, the proposed changes do not irwolve a reduction in a margin of_ safety.

Inform 3tiion Supporting an Environa. ental Assessment An environmental 1 assessment is not required for the changes proposed by this Changa Request because the requested changes conform to the criteria for

" actions eligible for categorical-exclusion," as specified in 10CFR51.22(c)(9).

The requested changes willshave-no impact on the environment. The proposed changes do not; involve a.significant hazards consideration as discus ad in the

preceding section. :The proposed changes do not involve la significant change _in the types or significant increaselin the amounts of any effluents that may be

-released offsite. In addition,.the proposed changes do not involve a 1significant. increase in individual or cumulative occupational radiation exposure.

Conclusion The. Plant: Operations Review Committee and the Nuclear Review Board have reviewed these proposed changes to the TS and have concluded that they do not

" involve an unreviewed safety question, or a significant hazards consideration,

-and will not endanger the health and safety of the public.

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