ML19256B171

Forwards Addl Info Re Local Leak Rate Testing Requested 790110 by Phone.Info Provides Basis for Local Leak Rate Testing of Some Containment Isolation Valves W/Water as Test Medium.Info to Be Incorporated Into FSAR

ML19256B171
Person / Time
Site:	Sequoyah
Issue date:	01/18/1979
From:	Gilleland J TENNESSEE VALLEY AUTHORITY
To:	Varga S Office of Nuclear Reactor Regulation
References
NUDOCS 7901240198
Download: ML19256B171 (11)

Text

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. 4 TENNESSEE VALLEY AUTHORITY CHATTANOOGA. TENNESSEE 37401 500C Chestnut Street Tower II JAN 181979 Director of Nuclear Reactor Regulation Attention: Mr. S. A. Varga, Chief Light Water Reac' ors Branch No. 4 Division of Project bbnagement U.S. Nuclear Regulatory Commission Washington, DC 20555

Dear Mr. Varga:

In the Matter of the Application of ) Docket Nos. 50-327 Tennessee Valley Authority ) 50-328 Enclosed is the additional information concerning local leak rate testing at the Sequoyah '..uclear Plant requested by the Nuclear Regulatory Commission (NRC) Containment Systems Branch reviewer i.

a telephone converse'. ion on January 10, 1979. The material specifies the basis for local leak rate testing of some containment isolation valves with water as the test medium. Amendment 60 to the Sequoyah Nuclear Plant Final Safety Analysis Report will incorporate the enclosed material.

Very truly yours, o,t J. E. Gillelan'd Assistant Manager of Power Enclosure (10) 790124 0/9?

An Equal Opportunity Employer

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• LOCAL LEAK RATE TESTIUG OF CONTAINMENT 9 8 ISOLATICN VALVES l

b Appendix J of 10CFR50, which specifies the integrated and local leakage rate testing requirements for containments, was published long af ter the construction of Sequoyah began and Sequoyah has not been required to conform to those requirements. The Seguoyah FSAR outlines TVA's present leak rate testing program for containment isolation valves. The test program permits the use of air er water as the test medium for local leak rate testing of isciation valves. Late this summer there were indications that the NRC may no longer accept water as a test medium for plants the vintage of Sequoyah. In october of this year TVA contacted the Eegulatory Staff and requested clarification on this issue due to the potential impact on the Sequoyah startup date. The Staff verbally responded in telephone discussions that the use of air is required on all valves as specified in 10CFR50, Appendix J, except for cases of obvious hardship or justification i

which would show that the potential for release of containment atmosphere is small.

TVA has reviewed the piping layouts at Sequoyah to determine the

, specific plant design features and such modifications to the plant as would be required to permit local valve testing in conformance with Appendix J. The local valve test program considers 75 penetrations. Forty-four penetrations were scheduled to be tested with water instead of air. The remaining 31 penetrations would be tested with air as required by Appendix J. We determined from the system-by-system review of the 4 4 water test penetrations that 17 penetrations could and will be tested as required by Appendix J prior to initial plant operation. The remaining 27 water test penetrations were found to require hardware modifications which cannot be inplemented without delaying the fuel load date of April 1979.

TVA therefore requests that leak rate testing with water of the isolation valves associated with these 27 penetrations he permitted for plant operation during the first fuel cycle. TVA will, during the first refueling outage, modify the plant so that all future local leak rate testing will b.. done in full compliance with Appendix J.

The problem with any modilications at this time is that plant preoperational testing (such as hot functional testing scheduled from January, 1979 through February) requires the proper function of many systems simultaneously to support any particular test.

Some tests (such as the~ Type A containment leak test scheduled in February) preclude physical access to areas required to perform modifications. There are few time periodo left between now and scheduled fuel loading when we have both physical access to certain equipment and freedom from its functional tie to cther testing. These periods are already scheduled for intense testing .

activity that can only be done during such pericds. Our every effort at this time is to direct our construction and testing I program towards minimizing any further delays in the critical path schedule for fuel loading and plant operation. To alter the

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lor mo Ifications at this time is certain to cause additicnal delay.

The attached table lists each of the systems and penetrations for which an exemption is requested. A brief discussion is provided f~' f or each system giving a basis for permitting the one-time-only water test. Factors discussed are procurement delays, system status, and design features which, in addition to the containment isolation provisions, would limit the release of radioactive material from the containment. TVA believes that plant and public safety are nct compromised by permitting these few one-time water tests.

A cne time exemption from the draining requirements of Appendix J for the Type A test is also requested for the penetrations provided in the attached table. These lines will he vented in accordance with the Type A procedures in Appendix J, however, the modificaticns required to perform the Type C test with air'are also required in order to properly drain these lines for the Type A test.

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s Fenetration Modifications Easis for a Wal.er: Teut System Number Recuired for First Fuel Cycle Ice Condenser X-47A In-Line Block Ice loading is presently underway.

Valve & Drain Modifications would require the syster valve to be removed from service which would delay ice loading. Ice loading is a X-47B In-Line Block critical path item and any delays are Valve & Drain translated directly to the fuel load valve date. Additionally, the in-line blcck X-114 Drain Valve valves cannot be procured prior to X-115 Drain valvc start-up of the plant.

UHI X-110 2 Blind Preoperational testing is presently Flanges S underway on this system. The system

'agg 2 Vent valves would have to be removed from service ggg=,;'= ) to make modifications. This line has,

--d in addition to the containment iso-laticn valves, a manual normally closed

$35d Class E glche valve located outside containment in each branch of the line.

6 9- Any leakage from this system would be 2359 treated by the Auxiliary Building Gas Treatment System (AEGTS) prior to bd cd release to the outdoors. The principal tests that could be delayed by requiring N?2d modification to this system are:

553D 1) Containment Integrated Leak Bate Test b 2) Hot Functional Tests Domineralized X-77 2 Drain Valves S stem tests (non-critical) are Water scheduled for January 1979. The required modifications would delay putting this system in Service.

Portions of this system are located in the Auxiliary Building where any leakage across the isolation valves

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Penetration hodifications Easis for a Wal.or Tunt System Nur.ber Reauired for First Fuel Cvele would he treated by the AEGTS. The principal tests that could he delayed by by requiring modification to this system are:

1) Containment Integrated Leak Rate Test

2) Hot Functional Tests Component X-29 Drain Valve Freoperational testing has been com-Cooling pleted for this system. The system Water X-52 Drain valve would haye to be removed from service to make modifications. This would TEN X-35 Drain valve & delay the performance of other pre-QZZ3 Cross Connect operational tests and thereby delay

@==9- fuel loading. The Component Cooling gggg X-53 Drain valve & Kater System is a Class C, seismic Cross Connect Category I closed loop piping system q g outside cf containment. Any leakage 51E0 across the isolaticn valves would be contained in the system piping and gg g . not released to the atmosphere. The principal tests that could be delayed by pand requiring modification to this system are:

g 1) Containment Integrated Leak Bate Test b 2) Hot Functional Tests

3) CVCS Tests

4) Onsite Power Distribution Load Tests

5) ECP Tests CVCS X-15 In-Line Block Preoperaticnal testing is presently Valve C 2 underway on this system: The system Drain valves would have to to removed from service to make modifications. Additionally, X-44 Drain Valve the CVCS is a Class E, seismic Category I closed system outside of

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penetration Svstem Eumber Rodifications Recuired Easis for a Natur Tent for First Fuel Cycle the primary containment. Any leakage across the isolation valves would he trapped in the system piping and not released to the atmosphere. The closed portions of this system are located in areas of the auxiliary building which are served by the ABGTS. The in-line block valve cannot he procured prior to fuel loading. The principal tests that could he delayed by requiring modification to this system are:

1) Containment Integrated Leak Bate Test

2) Hot Functional Tests

3) Oncite Power Distribution Load Tests

4) Full Flow Tests A/C Chilled X-64 Drain Valve System testing (non-critical) is Water presently scheduled for late January X-65 Crain Valve 1979. Mcdification would delay testing and putting the system in X-66 Drain Valve service. This is a closed system F75d

(< 9 X-67 Drain Valve incide ccntainment located in the instrument room. The piping is f~3 ANSI E31.1 and seismic category I, gggg therefore it is unlikely that a release of radicactivity wculd occur g following a LOCA due to this system.

$350 The principal tests that could he delayed by requiring modification to this syster b5IO are:

1) Containment Integrated Leak Fate Test pggg 2) Hot Functional Tests p .

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Fenetration Modifications Easis for a Gal.er Tent Svstem  ?;umbe r Recuired for First Fuel Cvcle Floors & Equip- X-41 Drain Valve The preoperational test for this ment Drains system is presently underway. Modifica-tions would delay putting the system in service. This system is located in the Auxiliary Euilding and any leakage across the isolation valves would be treated by the AEGTS. The principal tests that could be delayed by requiring modification to this system are:

1) Containment Integrated Leak Rate Test

2) Eat Functional Tests Primary Water X-42 Drain Valve Prooperational testing on this syster is scheduled for December 1978.

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• This test is a prerequisite to other CSEEd tests required prior to startup.

6__3 Modification of this system at this

$399 time wculd delay the performance of this test and therefore delay fuel

(< >) loading. The principal tests that cculd gggg he delayed by requiring modificaticn to this system are:

[]2) 1) Centainment Integrated Leak Fate Test

2) Hot Functional Tests

3) CVCS Tests gj5D 4) Eoron Recycle Test y 5) Boric Acid Test

~ Fuel Poc1 Cooling X-82 In-Line Block Freoperational testing on tb.is Valve system has been ccmpleted. The in-line block valve cannot he procured pricr to fuel loading.

Fenetration Modifications Easis for a Watm; Test Svste.? Number Roauired for First Fuel Cyclo ERC% Supply X-56 Drain Valve Freoperational testing on this system is underway at the present time.

X-58 Dr L1 valve Modifications would require that the system he removed from service. A X-60 Drain Valve functional ERCW system is a pre-requisite for the performance cf many X-62 Drain valve remaining preoperational and system tests. Fuel loading will incur a X-68 Crain Valve minimum of a day to day delay for

' time the ERCW is out of service.

X-69 Drain Valve The ERCU is a seismic Category I Class C system. There is a X-74 Drain Valve sufficient elevation difference in the piping outside of containment tc X-75 Drain Valve maintain a 10 psig water leg seal in the supply lines after an accident.

This water leg seal would limit the release of radioactive material which leaks past the isolation valves to a very small amcunt. The ERCh "Tgg discharge lines are scaled with a y g seal system which meets the g g requirements of 10CFR50, Appendix J.

The principal tests that could he bEEO delayed by requiring mcdificaticn to this system are:

6=rb 1) Containment Integrated Leak Bate Test 555d

2) Hot Functional Tests

3) HVAC Tests fh 74gp

4) CVCS Tests

5) RI!R Tests

6) Containment Spray Tests 5533 7) SIS Tests b 8) Onsite Power Distributicn Load Tests S) Ccmponent Cooling Water Tests 10)Ccntrcl Eay HVAC Tests

WATER .EAKAGE TO AIR LEAKAGE COtiVERSION In order to support our request for a o.'c time water test on f certain fluid lines a t the Sequoyah Iluclear Plant, TVA is supplying wa ter to air leakage conversion data. The data was developed for use at Unit 2 of the Browns Ferry Plant.

As part of our evaluation of converting isolation valve water leakage to gas equivalent, TVA empirically measured both air and water leakage through several typical valves. The purpoco of this program was twofold. The first purpose was to reproduce the data presented in a technical report by Maine Yankee Atomic vouer Ccrpany entitled " Water Leakage to Air Leakage Correlation." The sec nd purpose of the program was to extend the Maine Yankee tests to cover a larger range of leakagcc and valve types. The range of leakages was to cover those typically oncountered in a type C test program.

A comparison of the water and air leakage for those valves tested in the TVA program is depicted in Figure 1. Data from Maine Yankee is included for reference. There is reasonable agreement betwoon the Maine Yankee and the data collected by TVA for the range of water leakage considered in the Maine Yankee report.

Figure 2 depicts the conversion curve presented in the 14aine Yankee report and that obtained in these tests. The larger degree of scatter from the fit line for the 1/A tests is attributable in part to the larger range of valve sizes tested.

The TVA curve presented in Figure 2 uns used at Browns Ferry.

This curve was based on tests conducted at 50 psig. Tne Sequoyah Type C test is performed at 12 psig. Therefore the curve should be corrected for the pressure difference. We intend to use the TVA curve (Figure 2) modified by multiplying the air leakage values by the square root of the pressure ratio between Sequoyah and Brouns Ferry (i.e., $/i2/5 0' ) at Sequoyah. Appendix J uses this method of ratioing pressure to evaluate the leak rate for the' Type A reduced pressure test. This water to air conversion method uould be used only for the preoperational test.

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