ML20006B532

Forwards Info Re LLRT of Isolation Valves in non-LOCA Direction,Per Licensee Commitment to Provide Updated Info

ML20006B532
Person / Time
Site:	Brunswick
Issue date:	01/25/1990
From:	Cutter A CAROLINA POWER & LIGHT CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NLS-90-013, NLS-90-13, NUDOCS 9002050034
Download: ML20006B532 (9)

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- cn.-=c-P.O. Box 1551

• Ralegti, N.C. 27602

'JAN 2 51990 A. B CUTTER SERIAL: NLS 90 013-Wce President 10CFR50, Appendix J Nuc6 ear Services Department

. United States Nuclear Regulatory Commission ATTENTION: Document Control Desk Washington, DC 20555 BRUNSWICK STEAM ELECTRIC PLANT, UNIT NOS. 1 AND 2 i

. DOCKET NOS. 50-325 6 50-324/ LICENSE NOS. DPR 71 & DPR-62 LLRT OF ISOLATION VALVES IN THE NON LOCA- DIRECTION Centlemen:

On October 17, 1985, the NRC issued Inspection Report 85-31 for the Brunswick Steam Electric Plant Unit Nos.1 and 2 regarding inspections performed on September 9.- 13 and September 23 26, 1985. During the course of these inspections, the Appendix J Type C test procedures were reviewed to determine which valves were tested in the reverse (non LOCA) direction. As a result of j ~, the inspection, Carolina Power & Light Company committed to submic a report to the NRR which would include justification and evaluation of testing isolation valves in the reverse direction. This report was submitted on August 13,

'1987.

l The NRC Staff is currently reviewing this report and requested the Company to-update the information to reflect the current plant testing configuration. In a letter dated November 16, 1989, CP&L committed to provide an updated report by January 26,-1990. The revised report, superseding our submittal of August 13. 1987, is attached.

Please-refer any questions regarding this submittal to Mr. M. R. Oates at (919) 546 6063.

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l Yours very truI ,

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cc: Mr. S. D. Ebneter Mr. W. H. Ruland Mr. E. G. Tourigny  !

.0 9002050034 900125 PDR ADOCK 05000324 P F L L g.

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1DCAL LEAK RATE TESTING OF VALVES IN THE NON-LOCA DIRECTION The requirements for local leak rate testing of containment isolation valves are located in 10 CFR 50, Appendix J. Appendix J states, in part, "the pressure shall be applied in the same direction as that when the valve would be required to perform it's safety function, unless it can be determined that the results from the tests for a pressure applied in a_different direction will provide equivalent or more conservative results." The Brunswick plant was designed prior to the current Appendix J criteria, thus, manual test block valves and test connections are not always available for testing with pressure-applied from the containment direction. This report evaluates local leak rate testing at Brunswick and justifies the local leak rate testing of certain valves with pressure applied from the non LOCA direction.

There are a total of 27 valves on Brunswick 1 and 24 valves on Brunswick-2 that are local leak rate tested for 10 CFR 50, Appendix J requirements with test pressure applied to the valve in a direction which is not the same as would be exerted during post-LOCA containment pressurization. The following table summarizes the types of-valves and testing conditions involved. The table in Attachment I summarizes the sizes and locations of the valves being reverse tested at Brunswick.

Valve Type Brunswick-1 Brunswick-2 i

Gate Valve 9 8 )

i Globe Valve 8 8 (pressure applied below the seat)

Globe Valve 2 0 (pressure applied above the seat)

' Solenoid Valves 2 2 Butterfly Valves _6 _f l Total 27 24 l

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Cate Valves The following table specifies the gate valves which are currently being tested by reverse direction LLRT at Brunswick. In this table, and subsequent tables, i

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valves whichiapply'only to one unit are' indicated with a unit designation.

E Valves with no unit designation are common to both units.  ;

c-B21-F016* (Unit 1).

E51 F007* (Unit 1)-

B32-V22 _E51-F066 (Unit-2) l E11-F009 G16 F003  !

E11-F022* G16-F019 E41 F002 G31-F001* (Unit 1)

E41-F079 (Unit 2)

These valves will be tested in the LOCA direction after modifications to p be performed during Reload 7 for Brunswick 1 and Reload 9 for l' Brunswick 2.

These valves' incorporate a wedge-shaped disk which seats on both seating surfaces simultaneously. For motor-operated valves, the valve actuator exerts a closing-thrust which is many times greater than that placed on the valve as-a result of _ the containment test pressure of 49: psig. The following table summarizes the closing thrust to test pressure ratios:

Valve Eing Closinz Thrust Test Pressure Ratio (1bs) (1bs) y B21-F016 3" 4691 332 14.1

B32-V22 3/4" 1246 26 47.9 E11-F009 20"- 41760 10797.3 3.87 .

E41-F002 10" 27266 -3204.4 8.5 E41 F079 2" 1605 164.6 9.75 '

E51-F007 3" 4626 332 13.9 .

E51-F066 2" 1605 164.6 9.75 G31 F001 -6" 14079 1356.9 10.4 e ,

As shown above, the minimum ratio of stem closing thrust versus disk force applied by the test pressure is 3.87. Thus, due to the wedge design of the gate' disk and the fact that the actuator exerts a force several times greater  ;

.than that exerted on the disk by test pressure, two seating surfaces are '

maintained regardless of'the direction in which the test pressure is applied.

For valves C16 F003.and G16-F019, a piping section was located vnich can.be- ,

removed for installation'of a test flange to allow testing from the LOCA  !

direction. Action items have been established to revise the local leak rate testing procedure to implement testing in this new manner during the 1990 +

Reload 7 outage on Brunswick-1 and the 1991 Reload 9 outage on Brunswick-2.

Also, valves B21 F016, E51-F007, and G31-F001 will be replaced on Brunswick-1 in_the upcoming 1990 Reload 7 outage. In conjunction with the valve +

replacement, test connections are being added to allow testing from the l containment direction. These modifications were completed for Brunswick-2 during the current Reload 8 outage. Test connections will also be added to valve E41-F002 during the 1990 Reload 7 outage on Brunswick-1 and the 1991 Reload 9 outage on Brunswick-2.

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Valve E11-F022 and t' associated piping is no longer used. The-valve has-been de energized and a under clearance in the closed position. The' pipe still penetrates the etntainment wall (E11-F022 is in the drywell), but the pipe has been disconnected from the reactor coolant pressure boundary.and has a blind flange downstream of the valve. The valve must still be tested because it contains Baskets or packing which are potential leak paths into the pipe. Since the system is never used and the valve is not stroked, leakage through this path is not likely. The system will' also be subject to Integrated Leak Rate Testing. Thus, the likelihood for leakage is.small and present testing should be adequate to. preclude future leakage. Also, a recommendation is currently being reviewed to remove:the valve and associated -

piping and cap the drywell penetration.

The only remaining leakage path to be addressed for the gate valves is through the packing' Normally, the containment side disk of the gate should prevent the packing from being exposed to accident pressure. Under post-accident conditions, the valve packing will only be challenged in the unlikely event that the disk closest to containment is not leak tight and the disk furthest from containment is leak tight. The following three categories address this potential.

Category A: ' Valves located inside containment.

B21-F016 (Unit 1) E41-F002 E11.F009 E51-F007 (Unit 1)

E11-F022 C31 F001 (Unit 1)

Any leakage from the system to atmosphere through the packing would remain linside containment. Leakage from containment into the system through the packing would not bypass the valve since the only case in which the packing is not tested during LIRT is when the outboard seating surface is' leak tight.

Category B: Recirculation Pump Seal Valve -

B32-V22 This valve is located on a 3/4 inch line which connects'to the reactor recirculation pump seals and is pressurized in excess'of 1000 psig while at power. The stem is only 3/8 inch and, thus, a severe packing leak would create only a very small leakage path, The valve is located on the 20 foot  ;

elevation which is the entrance level to the building. As such, packing leakage would readily be evident to operations personnel during shift plant  !

inspections.  ;

Category C: HPCI/RCIC Turbine Exhaust Vacuum Breaker Lines E41-F079 (Unit 2) E51-F066 (Unit 2)

These are the first valves off the torus. No platform exists to access these penetrations inside the torus for testing. They are normally open and )

isolated from steam flow from the turbines by double check valves. Thus, they  ;

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are normally exposed only to torus atmosphere and typically only stroked for quarterly _ testing. As such, packing wear should be minimal. In addition, the~

valves have historically exhibited satisfactory results during integrated leak.

rate testing, i

f globe Valves'(tested from beneath the seat) i The following globe valves are currently being tested by reverse direction LLRT and with test pressure applied beneath the seat:

B21-F022A B32 F019 B21.F022B- B32 V30 B21-F022C E11 F027A B21 F022D E11-F027B .

Testing these globe valves from the non LDCA direction is more conservative L because the test pressure attempts to lift the disc from its seat rather than compress it into the seat. .Therefore, leakage measured during testing is likely of greater magnitude than that which would occur during a LOCA.

However, testing from beneath the seat isolates the packing from test pressure. Further justification for any packing leakage is provided below.

The following globe valves are inside the drywell: 1 B21-F022A B21-F022D B21-F022B B32-F019 B21-F022C Any packing leakage would remain inside the primary containment. Therefore, the LLRT, as presently performed, verifies the integrity of the possible.

containment leak paths for these valves.

Two valves are located on the torus spray header:

E11-F027A E11-F027B The spray header contains multiple nozzles, as such, these valves cannot be tested in the LOCa direction. The packing has exhibited satisfactory results during integrated leak rate testing. The valves are only stroked for testing and the packing is isolated from the RHR system by the dink when the RHR system is used. Thus, severe packing failure is unlikely.

The remaining globe valve is a recirculation pump seal valve located on the seal injection line to the recirculation pump:

B32-V30 The valve is located on a 3/4 inch line which connect to the reactor recirculation pump seals and is pressurized in excess of 1000 psig while at l

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3 power. The stem is only 5/8 inch and, thus, a severe. packing leak would create only a very small leakage path. The valve is located on the 20 foot elevation which is the entrance level to the building. . As such, packing _

leakage would readily be evident to operations personnel during shift plant inspections.

I Globe Valves (tested from above the seat)

E41-F079 (Unit 1) E51-F066 (Unit 1)

These globe valves are pressurized from above the disk during the local leak rate test. Although test pressure does not tend to unscat the disc, the test does verify the disc to seat seal and the valve packing. As such, testing in this manner is preferred for this application. These valves are on the HPCI/RCIC turbine exhaust vacuum breaker lines. The configuration of the vacuum breaker lines is such that they tie into the turbine exhaust lines between the torus penetration and the containment isolation valves for the exhaust lines and for RHR drain lines. The exhaust lines and RHR drain lines' containment isolation valves are also leak tested with water per ASME l Section XI criteria. Thus, leakage past the referenced valve seats will be bound by the second valve on the vacuum breaker line as well as the containment isolation valves on the turbine exhaust and RHR drain lines.

Therefore, at least three barriers exist for LOCA pressure at the vacrum breaker line. Hence, packing integrity of these valves is of more consequence l than leakage past the valve seat. The LLRT, as presently performed, does verify packing integrity and is the most appropriate test for this application.

l Solenoid Valves RNA-SV-5261 RNA SV-5262 These are non-interruptibic instrument air supply containment isolation valves to the drywell. Testing from the containment direction would involve using the entire instrument air system inside the drywell as a test boundary. Such a test is impractical. These valves have a one picco seal welded bonnet and thus have no leakage paths around the stems. Valve stroking occurs electrically through the bonnet. The only leakage path which exists is by the seat. However,' these solenoid valves have a plug type disk which is designed for 125 psig in the post-accident direction (i.e. under seat). Peak accident.

pressure is only 49 psig. The current LLRT verifies the leak integrity of the seat.

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1Butterf1v Valves

!s CAC-V5 CAC-V9, l CAC V6- CAC V16 d CAC-V7 CAC V17  ;

i These butterfly valves have an offset disc stem arrangement which_ places the-packing on the opposite side of the seating surface from that which LOCA pressure would! apply.. Therefore, the packing is verified by the LLRT_each  ;

refueling-outage. Since these butterfly valves are bi-directional, seal- '

leakage can be. tested from either direction.

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,n Attachment 1 Summary of Valves Tested in the Non-LOCA Direction Valve Sin Location B21-F016 3" Main Steam Line Drain Inboard Isolation Valve

'B21-F022A- 24" Inboard MSIV

.B21-F022B 24" Inboard MSIV B21-F022C 24" ' Inboard MSIV B21 F022D 24" Inboard MSIV B32-F019- 3/4" Recirculation Sample Line' Inboard Isolation Valve B32-V22 3/4" Recirculation Pump A Seal Injection Valve B32-V30 3/4" Recirculation Pump B Seal Injection Valve CAC V5- 20" Suppression Pool Nitrogen Inlet Valve CAC-V6 18" Drywell Nitrogen Inlet Valve CAC-V7 20" Inboard Suppression Pool Purge Exhaust Valve CAC-V9 18" Inboard Drywell Purge Exhaust Valve CAC-V16 20" Reactor Building to Suppression Pool Vacuum Breaker Valve CAC-V17 20" Reactor Building to Suppression Pool Vacuum Breaker Valve l i

Ell-F009 20" RHR' Shutdown Cooling Inboard Suction Throttle Valve j E11-F022 4" RHR Reactor Vessel Head Spray' Inboard Isolation  ;

Valve

l Ell-F027A 6" RHR Suppression Pool Spray Isolation Valve

-Ell-F027B 6" RHR Suppression Pool Spray Isolation Valve

- E41-F002 10" HPCI Steam Supply Inboard Isolation Valve l l

E41-F079 2" HICI Turbine Exhaust Vacuum Breaker Valve .

! E51 F007 3" RCIC Steam Supply Inboard Isolation Valve i E51-F066 2" RCIC Turbine Exhaust Vacuum Breaker Valve 1

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p* -Attachment 1-

, Summary of Valves

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Tested in the Non-LOCA Direction Valve Eigg -Location

-G16 F003 3" - Drywell Floor Drain Inboard Isolation Valve

-G16-F019 3" .Drywell Equipment Drain Inboard Isolation Valve' G31-F001 6" RWCU Inlet Inboard Isolation Valve RNA-SV 5261 2" Non Interruptible Reactor Instrument Air Isolation Valve RNA SV-5262 2" Non Interruptible Reactor Instrument Air Isolation Valve n

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