ML20029B193

Corrects 901217 Response to Generic Ltr 89-10,Suppl 3.RCIC Steam Supply Containment Isolation Valves Are Gate Valves & within Scope of Generic Ltr

ML20029B193
Person / Time
Site:	Pilgrim
Issue date:	02/26/1991
From:	Gina Davis BOSTON EDISON CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
BECO-91-022, BECO-91-22, GL-89-10, NUDOCS 9103060167
Download: ML20029B193 (5)

Text

- -. - . . - - . . -.-.. . . - - - - -..._. -. -

Qc I "

..; BOSTON EDISON Pugrim Nuclear Power Station Rocky H4 Poad . 1 Plymouth; Massachusetts 02360 l

l George W. Davis .

, i sence vce President - Nucles' Tebruary 26, 1991 BECo 91- 022 U.S. Nuclear Regulatory Commission

. Document' Control Desk i

~Hashington, D.C. 20555 l

-l License DPR-35 Docket 50-293 Amendment to Generic letter 89-10. Suoolement 3 Submittal >

He are submitting-this amendment to our response to Generic Letter 89-10, Supplement 3, due-to-a discrepancy; contained.in-our December 17, 1990 submittal. In.that submittal, we stated the RCIC steam supply containment

-isolation valves were globe valves and were thus outside the scope of Generic-Letter 89-10'-Supplement 3. He have since determined these valves are gate valves and are.within the scope of the Generic Letter. He have reviewed the RCIC valves and determined they will perform their safety function to close Lwithin the design criteria of the valve and operator.. Attachment I to our December 17, 1990. submittal has been revised and is_being resubmitted to

-reflect the analysis of the RCIC gate valves.

In accordance with our Management. Corrective Action Process, wethave

~ investigated,- determined the cause of the discrepancy, and revised the-associated documents to prevent recurrence. He conclude the HPCI,-RCIC, and RHCU-systems lare capable of-providing containment isolation in the event of_a.

line break outside containment, c I g f~~

LAtt'achment Commonwealth of Massachusetts)

< County of Plymouth _ ~)

j Then personally appeared be' ore me, George H. Davis, who.being duly sworn, did

-state that'heLis Senior Vice President - Nuclear of Boston Edison Company and

.that helis duly authorized .to-execute ~and' file the submittal contained herein-Lin the'name'and.on behalf of Boston Edison Company and that the statements in said: submittal-are true to_the best of his knowledge and belief. <

, ....,..4.o.,

My commission expires: A/J #h dal [ .k

/DATE ' NOTARY PUBLIC / f// / 5 ,

i 'ii Q Q{ n',,4 v cc: . See Page 2 p .

• . em J)  ?

9103060167 910226: .- ^

PDR ADOCK 05000293 'a c +$

ch*'/d' P -PDR '\\ q I Y. '

-- w- . .. -- - ...

l BOSTON EDISON COMPANY l U,,S, Nuclear Regulatory Comnission Page 2 l l

cc: Mr. R. Eaton, Project Manager Division of Reactor Projects - 1/II Office of Nuclear Reactor Reglilation Mail Stop: ICD 1 U. S Nuclear Regulatory Commission 1 White Flint North 11555 Rockville Pike Rockville, MD 20852 U. S. Nuclear Regulatory Commission Region I 475 Allendale Road King of Prussia, PA 19406 Senior NFC Resident Inspector Pilgrim !<ucitar Power Station ERS/ rec /5284 i

Page 1 of 3 ATTACHMENT 1. REVISl0L1 As requested by GL 89-10 Supp1r: ment 3, BECo has reviewed and evaluated HPCI valves 2301-4 and 5, RCIC valves 1301-16 and 17, and RHCU valves 1201-2 and 5 to determine if deficiencies exist relative to test results given in Information Notice (IN) 90-40.

The result of the evaluation is that each valve in question will perform its safety function to close within the design criteria of the valve and operator. The motor operated valves in question (2301-4 cnd 5, 1301-16 and 17 Ond 1201-2 and 5) are unique because they are norma)1y opei at 1001, reactor power and provide a direct path for reactor coolant outsitN the primary containment. In the event of a pipe break they must be af>le to close to mitigste flow of primary water and steam to the reactor Sullding. Other motor operated valves are normally closed at power or have chr.ck valves to prevent back flow of primary water / steam and would not be required to close under pipe break conditions at full reactor pressure.

1. HPCI Valve 2301-4 Velan (Gate) 8" SMB-2-60(AC) Torque Switch Trip 29916#

Not tested by NRC, Idaho Nuclear Engineering Laboratory (INEL) tests Since this valve was not tested by INEL, we compared similarities of PNPS valves to valves used in the NRC tests. IN 90-40 concluded that a valve friction factor of .3 did not bound the required thrust. Ten tests were done on Velan 6" and 10" valves. Nine were done with hot water or steam and the valve friction factors were .43 to .56. One test was in cold water and the valve friction factor was .63. This test was not included in the evaluation since it was not near operating conditions. The tnrust at torque switch trip obtained from static diagnostic testing of 2301-4 was evaluated at degraced voltage conditions. He concluded that the thrust is sufficient to overcome a friction factor of .6. Therefore, the valve friction factor for 2301-4 is acceptable and the valve will perform its safety function.

2. HPCI valve 2301-5, Velan (Gete) 8" SMB-1-60(DC) Torque Switch Trip - 34300#

Not tested by NRC, INEL tests An evaluation similar to 2301-4 was applied to the 2301-5 valve. The thrust is sufficient to overcome a friction factor of .7 using the thrust at torque switch trip obtained from static diagnostic testing and evaluating it at degraded voltage conditions. Therefore, the valve friction factor 's acceptable for 2301-5 and the valve will perform its safety function.

3. RCIC 1301-16 Westinghouse (Gate) 3" SMB-000-10(AC) Torque Switch Trip - 5480#

Not tested by NRC, INEL tests An evaluation similar to 2301-4 was applied to the 1301-16 valve. The thrust is sufficient to overcome a friction factor of .7 using the thrust at torque switch trip obtained from static diagnostic testing and d

evaluating it at degraded voltage conditions. Therefore, the valve friction factor is acceptable for 1301-16 and the valve will perform its safety function.

Page 2 of 3 ATTACHMENT 1. REVISBN 1

4. RCIC 1301-17 Velan (Gate) 3" SMB-000-5(DC) Torque Switch Trip - 6269#

Not tested by NRC INEL tests An evaluation similar to 2301-4 was applied to the 1301-17 valve.

thrust is sufficient to overcome a friction factor of .8 using the thrust The d' at torque switch trip obtained from static diagnostic testing and evaluating it at degraded voltage conditions. Therefore, the valve friction factor is acceptable for 1301-17 and the valve will perform its safety function.

5. RHCU 1201-2 Halworth (Gate) 6" SMB-00-15(AC) Torque Switch Trip - Not known, never tested INEL test required 12000# thrust at about 1135 psi delta pressure.

1201-2 is wired so the torque switch is by-passed for 98% of the closed stroke (Drawing E5020E7 and MR88-12-9). The by-pass is initiated by high temperature in the non-regenerative heat exchanger room, initiation of SBLC, low reactor water level, high area temperature, or high delta pressure (flow) in the RHCU system. The torque switch is not by-passed during manual operation. The high differential pressure across the valve due to blowdown momentum is not acting on the valve disc at 981 closed.

When a gate valve is closed 98%, the port is covered due to the valve disc guides and the bottom of the disc is in the valve body groove. This eliminates the blowdown force component acting on the valve disc resulting in sufficient thrust being available for final 2% closure with the torque switch in the circuit.

The INEL tests show the maximum required thrust would be about 12000# in the event there is a pipe break outside containment downstream of 1201-2.

This is within the motor operator design capability of 14000#. A " weak link analysis" for the valve / motor operator assembly is being conducted by Crane-Aloyco and will be completed by approximately 2/15/91. This is required by GL 89-10 to ensure valve components are not overstressed during operation. Crane-Aloyco has stated the valve can withstand a thrust of greater than 14000# but the exact number has not been calculated. The 1201-2 and 1201-5 valves are similar designs and the 1201-5 valve can withstand the motor operator design-thrust of 14000#.

Also the motor will not stall while the torque switch is by-passed since this value (12000#) is within the design capability of the motor operator at reduced voltage. Therefore 1201-2 will perform its safety function closing aftrer a pipe Dreak against an expected thrust of 12000#.

GL 89-10 also recommends all safety-related valves have a history to monitor deterioration. This starts with diagnostic testing and baseline signatures of each safety-rel u ed or position changeable HOV. 1201-2 shall be tested during RF0 #8. _The actual thrust at torque switch trip is not known but the limit switches have been adjusted.

I l

11,s g "'

Page 3 of 3

A.

ATTACHMENT 1. REVISION 1

6. RHCU 1201-51 Anchor / Darling (Gate)' 6" SMB-0-25(DC)LTorque Switch Trip = 15400#

INEL test: required 20000# thrust at 990 psi; delta pressure u

1.01-5-istwired 2 inltheLsame manner as 1201-2 so the torque switch.is

- by-passed for198% of-the closed stroke.

The-INEL tests show the maximum required thrust would be about 20000# i.

- the event of a pipe break outside containment downstream of 1201-5. This is withinlthe motor operator design capability of124000#. The results of the " weak link' analysis" show the weak link in closing direction to be the

-yoke leg which is capable of.57.9 kips. . Therefore, the valve and operator are acceptable-for maximum required-thrust conditions. Also the motor i will notcstal1 while:the torque switch is by-passed since this value:

- (20000#) is within the design capability of the motor operator at= reduced

Voltage. 'Therefore 1201-5 will perform its safety-related function by

closing after.a pipe break against an expected thrust of 20000#.

4 J'

vm_w .~ ,.y.-- - , . - , . y ,