ML20207S768

Forwards Safety Evaluation Permitting 870303 Relief Request from Requirements of Tech Spec 4.7.A.3 on one-time Basis in Order to Perform RHR Pump Wear Ring Replacement

ML20207S768
Person / Time
Site:	Vermont Yankee File:NorthStar Vermont Yankee icon.png
Issue date:	03/12/1987
From:	Murley T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
To:	Murphy W VERMONT YANKEE NUCLEAR POWER CORP.
Shared Package
ML20207S769	List: ML20207S768 ML20207S780
References
NUDOCS 8703200255
Download: ML20207S768 (2)

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MAR 131987 Docket No. 50-271 Vermont Yankee Nuclear Power Corporation ATTN:

Mr. Warren P. Murphy Vice President and Manager of Operations RD 5, Box 169 Ferry Road Brattleboro, Vermont 05301 Gentlemen:

Subject:

Relief from Technical Specification 4.7.A.3 This refers to your letter Serial No. FVY 87-29 dated March 3, 1987 (Enclosure 1),

in which you requested relief from the specific requirements of Technical Specifi-cation (TS) 4.7.A.3, in order to perform residual heat removal (RHR) pump wear ring replacement in a safe and expeditious manner.

This also refers to a telephone con-versation on March 12, 1987 between Mr. J. Weigand, President and Chief Executive Officer, Vermont Yankee Nuclear Power Corporation, and Mr. W. Kane, Director, Division of Reactor Projects, NRC Region I in which Mr. Weigand agreed to comply with the conditions in Attachment 1 to Enclosure 2 to this letter.

The staff has reviewed your detailed plans for inspection and maintenance of the RHR pumps.

In particular, we have reviewed the measures you will implement, and the technical bases, to assure that the intent of TS 4.7.A.3 will be met during performance of these activities.

Based on the staff's evaluation, as described in Enclosure 2, and subject to the conditions specified in the Attachment 1 to that enclosure, I will exercise enforcement discretion and permit the requested relief from TS 4.7.A.3 on a one-time basis in order to perform RHR pump wear ring replace-ment.

Sincerely, Or'IgInal signe~d lig D Mn"r. W rley Thomas E. Murley Regional Administrator

Enclosures:

As Stated 8703200255 870312 PDR ADOCK 05000271 t@I P

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Vermont Yankee Nuclear Power 2

Corporation cc w/encls:

R. W. Capstick, Licensing Engineer J. Gary Weigand, President and Chief Executive Officer J. P. Pelletier, Plant Manager Donald Hunter, Vice President Cort Richardson, Vermont Public Interest Research Group, Inc.

Gerald Tarrant, Commissioner, Department of Public Service Public Document Room (PDR)

Local Public Document Room (LPDR)

Nuclear Safety Information Center (NSIC)

NRC Resident Inspector State of New Hampshire State of Vermont bcc w/encls:

H. Denton, NRR R. Bernero, NRR D. Muller, NRR V. Rooney, NRR G. Rivenbark, NRR H. Abelson, NRR J. Taylor, IE J. Allan, RI W. Kane, RI S. Collins, RI E. Wenzinger, RI T. Elsasser, RI W. Raymond, RI D. Haverkamp, RI W. Johnston, RI L. Bettenhausen, RI J. Durr, RI J. Johnson, RI T. Martin, RI Region I Docket Room (with concurrences)

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E m 0SURE 1 VERMONT YANKEE NUCLEAR POWER CORPORATION FVY 87-29 RD 5. Box 169. Ferry Road. Brattleboro, VT c5301

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ENGINEERING OFFICE 1671 WORCESTER ROAD

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s-FR AMINGHAM. MASS ACHUSETTS 01701 TELEp oNE to 472 soc March 3, 1987 U.S. Nuclear Regulatory Commission Regional Administrator Region I 631 Park Avenue King of Prussia, PA 19406

References:

(1) License No. DPR-28 (Docket No. 50-271)

(2) letter, VYNDC to USNRC, FVY 86-78, Changes to the Technical Specifications for the 1986/1987 Operating Cycle Inspection / Repair of the RHR Pump Impeller Wear Rings, dated 8/28/86 (3) Letter, VYNPC to USNRC, FVY 84-76, " Vermont Yankee Primary Containment Leak Rate Testing Program", dated 6/26/84 (4) Letter, VYNPC to USNRC, FVY 86-97, Supplemental Response to NRC Request for Additional Information - Appendix J Technical Specifications, dated 10/10/86 (5)

V.Y. Technical Specification 4.7.A.3 (6) Letter, USNRC to VYNPC, NVY 86-237, dated 12/4/86 (7) Discussion, VY Resident Inspector with VY Staff, 2/27/87

Subject:

Request For Relief From Technical Specification 4.7.A.3 For Performing RHR Wear Ring Replacement

Dear Sirs:

As a result of our review during the past month and per Reference 7, Vermont Yankee requests relief from Technical Specification 4.7.A.3 in order to perform the RHR Wear Ring Replacement in an expeditious and safe manner.

T.S.

4.7.A.3 states:

" Prior to violating the integrity of a system outside the Primary Containment which is connected to any valve listed in Table 4.7.28, the isolation valves bounding the opening shall have Type C tests performed.

If the opening cannot be isolated from the containment by two isolation valves which meet the acceptance criteria of Appendix J (10 CFR Part 50), a blank flange shall be installed on the opening".

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'.U.S. Nuclear Regulatory Commission March 3, 1987 Page 2 VERMONT YANKEE NL* CLEAR POWEH CORPORATION In order to initiate and complete the RHR Wear Ring Replacement, Vermont Yankee must utilize T.S. 4.7.A.3.

Isolation valves RHR 17 and RHR 18 which are used for the RHR Shutdown Cooling function are listed in Technical Specification Table 4.7.2b and would be used to " bound the opening" that will result when the RHR pump is disassembled.

Although not mentioned in Table 4.7.2b, RHR 13 and RHR 15 valves also isolate the pump from the primary system (see FSAR Figure 4.8-2).

Although it is possible to leak test the RHR 17 valve, the results may not be conclusive since testing of the RHR 17 valve for leakage may be affected by the RHR-18 valve water leakage. RHR-18 has approximately a 1000 psig differential pressure during operating conditions versus a 44 psig differential pressure during acci-dent conditions.

The RHR-18 valve water leak rate under normal conditions could be acceptably higher than the Appendix J air leak rate under accident con-ditions.

It should be noted, however, that on-line relief valves and pressure switch indications located downstream of RHR18 and RHR17, do not and have not indicated leakage past these valves. RHR 18 valve can not be tested under Appendix J conditions during operation.

Additionally, air could be introduced into the system which could set up an air hamer potential.

The RHR would remain " solid" if no leak testing is attempted.

The intent of T.S. 4.7.A.3, however, can_be met when;

1) Valve RHR 15 is tagged and locked shut (this can be considered equivalent to a blind flange).

2) Tail pipe leakage and pressure monitoring (downstream of the RHR 17 and 18 valves) are monitored (this can be considered equiva-lent protection to leak testing).

During normal operation, the RHR system forms a seismically qualified loop which penetrates the containment and thus leakage by the penetration isolation valves, if any, would not have a clear path to the atmosphere.

During RHR impeller replacement the RHR 15 valve will be closed and will help provide a wa.ter seal on valves RHR 17 and 18 which will also remain closed.

This will provide a similar water seal as is available during normal operation. During normal operations (normal reactor pressure), annunciation / instrumentation exists which checks leakage past penetration X-12 isolation valves (RHR 17 and 18) by monitoring downstream pressure. The pressure setpoint is 100 psig which is monitored by PS-ll8. Additionally, there is a safety relief valve (SR-40) which is downstream of penetration X-12 that is set at 150 psig.

Therefore, if penetration X-12 isolation valves should leak during operation, these components would indicate a problem by annunciation or by tail pipe leakage.

Thus, the boundary intpority can be checked which would identify leaks and initiate repairs. As described above even though VY will not formally leak test these valves, sufficient means are,available to give positive assurance that the penetration isolation valves, RHR 17 and 18, will perform their required function.

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U.S. Nuclear Regulatory Comission March 3, 1987 Page 3 VERMONT YANKEE Nt' CLEAR POWER CORPOR ATION It should also be noted that primary contuiment is maintained by water seal for the RHR-13A, B, C, D valves, which will also be isolated (1 valve per pump isolation) during this work effort.

To ensure equivalent primary containment protection, the following have been considered; Administrative Controls VY will white tag the appropriate RHR 13 and 15 valves shut in accordance with existing administrative procedures and will open the motor operator breaker.

This will ensure that the valve is maintained closed and is electri-cally disarmed.

Leakage Potential In order to perform the RHR Wear Ring Replacement, the leakage rate will need to be minimized so that the required internal inspections / work can be per-formed. The RHR pumps have drain lines which can drain approximately 5 gpm for anticipated condition.

If the design basis LOCA occurred during this repair period, it is evaluated that:

a) the. leakage rate would significantly decrease in the RHR shutdown cooling line.

(i.e. valves RHR 18, 17, 15) because differential pressure would decrease from normal operating pressure of approximately 1000 psig to 44 psig.

b) the leakage rate from the torus suction line (i.e. valve RHR 13) would approximately triple (based on flow rate being directly proportional to the square root of the pressure differential).

It should also be noted that the anticipated leakage is negligible to the amount of water added to the vessel and torus by core spray and the three remaining RHR pumps. This leakage will be controlled (i.e., is directed to the sump / pump / floor drain /radwaste). The water that could exit the open pump would be subcooled and therefore any potential contaminated source in the water would I

remain as particulate (or dissolved) and would have a low potential to become airborne. The inert gases have low solubility and therefore would not be released in significant quantities.

Therefore, under design basis LOCA con-ditions, coolant leakage and potential airborne activity would be minimized.

Safety Considerations Vermont Yankee judges that the measures described above, which will allow us to meet the intent of Appendix J, Type C testing are sufficient to allow performance of RHR Pump Wear Ring Inspection / Replacement. Vermont Yankee has received the SER (Reference 6) and special technical specification

U.S. Nuclear Regulatori Comission March 3, 1987 Page 4 VERMONT YANKEE NL' CLEAR POWEH CORPORATION from the NRC related to our planned RHR Impeller Replacement. VY has requested removal of Technical Specification 4.7.A.3 (see Reference 4) tecause; 1) the specification cannot be effectively applied; '

2) it does not appear in Standard Technical Specifications, and

3) for each penetration either a testing plan was specified or an eva-luation performed negating the need for Appendix J testing.

l Additionally, for the present configuration, the closing and de-energization of the motor breaker of the RHR 15 and RHR 13 valves effectively meet the intent of Technical Specification 4.7.A.3.

Based on the above, Vermont Yankee requests that relief from Technical Specification 4.7.A.3 be granted.

Very truly yours, VERMONT YANKEE NUCLEAR POWER CORPORATION W

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urphyl*h Warren P.

l Vice President and Manager of Operations l

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