ML18153A329

Application for Amends to Licenses DPR-32 & DPR-37,modifying Testing Requirements for Reactor Trip Bypass Breaker

ML18153A329
Person / Time
Site:	Surry
Issue date:	09/24/1998
From:	Ohanlon J VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML18153A330	List: ML18153A329 ML18153A331
References
98-564, NUDOCS 9809280265
Download: ML18153A329 (9)

Text

VIRGINIA ELECTRIC AND PowER COMPANY RICHMOND, VIRGINIA 23261 September 24, 1998 U.S. Nuclear Regulatory Commission Serial No.98-564 Attention: Document Control Desk NL&OS/GDM RO Washington, D.C. 20555 Docket Nos. 50-280 50-281 License Nos. DPR-32 DPR-37 Gentlemen:

VIRGINIA ELECTRIC AND POWER COMPANY SURRY POWER STATION UNITS 1 AND 2 PROPOSED TECHNICAL SPECIFICATION CHANGE REACTOR TRIP BYPASS BREAKER SEQUENCE CHANGE Pursuant to 10 CFR 50.90, Virginia Electric and Power Company requests amendments, in the form of changes to the Technical Specifications to Facility Operating License Numbers DPR-32 and DPR-37 for Surry Power Station Units 1 and 2, respectively. The proposed changes will modify the testing requirements for the reactor trip bypass breaker. A discussion of the proposed Technical Specifications change is provided in Attachment 1.

The proposed Technical Specifications change has been reviewed and approved by the Station Nuclear Safety and Operating Committee and the. Management Safety Review Committee. It has been determined that the proposed Technical Specifications change does not involve an unreviewed safety question as defined in 10 CFR 50.59 or a significant hazards consideration as defined in 10 CFR 50.92. The proposed Technical Specifications change is provided in Attachment 2. The basis for our determination that the change does not involve a significant hazards consideration is provided in Attachment 3.

If you have any questions or require additional information, please contact us.

Very truly yours,

~?.~

James P. O'Hanlon Senior Vice President - Nuclea*r

( 9809280265 980924

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Attachments

• e

1. Discussion of Changes

2. Proposed Technical Specifications Change

3. Significant Hazards Consideration Determination Commitments made in this letter:

1. The commitments made in this letter are as indicated in the proposed Technical Specifications.

cc: U.S. Nuclear Regulatory Commission Region II Atlanta Federal Center 61 Forsyth Street, SW Suite 23T85 Atlanta, Georgia 30303 Mr. R. A. Musser NRC Senior Resident Inspector Surry Power Station Commissioner Department of Radiological Health Room 104A 1500 East Main Street Richmond, VA 23219

COMMONWEALTH OF VIRGINIA )

)

COUNTY OF HENRICO )

The foregoing document was acknowledged before me, in and for the County and Commonwealth aforesaid, today by J. P. O'Hanlon, who is Senior Vice President - Nuclear, of Virginia Electric and Power Company. He has affirmed before me that he is duly authorized to execute and file the foregoing document in behalf of that Company, and that the statements in the document are true to the best of his knowledge and belief.

Acknowledged before me thiso/~J!Jday of lp.Jer'UJM, ,19 q{

My Commission Expires: March 31, 2000.

otary Public

-- (SEAL)

ATTACHMENT 1 DISCUSSION OF CHANGES VIRGINIA ELECTRIC AND POWER COMPANY SURRY UNITS 1 AND 2

Discussion of Change Introduction Pursuant to 10 CFR 50.90, Virginia Electric and Power Company requests changes to the Technical Specifications Surveillance Requirement in Table 4.1-1, Item 36, "Reactor Trip Bypass Breakers," for Surry Power Station Units 1 and 2. The Technical Specifications currently require the Reactor Trip Bypass Breakers to be tested "prior to being placed in service" (i.e., racked out to the test position, tested, and then racked in to the connect position to commence Reactor Protection System testing). The proposed changes will allow the bypass breakers to be tested immediately after placing the breaker in service, but prior to commencing Reactor Protection System testing or maintenance. These changes will continue to ensure the operability of the breakers and eliminate unnecessary movement caused by racking the breakers; thus, reducing the wear and tear on the breakers and the possibility of a reactor trip.

The operation of the Reactor Protection System as well as the reactor trip and reactor trip bypass breakersJs not being changed. The proposed changes in the test sequence for the reactor trip bypass breakers continue to provide assurance that the reactor trip bypass breakers will operate as designed. The breakers are designed to mitigate the consequence of any unsafe or improper reactor operation during steady state or transient power operations when the bypass breakers are placed in service for reactor trip system testing or required maintenance. Therefore, the proposed changes to the reactor trip bypass breaker surveillance testing sequence do not create an unreviewed safety question.

Background

Current Licensing Basis In response to the 1983 A TWS event at the Salem Nuclear Generating Station, the NRC issued Generic Letter (GL) 83-28, "Required Actions Based on Generic Implications of Salem A TWS Events." Item 4.3 of this letter became the subject of NRC GL 85-09, "Technical Specifications for Generic Letter 83-28, Item 4.3," which required the industry to enhance the maintenance and testing of the reactor trip and reactor trip bypass breakers.

Virginia Electric and Power Company submitted proposed Technical Specifications changes in accordance with the guidance of GL 85-09. These changes revised the operability and surveillance requirements to ensure appropriate actions for inoperable breakers or trip devices and for complete testing of the breakers. The NRC approved the changes for Surry Units 1 and 2 on February 17, 1988 in amendments 117 and 117 and a subsequent revision to the surveillance requirements on February 5, 1990 in Amendments 137 and 137.

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Design Basis The reactor trip circuit breakers and their associated switchgear are designed to channel electricity to the rod control cabinet. The reactor trip switchgear consists of four circuit breakers in a series/parallel arrangement. A bypass breaker is connected in parallel with its respective reactor trip breaker. The bypass breakers are interlocked so that only one bypass breaker can be closed at a given time, and permit online testing of the reactor trip breakers without shutting down the reactor. In addition to the interlock, procedural controls have been established to prevent closing both reactor trip bypass breakers at the same time for testing or maintenance.

The safety-related function of the reactor trip and bypass breakers is to interrupt power to the control rod drive mechanisms (CRDMs) on command from a reactor trip signal.

Interruption of power to the CRDMs causes the control rods to fall by gravity into the reactor core causing the reactor to shut down.

The reactor trip circuit breaker elements are Westinghouse Type DB-50 horizontal drawout, 600 volt rated, 1600 ampere frame power air circuit breakers. The breaker interfaces electrically- with the switchgear cell. components through its six primary disconnecting contacts and its secondary contact assembly. Each element has three designated positions (Disconnect, Test, and Connect) in the switchgear cell.

Discussion Item 36 of Table 4.1-1 requires a Channel Functional Test of the reactor trip bypass breakers. Note 1 for Item 36 states that a remote manual undervoltage trip is required prior to placing the bypass breaker in service. Recently, a compliance issue was identified concerning the testing sequence of the reactor trip bypass breakers. It was identified that the periodic test procedures did not verify the manual undervoltage trip prior to placing the bypass breaker in service. From approximately June 9, 1986 until the verbatim compliance issue was identified in October 1997, the reactor trip bypass breaker manual undervoltage trip was tested immediately after closing the normally racked-in (connect) breaker.

In order to accommodate seismic qualification of the reactor trip and bypass breaker and cubicle, the reactor trip bypass breakers are normally racked-in and open. Only during surveillance or maintenance was a reactor trip bypass breaker closed. The remote manual undervoltage trip test of the reactor trip bypass breaker was performed with the breaker racked-in, thus, when the breaker was closed to perform the manual undervoltage trip test the breaker was actually in service for that very short period of time. This testing sequence was identified in Deviation Report S-97-3167 as not being in compliance with the Technical Specification Surveillance Requirement Table 4.1-1, Item 36, Note 1, which requires a remote manual undervoltage trip of the breaker prior to placing the bypass breaker in service. Licensee Event Report 81-97-011-00 dated Page 2 of 5

November 26, 1997 and Non-cited Violation 50-280, 281/97012-04 were also issued to address this issue.

In response to the verbatim -compliance issue with Technical Specifications, Surry modified the test sequence. The modified test sequence requires the reactor trip bypass breaker to be racked from the normal connect position to the test position. The breaker is then closed and tripped manually using the undervoltage device, and then returned to the connect position, whereby the bypass breaker is placed in service (closed) for testing or maintenance to commence. This current test sequence requires racking the breakers to the test position and then back to the normal connect position, which increases the wear and tear on the reactor trip bypass breakers.

The proposed changes to the Technical Specifications notation will require testing the reactor trip bypass breakers immediately after placing the reactor trip bypass breaker in service. In addition, the proposed notation will ensure that the bypass breaker is tested prior to performing testing of the reactor trip system or required maintenance. These changes will continue to assure bypass breaker operability and eliminate unnecessary movement (racking the breaker) for testing; thus reducing the wear and tear of the reactor trip bypass breakers and possible breaker alignment problems when racking the breakers in and out. Reducing unnecessary movement will limit the potential for an inadvertent reactor trip due to possible breaker misalignment.

The circuit breaker elements weigh approximately 340 pounds and are awkward to move on the breaker cell rails. Mishandling of the breaker elements can cause severe damage to the equipment. Damages reported by the Westinghouse Vendor Technical Manual have included bent cell positioning stop brackets, breaker element positioning levers, breaker release latches, miscellaneous brackets, pins and stops as well as misalignments of the cell rails and the breaker elements to the cells. Proper and limited handling of the circuit breaker elements will increase the longevity of the equipment and will contribute directly to its reliable operation.

• Additionally, the prevailing interpretation before identification of the compliance issue was based upon the application of the associated action statements. Table 3.7-1, "Reactor Trip Instrument Operating Conditions," Item 18A, allows a reactor trip breaker to be bypassed by closure of the associated bypass breaker, for two hours for surveillance testing. Thus, a reactor trip breaker is effectively inoperable and in an Action Statement as soon as the respective bypass breaker is closed. Since the bypass breaker would have been immediately tested upon closure by verifying that the undervoltage trip caused it to trip, Note 1 was believed to be fully satisfied.

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• e The proposed testing sequence of the reactor trip bypass breakers starting with the

.breakers in tMeir normal connect position is as follows:

• Close the bypass breaker

• Immediately trip the bypass breaker using the remote manual undervoltage trip mechanism (Immediately is intended to be as soon as reasonably practicable, without delay after closing the bypass breaker)

• Close the bypass breaker

• Commence reactor trip system testing or required maintenance This testing sequence adequately establishes the operability of the breaker and eliminates the unnecessary movement of the bypass breakers.

Specific Changes In order to accomplish the test in this manner and clarify the notations, the Technical Specifications will be revised as noted below:

• Revise Note (1) for Item 36, "Reactor Trip Bypass Breaker," in Table 4.1-1 as noted below:

(1) "Remote manual undervoltage trip immediately after placing the bypass breaker into service, but prior to commencing reactor trip system testing or required maintenance."

Safety Significance The proposed change in test sequence for the reactor trip bypass breakers continues to provide assurance that the reactor trip bypass breakers will operate as designed to mitigate the consequence of any unsafe or improper reactor operation during steady state or transient power operations when the bypass breakers are placed in service for reactor trip system testing or required maintenance.

a) Operation and testing of the reactor trip breakers does not increase the probability of an accident or malfunction of equipment important to safety previously evaluated in the safety analysis report.

The testing sequence will continue to ensure that the reactor trip system will be operable to mitigate the consequences of any unsafe or improper reactor operation during steady state or transient power operations. During the short period of time the breaker is closed before the undervoltage trip device test, the operability of the breaker is established based on satisfactory Page 4 of 5

breaker testing conducted during the previous surveillance interval.

Although the breaker is placed in service for a very short time before it is tested, the breaker is tested as soon as practicable to verify operability prior to performing testing of the reactor trip system or required maintenance.

Therefore, the proposed test sequence does not increase the probability of occurrence or the consequences of any previously analyzed accident.

b) The proposed Technical Specifications do not create the possibility of an accident or malfunction of a different type than any evaluated previously in the safety analysis report.

The proposed test sequence change does not alter the actual test performed to establish operability of the reactor trip bypass breakers. The bypass breakers will be proven operable prior to reactor trip system testing or required maintenance. During the short period of time the breaker is closed before the local undervoltage trip device test, the operability of the breaker is established based on satisfactory breaker testing conducted during the previous surveillance interval. Although the breaker is placed in service before it is tested, the breaker is tested as soon as practicable to verify operability prior to performing testing of the reactor trip system or required maintenance. Therefore, it is concluded that no new or different kind of accident or malfunction from any previously evaluated has been created.

c) The proposed Technical Specifications change does not result in a reduction in margin of safety as defined in the basis for any Technical Specifications.

The proposed change. in the reactor trip bypass breaker test sequence provides assurance that the reactor trip system remains operable during normal operations or during reactor trip system testing and reactor trip breaker maintenance to mitigate the consequences of any unsafe or improper reactor operation. Therefore, the proposed change in the test sequence for the reactor trip bypass breaker does not reduce the margin of safety.

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