ML20199K444

Application for Amend to License DPR-55,adding one-time Allowance Through Operating Cycle 9 to Surveillance Requirement 4.4.3.2.1.b to Perform Stroke Testing of PORVs in Mode 5 Rather than Mode 4,as Currently Required

ML20199K444
Person / Time
Site:	Sequoyah
Issue date:	11/21/1997
From:	James Smith TENNESSEE VALLEY AUTHORITY
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20199K447	List: ML20199K444 ML20199K457
References
NUDOCS 9712010124
Download: ML20199K444 (7)

Text

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Tennessee Valley Authortty, Post Offee Pax 2000, sotty-Da'sy, Terresa,37379 2000 November 21, 1997 TVA-SQN-TS-97-05 10 CFR 50.90 U.S. Nuclear Regulatory Commission ATTN Document Control Desk Washington, D. C.

20555 Gentle en In the Matter of

)

Docket No.

50-327 Tennessee Valley Authority

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SEQUOYAH NUCLEAR PLANT (SQN) - UNIT 1 - TECHNICAL SPECIFICATION (TS) CHANGE NO. 97-05, " UNIT 1 PRESSURIZER POWER OPERATOR RELIEF VALVE (PCRV) SURVEILLANCE TESTING" In accordance with the provisions of 10 CFR 50.4 and 50.90, TVA is submitting a request for an amendment to SON's license DPR-77 to change the TSs for Unit 1.

The proposed change adds a one-time allowance through operating Cycle 9 to Surveillance Requirement (SR) 4.4.3.2.1.b to perform stroke testing of the

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PORVs in Mode 5 rather than Mode 4, as currently required.

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TVA has determined that there are no significant hazards considerations associated with the proposed change and that if' the change is exempt from environmental review pursuant to the provisions of 10 CFR 51.22 (c) (9).

The SON Plant Operations Review Committee and the SON Nuclear Safety Review Board have reviewed this proposed change and determined that operation of SON Unit 1, in accordance with the proposed change, will not endanger the health and safety of the public.

Additionally, in accordance with 10 CFR 50.91(b) (1 TVA is sending a copy of this letter and enclosures to the Tennessee State Department of Public Health.

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9712010124 971121 PDR ADOCK 05000327 P

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U.S. Nuclear Regulatory Commission Page 2 November 21, 1997 l to this letter provides the description and evaluation of the prop sed change.

This includes TVA's determination that the proposed change does not involve a significant hazards consiueration, and is exempt from cnvironmental review. contains copies of the appropriate TS pages from Unit 1 marked-up to show the proposed change. forwards the revised TS pages for Unit 1, which incorporates the proposed change.

TVA requests that the proposed TS be processed in an urgent manner.

The current surveillance performed in Mode 4 remains in frequency until January 18, 1998, at which time the requested change needs to be in place.

At the expiratica of the test frequency, Action "a" of TS 3.4.3.2 requires the block valves of the PORVs to be closed to allow continued operation.

TVA believes that the performance of this system realignment is inappropriate for the specific plant conditions.

While continued power operation is allowed, continued operation without the automatic function of the PORV system is not considered to bc an optimal configuration from a nuclear safety standpoint.

TVA requescs that the revised TS be made ef fective within seven days of NRC approval.

If you have any questions about this change, please telephone me at (423) 843-7170 or J.

D.

Smith at (423) 843-6672.

Sincerely, NW~

J.

D.

Smith Site Licensing Supervisor Subscribed gnd sworn tp before me r'6iB day of/)vN/gv L%ghis c2/Lu YM 00%da Notaff Public d

My Commission Expires 8 W.2//ff[

JDS:PGT:PMB Enclosures l

cc:

See page 3

U.S.'

Nuclear Regulatory Commission Page 3_

j November 21, 1997 i

cc (Enclosures):

Mr. R._W..Hernan, Project Manager Nuclear Regulatory Commission One White' Flint, North l

11555 Rockville Pike Rockville, Maryland 20052-2739

-Mr. Michael H. Mobley, Director (w/o Enclosures)

Division of Radiological Health

. Third Floor L&C Annex

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401 Church Street Nashville, Tennessee 37243-1532 NRC Resident l

Sequoyah Nuclear Plant 2600 Igou Ferry Road Soddy-Daisy, Tennessee 37379-3624 Regional Administrator U.S. Nuclear Regulatory Commission Region II Atlanta Federal Center i

61 Forsyth St.,

SW, Suite 23T85 Atlanta, Georgia 30303-3415 L

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ENCLOSURE 1 TENNESSEE VALLEY AUTHORITY SEQUOYAH NUCLEAR PLANT (SQN)

UNITS 1 DOCKET No. 327 PROPOSED TECHNICAL SPECIFICATION (TS) CHANGE TS-97-05 DESCRIPTION AND EVALUATION OF THE PRCPOSED CHANGE I.

DESCRIPTIOil OF THE PROPOSED CHANGE TVA proposes to modify the Sequoyah Nuclear Plant (SQN)

Unit 1 TSs by making a one-time change to 1, 3.4.3.2 by revising Surveillance Requirement (SR) 4.4.3.2.1.b to allow for Unit 1 Cycle 9 operation only, meeting the surveillance by operating the valve through one complete cycle of full travel dur.ng Mode 5 with the pressurizer in saturated condition and temperature greater than or equal to 420 degrees Fahrenheit.

In addition, any entry into Mode 4 during the Unit 1 Cycle 9 operation will require performance of this surveillance in this mode.

II.

REASON FOR THE PROPOSED CHANGE During the recent Unit 2 Cycle 8 refueling outage, FON discovered that TS SR 4.4.3.2.1.b had not been performed on the PORVs in Mode 4 as required. Unit 2 was subsequently cooled back down to Mode 4 to perform the SR. SON missed this SR as a result of less than adequate change management during implementation of the TSs. Two dissimilar SRs (SR 4.0.5 requires quarterly testing plus 18-month stroke timing in Mode 5 while SR 4.4.3.2.1.b requires full stroking during Mode 4) are performed in one surveillanco instruction and are scheduled by one surveillance matrix identification number.

SR 4.4.3.2.1.b requires each PORV to be demonstrated operable at least once per 18.aonths (typically during refueling outages) by operating the valve through one complete cycle of full t.tavel during Mode 4.

It was identified during the extent of condition review that both PORVs on Unit 1 did not have a full stroke performed in Mode 4 during the Unit 1 Cy.;1e 8 refueling outage.

TVA has determined that while a full stroke has been performed on the PORVs in Mode 5, with conditions similar to those that could be present in Mode 4, the specific requirement to El-1

test in Mode 4 during the Unit 1 Cycle 8 refueling outage was not met.

Further research has determined that the valves were tested during Mode 4 in a forced outage on March 2, 1996.

Therefore, testing remains in frequency until January 18, 1998, utilizing the 25 percent extension interval of TS 4.0.2.

At the expiration of the test frequency, Action "a" of TS 3.4.3.2 requires the block valves of the PORVs to be closed to allow continued operation.

TVA believes that the performance of this system realignment is inappropriate for the specific plant conditions.

While continued power operation is allowed, continued operation without the automatic function of the PORV system is not considered to be an optimal configuration from a nuclear safety standpoint.

Accordingly, TVA is requesting a one time change, through operating Cycle 9, to SR 4.4.3.2.1.b to allow performance of stroke testing of the PORVs in Mode 5 rather than Mode 4 as currently required (note that Unit 1 Cycle 9 refueling outage is currently scheduled for September 1998).

III.

SAFETY ANALYSIS As stated in the TS Bases, the PORVs and steam bubbit function to relieve reactor coolant system pressure during all design transients up to and including the design stel load decrease with steam dump.

Operation of the PORVs minimizes the undesirable opening of the spring-loaded pressurizer code safety valves.

Each PORV has a remotely operated block valve to provide positive shutoff capability should a relief valve become inoperable.

The PORVs also function to remove noncondensables or steam from the pressurizer.

The Unit 1 PORVs were full stroke tested in Mode 5 with a steam bubble in the pressurizer.

The Mode 5 pressurizer condition that existed at the time the valves were stroked was-Pressure approximately 315 psia and tempera'sr+ approximately 422 degrees Fahrenheit.

This cor.dition ecmpares favorably to that which existed when the valves were last tested in Mode 4 (typical of the pressurizer in the low end of Mode 4):

Pressure approximately 366 psia and temperature approximately 436 degrees Fahrenheit.

The pressurizer Mode 4 condition has been previously noted at the 420 degrees Fahrenheit, 309 psia value in testing, bounding the current tested Mode 5 condition.

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A full stroke of the PORV in these Mode 5 conditions illustrate the PORVs performance in as close to the normal operating conditions as is practicable and are equivalent to the conditions required by SR 4.4.3.2.1.b.

Based on the above, TVA has determined that there is l

no safety consequences to operate with block valves open as the PORVs are considered fully functional.

In addition, a safety enhancement is gained to

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operate with the block valves open allowing the i

automatic function of the PORVs to be utilized.

Closing the block valves presents automatic control of the PORVs.

Unnecessarily closing these valves would increase the challenges to the code safety valves for overpressure events.

Automatic operation minimizes the undesirable opening cf the spring loaded pressurirer cod? safety va.v.s.

Cimilarly reducing power and bringing the plant tc Mode 4 conditions to perform testing subjects the plant to an operating transient that in itself has negative risk.

IV.

NO SIGNIFICANT HAEARDS CONSIDERATION DETERMINATION TVA has concluded that operation of SON Unit 1 in accordance with the proposed change to the TSs [or operating license (s)) does not involve a significant hazards consideration.

TVA's conclusion is based on its evaluation, in accordance with 10 CFR 50. 91 (a) (1), of the three standards set forth in 10 CFR 50.92(c).

A.

The proposed unendment does not involve a significant increase in the probability or consequences of an accident previously evaluated.

The possibilit.y of occurrence or the consequences for an accident or malfunction of equipment is not increased as the PORVs have been tested under representative conditions and are fully functional.

As such, the PORVs are expected to open and close on demand.

In addition, the block valves are still available to mitigate flow from the PORVs.

B.

The proposed amendment does not create the possibility of a new or different kind of accident from any accident previously evaluated.

A possibility for an accident or malfunction of a different type than any evaluated previously in the El-3

4 safety analysis report may be created; or the possibility for an accident or malfunction of a different type does not exist as the PORVs have been tested under representative conditions and are fully functional.

No new failure modes have been introduced.

C.

The proposed amendment does not involve a significant reduction in a margin of safety.

l The margin of safety has nct been reduced.

The PORVs are fully functional.

However, literal compliance with the TS requires the block valves to be closed.

The margin of safety will be increased if continued operation is allowed with the block valves open.

V.

ENVIRONMENTAL IMPACT CONSIDERATION The proposed change does not involve a significant

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hazards consideration, a significant char.ge in the types of or significant increase in the amounts of any effluents that may be released offsite, or a significant increase in individual or cumulative i

occupational radiation exposure.

Them fore, the proposed change meets the eligibility criteria for

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categorical exclusion set forth in 10 CFR 51.22 (c) (9).

Therefore, pursuant to 10 CFR 51.22 (b),

an environmental assessment of the proposed change is not required.

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