TXX-9913, LAR 99-005 to Licenses NPF-87 & NPF-89,revising EDG Start to Emergency Start Instead of Normal Start Following Loss of Offsite Power

LAR 99-005 to Licenses NPF-87 & NPF-89,revising EDG Start to Emergency Start Instead of Normal Start Following Loss of Offsite Power

ML20212J417
Person / Time
Site:	Comanche Peak
Issue date:	06/23/1999
From:	Terry C, Walker R TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC)
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20212J424	List: ML20212J425 TXX-9913, LAR 99-005 to Licenses NPF-87 & NPF-89,revising EDG Start to Emergency Start Instead of Normal Start Following Loss of Offsite Power
References
TXX-99134, NUDOCS 9907010158
Download: ML20212J417 (7)

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• Femme Log # TXX-99134

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File # 10010 916 r r Ref. # 10CFR50.90 OCFR50.36a 7UELECTRIC r

June 23,1999 i

C.I. mees'Dury i Senior Mce PresMent

& PrincipalNuclear Oficer U. S. Nuclear Re Commission Attn: . Document ontro bulator[ Desk Washington, DC 20555 -

SUBJECT:

COMANCHE PEAK STEAM ELECTRIC STATION (CPSES)

DOCKET NOS. 50-445 AND 50-446 '99-005 LICENSE REVISION ASSOCIATED SURVEILLANCE AMENDMENT WITH EMERGE REQUEST (LAR)NCY DIESEL GENER

- Gentlemen:

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- Pursuant to 10CFR50.90, TXU Electric

• hereby requests an amendment to the CPSES

. Unit 1 Operating License (NPF-87) and CPSES Unit 2 Operating License (NPF-89) by incorporating the attached change into the CPSES Units 1 and 2 Technical Specifications. This change request applies to both units.

The proposed change will revise the Emergency Diesel Generator's (EDG) start be an

emergency start" instead of a " normal start" following loss of offsite power. This License Amendment Request (LAR) revises Surveillance Requirement (SR) 3.8.1.13 and associated Bases to verify that each EDG automatic trips, except for engine overspeed and generator differential current, are bypassed on an EDG emergency start logic initiation, whether the emergency start initiation be actual or simulated. The EDG emergency start logic is initiated in response to either a loss of voltage on the emergency bus or a Safety. Injection actuation signal.

Attachment 1 is the required affidavit.~ Attachment 2 provides a detailed description of the proposed change, a safety analysis of the change, and TXU Electric's determination

- that the proposed change does not involve a significant hazard consideration. l Attachment 3 provides the affected Technical Specification page, marked-up to reflect '

the proposed change.

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PDR ADOCK 05000445 P PDR

• TXU Electric was formerly TU Electric. A license amendment request (LAR 99-003) was submitted per TXX-99122, dated May 14,1999, to revise the company name contained in the CPSES operating licenses.

COMANCilE PEAK SIEAM ELECTRIC STATION P.O. Box 1002 Glen Rose. Texas 76043-1002

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L TXX-99134 l

Page 2 of 2 TXU Electric requests approval of the proposed License Amendment by September 20, 1999. The diesel generator modifications associated with this change will be l Implemented on Unit i during 1RFO7, which is scheduled to begin on September 20, 1999. Similar modifications were performed on Unit 2 during 2RFO4; however, the Unit 2 ,

modifications were made for a different reason than tiie underlying reason for this change l request and did not involve a change to the Technical Specifications. Subsequent to the l Unit 2 modification implementation, a deficiency resolution associated with the feedwater i line break (FWLB) determined that the newly installed modification would be credited as part of the FWLB deficiency resolution. The Unit 2 design change was completed in i 2RFO4, and implementation of the surveillance requirement will be completed by 2RFO5. l In accordance with 10CFR50.91(b), TXU Electric is providing the State of Texas with a copy of this proposed amendment.

l This communication contains no new commitments or revised commitments. Should you have any questions, please contact Mr. Manu C. Patel at (254) 897-0139.

Sincerely, f0 &

C. L. Terry stG2. b By: Roge2.' Walker ~

l Regulatory Affairs Manager l MCP/mcp Attachments: 1. Affidavit

2. Description and Assessment

3. Affected Technical Specification page (marked-up pages) c- E. W. Merschoff, Region IV J. l. Tapia, Region IV Resident inspectors, CPSES l

D. H. Jaffe, NRR  !

Mr. Authur C. Tate Bureau of Radiation Control Texas Department of Public Health l 1100 West 49th Street l Austin, Texas 78704

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Attachment 1 to TXX-99134 Page 1 of 1 1

- UNITED STATES OF AMERICA )

, NUCLEAR REGULATORY COMMISSION J l In the Matter of )

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TXU Electric Company ) Docket Nos. 50-445

) 50-446 (Comanche Peak Steam Electric Station, ) License Nos. NPF-87 Units 1 & 2) ) NPF-89 AFFIDAVIT Roger D. Walker being duly sworn, hereby deposes and says that he is Regulatory Affairs Manager of TXU Electric, the licensee herein; that he is duly authorized to sign and file with the Nuclear Regulatory ' Commission this License Amendment Request 99-005; that he is familiar with the content thereof; and that the matters set forth therein are true and correct to the best of his knowledge, information and belief.

W Rogeft. Walker Regulatory Affairs Manager STATE OF TEXAS )

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COUNTY OF Johnson. )

Subscribed anri sworn n before me, on this 83 day of anth 1999, v i g [ hgg l l CARCi.YN L COSDJTINO Notary Ptplic I i

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l ATTACHMENT 2 to TXX-99134 l DESCRIPTION AND ASSESSMENT l

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i Attachment 2 to TXX-99134 Page 1 of 3 DESCRIPTION AND ASSESSMENT l

l. BACKGROUND Design Basis Accidents (DBAs) such as the American Nuclear Society (ANS) Condition IV feedwater line break (FWLB) are assumed to result in a loss of offsite power (LOOP) prior to the generation of a Safety injection Actuation Signal (SIAS). The Emergency Diesel Generators (EDGs) are required to start and load upon detection of the loss of offsite power condition; a second EDG start signal is initiated when the SIAS is generated.-

EDG " emergency" starts are required for mitigation of DBAs. An EDG start on a SIAS is denoted as an "emergene,f start, which means that several noncritical EDG protective trip functions and interlocks are bypassed. During a review of plant design documents, it was discovered that the EDG start on a LOOP condition is denoted as a " normal" start, which means that none of these noncritical protective trip features and intenocks are bypassed. Some of these EDG protective trip features are non-safety-related and their operation will also trip the EDG.

- To resolve this condition, a design modification was initiated to change the EDG start upon detection of a LOOP condition from a ' normal" start to an " emergency" start.

Currently per SR 3.8.1.13, the verification that noncritical trips are bypassed was performed only for a LOOP in conjunction with a SIAS. Because the EDGs are also required to start in an emergency mode to mitigate a condition IV accident (FWLB) upon a LOOP condition with no concurrent SIAS, the surveillance requirement SR 3.8.1.13, needs to be revised accordingly.

II. DESCRIPTION OF TECHNICAL SPECIFICATIONS CHANGE REQUEST This license amendment request (LAR) revises SR 3.8.1.13 and its associated Bases to verify that each DG's automatic trips, except for the engine overspeed trip and un:,

generator differential current trip, are bypassed on an actual or simulated (1) loss of voltage signal on the emergency bus, and (2) an Si actuation signal.

Ill. . ANALYSIS This surveillance is required to demonstrate that EDG noncritical protective functions  !

(e.g., high Jacket water temperature trip) are bypassed when the EDGs are operated to mitigate DBAs. The EDG availability to mitigate the DBA is more critical than protecting the engine against minor problems that are not immediately detrimental to EDG

- operation. This is a conservative change in that the surveillance previously required the trip bypass verification only for a LOOP in conjunction with a SI, whereas this

- revision' requires the trip bypass verification both for the LOOP by itself and for the Si by itself.

IV SIGNIFICANT HAZARDS CONSIDERATIONS ANALYSIS TXU Electric has evaluated whether or not a significant hazards consideration is involved with the proposed changes by focusing on the three standards set forth in i 10CFR50.92(c) as discussed below:

1. Do the proposed changes involve a significant increase in the probability or 4

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' Attachment ' 2 to TXX-99134 i Page 2 of 3 l consequences of an accident previously evaluated?

The emergency diesel generators are used to support mitigation of the consequences of an accident and are not considered to be initiator of any previously analyzed accident. Revising the surveillance to verify the bypass of non-critical EDG trips on both LOOP and SI separately enhances the ability of the EDG to perform its safety function by ensuring continued operation during DBAs.

Therefore, this change will not result in an increase in the probability or consequences of an accident previously evaluated.

2. Do the proposed changes create the possibility of a new or different kind of accident from any accident previously evaluated?

The proposed change to the surveillance requirement involves an EDG start circuit modification. The circuit modification has been previously installed on Unit 2 during 2RF04 for reasons other than the issue associated with the FWLB.

As a part of the Unit 2 Installation a 50.59 evaluation was performed and it was determined that the modification did not represent an unreviewed safety question. The modification similar to Unit 2 will be implemented on Unit 1 and therefore, as concluded in the safety evaluation for the original modification, no new failure mechanisms will be introduced by the proposed change. The EDGs are designed to provide electrical power to equipment important to safety in the event of a loss of offsite power. The proposed change to the SR enhances the confidence that the EDGs will start and fulfill their safety related function.

Therefore, this change will not create the possibility of a new or different kind of accident from any accident previously evaluated.

3. Do the proposed changes involve a significant reduction in a margin of safety?

The proposed change will not alter any accident analysis assumptions, initial conditions, or results. Revising the surveillance requirement to verify the EDG trip bypass for the LOOP and SI separately will enhance the confidence that the EDG starts as assumed in the safety analyses and does not create any new failure scenarios and no margin lo reduced.

Therefore, this change does not involve a significant reduction in a margin of safety.

In summary. TXU Electric has determined that the revised surveillance for the EDG trip bypass verification does not involve a significant hazard consideration and will not be of potential detriment to the public health and safety.

V. ENVIRONMENTAL EVALUATION .

TXU Electric has determined that the proposed amendment would change requirements with respect to the installation or use of a facility component located within the restricted area, as defined in 10CFR20, or would change an inspection or surveillance requirement. TXU Electric has evaluated the proposed changes and has determined that the changes do not involve (1) a significant hazards consideration, (2) a significant l

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Attachment 2 to TXX-99134 Page 3 of 3 change in the types or significant increase in the amounts of any effluent that may be released offsite, or (3) a significant increase in individual or cumulative occupational radiation exposure. Accordingly, the proposed changes meet the eligibility criterion for categorical exclusion set forth in 10CFR51.22(c)(9). Therefore, pursuant to 10CFR51.22(b), an environmental assessment of the proposed change is not required.

I VI. REFERENCES None ,

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