05000445/LER-2002-001, For Comanche Peak Steam Electric Station Unit 1 Regarding Condition Prohibited by Technical Specifications

For Comanche Peak Steam Electric Station Unit 1 Regarding Condition Prohibited by Technical Specifications

ML023250362
Person / Time
Site:	Comanche Peak
Issue date:	11/15/2002
From:	Walker R TXU Energy, TXU Generation Co, LP
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
CPSES-200203686, TXX-02171 LER 02-001-00
Download: ML023250362 (7)

LER-2002-001, For Comanche Peak Steam Electric Station Unit 1 Regarding Condition Prohibited by Technical Specifications

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(iii) 10 CFR 50.73(a)(2) 10 CFR 50.73(a)(2)(v), Loss of Safety Function
4452002001R00 - NRC Website

text

V 9%TXU TXU Energy Comanche Peak Steam Electric Station PO Box 1002 (E01)

Glen Rose,TX 76043 Tel 254 897 8920 Fax. 254 897 6652 lance terry@txu corn C. Lance Terry Senior Vice President &

Principal Nuclear Officer Ref. # 10CFR50.73(a)(2)(i)(B).

CPSES-200203686 Log # TXX-02171 File # 10200 November 15, 2002 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555

SUBJECT:

COMANCHE PEAK STEAM ELECTRIC STATION (CPSES)

DOCKET NO. 50-445 AND 50-446 CONDITION PROHIBITED BY TECHNICAL SPECIFICATIONS LICENSEE EVENT REPORT 445/02-001-00 Gentlemen:

Enclosed is Licensee Event Report (LER) 02-001-00 for Comanche Peak Steam Electric Station Units 1 and 2, "Emergency Diesel Generators Inoperable While Paralleled to Offsite Source."

A member of the STARS (Strategic Teaming and Resource Sharing) Alliance Callaway

• Comanche Peak

• Diablo Canyon

• Palo Verde South Texas Project Wolf Creek

VTXU TXX-0217 1 Page 2 of 2 This communication contains no new licensing basis commitments regarding CPSES Units 1 and 2.

Sincerely, TXU Generation Company LP By:

TXU Generation Management Company LLC, Its General Partner C. L. Terry Senior Vice President and Principal Nuclear Officer By:

61 01 C,

Ro rD. Waller Regulatory Affairs Manager GLM/gm Enclosures c -

E. W. Merschoff, Region IV W. D. Johnson, Region IV D. H. Jaffe, NRR Resident Inspectors, CPSES

Enclosure to TXX-02171 NRC FORM 366 U.S. NUCLEAR REGUILATORY COMMISSION APPROVED BY OMB NO. 3150-0184 (7-2001)

EXPIRES 0713112004 the NRC may not conduct or sponsor. and a person Is not required to respond to. the information collection.

Facility Name (I)

Docket Numnber (2)

Page (3)

COMANCHE PEAK STEAM ELECTRIC STATION UNIT 1 05000445 1 OF 5 Title (4)

CONDITION PROHIBITED BY TECHNICAL SPECIFICATIONS Event Dare (5)

LER Number (6) 1 Ret Date (7)

Other Facilities Involved (8)

Month Day Year Year I

Sequeia Revision Month Day Year Facility Name Docket Nunbers ixNumber I

NumberCPSES UNIT 2 05000446 09 20 02 02 001 00 11 15 02.

05000 Operati 1

ireport is subnnted purmwant to the reqets of 10 CFR: (Check all that apply) (II) E Mode (9) 1 20.2201(b) 20.2203(a)(3Xi)

I 50.73(a)(2Xi)(C) 50.73(aX2)(vii)

Power 20.2201 (d) 20.2203(a)(3)(ii) 50.73(aX2XiiXA) 50.73(a)(2flviii)(A)

Level 100 20.2203(a)(I) 20.2203(aY4) 50.73(a(2)(iiWB) 50.73(a)(2Wviii)(B) 20.2203(afl2)(i) 50.36(c)(2)(i)(A) 50.73(a)(2)(iii) 50.73(a2Wix)(A) 20.2203(a)(2)(ti) 50.36(c)( )(ii)(A) 50.73(aO 2)(iv)A) 50.72(a)(2gx) 20.2203(a)(2Wiii) 50.36(c)(2) 50.73(a)(2XvXA) 73.71(a)(4) 20.2203 (a'()(v) 50 46(a)(30ii) 50.73(a)(2)(y)(B) 73.71 (a)(5) 20.2203(a)(2)(v) 50 73(a)(2Xi)(A) 50.73(aX2)(v)(C)

OTHER 20.2203(a)(2)(vi)K 50 73(a)(2)(i)(B)

=

50.73(a)(2)(v)(D)

Specify in Abstract below or 5 _________

in =

(Ifnmore space i required, use additional copies of NRC Fonr 366A) (17)

I.

DESCRIPTION OF REPORTABLE EVENT A.

REPORTABLE EVENT CLASSIFICATION

Any operation or condition which was prohibited by the plant's Technical Specifications.

B.

PLANT OPERATING CONDITIONS PRIOR TO THE EVENT On September 20, 2002, CPSES Units 1 and 2 were in Mode 1, Power Operation, operating at 100 percent power.

C.

STATUS OF STRUCTURES, SYSTEMS, OR COMPONENTS THAT WERE INOPERABLE AT THE START OF THE EVENT AND THAT CONTRIBUTED TO THE EVENT Not Applicable - There were no structures, systems, or components that were inoperable at the start of the event which contributed to this event.

D.

NARRATIVE SUMMARY OF THE EVENT, INCLUDING DATES AND APPROXIMATE TIMES On July 23, 2002, during review of a license change request submitted by another utility related to on-line testing of the EDGs [EIIS:(DG)], CPSES Engineering personnel (Utility, Non-Licensed) noted a potential operability concern with the EDGs when operated in parallel with offsite power. Additionally, CPSES Regulatory Affairs personnel (Utility, Non-Licensed) identified that another utility declared their EDGs inoperable when paralleled with offsite power, but CPSES did not.

As a precautionary measure, procedures were changed on July 30, 2002, to declare an EDG paralleled to offsite power inoperable. A detailed analysis was initiated by CPSES Engineering to complete the determination of EDG operability during the current testing configuration. The assessment included postulated design basis scenarios resulting in Safety Injection (S1) initiation and/or a Loss of Offsite Power (LOOP) when an EDG is operating in normal mode in parallel with offsite power (i.e., the typical EDG test configuration).

Electrical protective device coordination, system loading, and short circuit current levels were needed to complete the assessment. A separate review was initiated by CPSES Engineering to determine if the EDGs had been operated in parallel with offsite power for greater than the Completion Times of CPSES Technical Specifications.

I- -----

NMC rUKM J00A (I-.W9I

Enclosure to TXX-02171 (Ifmore space is required, use additional copies ofNRC Fosm 366A) (17)

On September 20, 2002, CPSES Engineering's assessment had reached a point sufficient to conclude that the single failure criterion of IEEE Standard 379-1972 is not satisfied when an EDG is operated in parallel with offsite power in Modes 1 - 4. The operation of the EDGs in parallel with an offsite power source is a unique condition. The under voltage relay [EIIS:(27)] to detect the offsite power source non-availability is located at the 6.9kV bus [EUIS:(BU)] on the 6.9KV side of the offsite source transformers [EIIS:(XFMR)]. When an EDG is operating in parallel with offsite power and the offsite power is lost, the undervoltage relays will not detect the loss of offsite power. Additionally, because the offsite power source feeds both trains of the safety related buses, as allowed by General Design Criterion (GDC)- 17, the parallel operation of an EDG also results in a condition where an EDG may be feeding the opposite train bus. GDC-17 is unique in that the non-safety related offsite source, which feeds both of the safety related busses, is the recognized preferred source.

It was determined that the CPSES Unit 1 and 2 EDGs had been operated in parallel with offsite power on some occasions in the past for a time period greater than the Completion Time allowed to complete the Required Actions of the applicable Technical Specification, without the required actions being performed. CPSES Technical Specification 3.8.1, Condition B.1, requires that with one EDG inoperable, Surveillance Requirement 3.8.1.1 is to be performed for the required offsite circuit(s) within one hour. Surveillance Requirement 3.8.1.1 requires verification of correct breaker alignment and indicated power availability for each required offsite circuit. If Condition B. 1 is not met, then Condition G. 1 requires being in Mode 3 within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />. Normally, an EDG is paralleled to offsite power in a test configuration for approximately 2 to 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />. However, review of past EDG run time data indicates that the EDGs on Units 1 and 2 operated on some occasions in the past while paralleled to an offsite source for longer than 7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br /> (allowed time of Condition B.1 plus Condition G.1). Therefore, the EDGs were determined to have been inoperable in the past in violation of Technical Specification requirements.

E.

THE METHOD OF DISCOVERY OF EACH COMPONENT OR SYSTEM FAILURE, OR PROCEDURAL OR PERSONNEL ERROR CPSES Engineering personnel (Utility, Non-Licensed) determined, during an evaluation conducted to address a concern related to operating the EDGs in parallel with offsite power, that the EDGs had been inoperable in the past for a period of time that exceeded Technical Specification completion times.

NRC FURM 366A (I-200I)

Enclosure to TXX-02171 NRC FOtM 366A U.S. NUCLEAR REGULATORY COMMISSION (1-2001)

LICENSEE EVENT REPORT (LER)

Facility Name ()

Docket LER Number(6)

Page(3)

Year i Sequential GiRevision COMANCHE PEAK STEAM ELECTRIC STATION UNIT 1 05000445 02 Number 050044 I02H[-

001 H- 00 1 4 OF 5 NARRATIVE (If mre space is requred use additua2 copies of (ifn re space is requited. use addiional copies of NRC Form 366A) (17) occurring at the same time was determined to be very small, and any increase in risk due to exceeding the applicable Technical Specification Required Action Completion Time is negligible.

There were no safety system functional failures associated with this event.

Because CPSES has not experienced any plant events when an EDG was aligned for parallel operation with an offsite power source, this event did not adversely affect the safe operation of CPSES Units 1 and 2 or the health and safety of the public.

IV.

CAUSE OF THE EVENT

TXU Energy has determined that the cause of the event was that the uniqueness of the design and the operating restrictions of the CPSES electrical system were not clearly apparent. It was not clearly apparent that parallel operation may cause the EDG under test to feed the loads of the opposite train and that the location of the loss of voltage instruments being on the 6.9KV side of the power transformers may prevent detection of the loss of offsite power if it were to occur during EDG parallel operation. This condition was determined to be unique to EDG operation in parallel with offsite power.

V.

CORRECTIVE ACTIONS

The EDG test procedures for both units have been revised to declare an EDG paralleled to off-site power as inoperable. In this condition, single failure criteria is not required.

VI.

PREVIOUS SIMILAR EVENTS

There have been no previous similar events in the last three years.