05000423/LER-2012-001, Regarding Main Steam Line Pressure Transmitters Declared Inoperable

From kanterella
(Redirected from 05000423/LER-2012-001)
Jump to navigation Jump to search
Regarding Main Steam Line Pressure Transmitters Declared Inoperable
ML12107A027
Person / Time
Site: Millstone Dominion icon.png
Issue date: 04/03/2012
From: Adams W
Dominion, Dominion Nuclear Connecticut
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
12-204 LER 12-001-00
Download: ML12107A027 (6)


LER-2012-001, Regarding Main Steam Line Pressure Transmitters Declared Inoperable
Event date:
Report date:
Reporting criterion: 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications

10 CFR 50.73(a)(2)(v), Loss of Safety Function

10 CFR 50.73(a)(2)(i)

10 CFR 50.73(a)(2)(vii), Common Cause Inoperability

10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded

10 CFR 50.73(a)(2)(viii)(A)

10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition

10 CFR 50.73(a)(2)(viii)(B)

10 CFR 50.73(a)(2)(iii)

10 CFR 50.73(a)(2)(ix)(A)

10 CFR 50.73(a)(2)(iv)(A), System Actuation

10 CFR 50.73(a)(2)(x)

10 CFR 50.73(a)(2)(v)(A), Loss of Safety Function - Shutdown the Reactor

10 CFR 50.73(a)(2)(v)(B), Loss of Safety Function - Remove Residual Heat

10 CFR 50.73(a)(2)(i)(A), Completion of TS Shutdown
LER closed by
IR 05000245/2012003 (23 July 2012)
4232012001R00 - NRC Website

text

Dominion Dominion Nuclear Connecticut, Inc.

Millstone Power Station Rope Ferry Road Waterfoid, CT 06385

. APR 0 3 2012 U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555 Serial No.

MPS Lic/LES Docket No.

License No.12-204 RO 50-423 NPF-49 DOMINION NUCLEAR CONNECTICUT, INC.

MILLSTONE POWER STATION UNIT 3 LICENSEE EVENT REPORT 2012-001-00 MAIN STEAM LINE PRESSURE TRANSMITTERS DECLARED INOPERABLE This letter forwards Licensee Event Report (LER) 2012-001-00 documenting a condition discovered on February 9, 2012, where the surveillance procedure for performing maintenance on main steam pressure transmitters did not incorporate Environmental Qualification (EQ) Program requirements and resulted in an event or condition that could have prevented the fulfillment of the safety function of structures or systems that are needed to shutdown the reactor and mitigate the consequences of an accident, and a condition which was not in compliance with the plant's Technical Specifications at Millstone Power Station Unit 3. This LER is being submitted pursuant to 10 CFR 50.73(a)(2)(i)(B) and 10 CFR 50.73(a)(2)(v)(C).

If you have any questions or require additional information, please contact Mr. William D. Bartron at (860) 444-4301.

Sincerely, W. M. Adams Plant Manager - Millstone Attachments: 1 Commitments made in this letter: None

Serial No.12-204 Docket No. 50-423 Licensee Event Report 2012-001-00 Page 2 of 2 cc:

U.S. Nuclear Regulatory Commission Region I 475 Allendale Road King of Prussia, PA 19406-1415 C. J. Sanders Project Manager - Millstone Power Station U.S. Nuclear Regulatory Commission One White Flint North 11555 Rockville Pike Mail Stop 08B3 Rockville, MD 20852-2738 NRC Senior Resident Inspector Millstone Power Station

Serial No.12-204 Docket No. 50-423 Licensee Event Report 2012-001-00 ATTACHMENT LICENSEE EVENT REPORT 2012-001-00 MILLSTONE POWER STATION UNIT 3 DOMINION NUCLEAR CONNECTICUT, INC.

NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 10/31/2013 (10/2010)

, the NRC may not conduct or sponsor, digits/characters for each block) and a person is not required to respond to, the information collection.

3. PAGE Millstone Power Station - Unit 3 05000423 1OF3
4. TITLE Main Steam Line Pressure Transmitters Declared Inoperable
5. EVENT DATE
6. LER NUMBER
7. REPORT DATE
8. OTHER FACILITIES INVOLVED FACILITY NAME DOCKET NUMBER SEQUENTIAL REV MONTH DAY YEAR 05000 MONTH DAY YEAR YEAR INUMBER NO.IFALTYNMDOKTUBE FACILITY NAME DOCKET NUMBER 02 09 2012 2012-001 -00 04 03 2012 05000
11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR :(Check all that apply) 9.OPERATINGMODE 20.2201 (b) 20.2203(a)(3)(i) 50.73(a)(2)(i)(C) 50.73(a)(2)(vii) 20.2201(d) 20.2203(a)(3)(ii) 50.73(a)(2)(ii)(A) 50.73(a)(2)(viii)(A) 20.2203(a)(1) 20.2203(a)(4) 50.73(a)(2)(ii)(B) 50.73(a)(2)(viii)(B) 20.2203(a)(2)(i) 50.36(c)(1 )(i)(A) 50.73(a)(2)(iii) 50.73(a)(2)(ix)(A) 20.2203(a)(2)(ii) 50.36(c)(1)(ii)(A) 50.73(a)(2)(iv)(A) 50.73(a)(2)(x)
10. POWER LEVEL 20.2203(a)(2)(iii) 50.36(c)(2) 50.73(a)(2)(v)(A) 73.71 (a)(4) 20.2203(a)(2)(iv) 50.46(a)(3)(ii) 50.73(a)(2)(v)(B) 73.71 (a)(5) 100 20.2203(a)(2)(v) 50.73(a)(2)(i)(A)

X 50.73(a)(2)(v)(C)

OTHER 20.2203(a)(2)(vi)

X 50.73(a)(2)(i)(B) 50.73(a)(2)(v)(D)

Specify in Abstract below or in

1.

EVENT DESCRIPTION

On February 9, 2012, at 1655, while operating in MODE 1 at 100% power, Millstone Power Station Unit 3 (MPS3) discovered that all twelve main steam [AB] line pressure transmitter's (MSPT) Litton-Veam connectors had not been reconnected using new gaskets as required by Equipment Qualification (EQ)

Record EQR 120-8-1 after maintenance was performed between January 17, 2012, and February 2, 2012. Upon discovery, operators declared the main steam line transmitters inoperable. This caused both channels of main steam line isolation (MSLI) to be declared inoperable. Technical Specification (TS) 3.3:2, Engineered Safety Features Actuation System Instrumentation, requires restoration of at least one channel of MSLI within 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />, or be in hot standby within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />, but does not specify actions to be taken when two channels are inoperable. Therefore, operators entered into TS Action Statement (TSAS) 3.0.3. By 2151 on February 9, 2012, new gaskets were installed in all twelve main steam line pressure transmitters, operators declared the transmitters operable, and exited MPS3 TSAS 3.0.3.

Because the actions were completed within the TS Action Statement, a plant downpower was not required. A loss of safety function for post accident monitoring purposes has been presumed because the EQ tests performed for the components in question did not mechanically cycle the Litton-Veam connectors. Therefore, by reusing the gasket, which has been mechanically cycled, the connector is no longer in the tested condition and is not considered qualified. The MSPTs also provide a post accident monitoring function per TS 3.3.3.6, Accident Monitoring Instrumentation. TS 3.3.3.6 requires that 2 channels of instrumentation must be restored within 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />, or the unit must be placed in hot standby within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and hot shutdown within the following 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />. Since the condition was not recognized earlier, this also resulted in a condition prohibited by Technical Specifications (TS).

This condition is being reported pursuant to 10 CFR 50.73(a)(2)(v)(C) as an event or condition that could have prevented the fulfillment of the safety function of structures or systems that are needed to shutdown the reactor and mitigate the consequences of an accident. This condition is also reportable as a condition prohibited by the plant's Technical Specifications pursuant to 10 CFR 50.73(a)(2)(i)(B).

2.

CAUSE

The cause of this condition was determined to be a failure to incorporate 1998 EQ program requirement changes into the affected surveillance procedures as required by station administrative procedures.

3.

ASSESSMENT OF SAFETY CONSEQUENCES

The main steam line steam generator (SG) [SG] pressure transmitters provide input to the MSLI signal that closes the fast acting main steam isolation valves (MSIVs) [V] located on each main steam line downstream of the four SGs. Sustained uncontrolled steam release from more than one SG is prevented following a postulated steam system piping failure (SLB) by the automatic trip of the MSIVs.

For a SLB inside containment, MSLI is activated by either high containment pressure or low steam line pressure, or manual operator action from the control room. For a SLB outside containment, manual operator action from the control room would be taken to isolate the SG if the SG pressure transmitters failed to automatically provide inputs for MSLI.

A loss of safety function for post accident monitoring of steam generator pressures has been presumed because the EQ tests performed for the components in question assumed the Litton-Veam connector seals are replaced each time after demating. There is a reasonable expectation that the MSPTs would have functioned to isolate the MSIVs on a steam line break in the main steam valve building.

Accordingly, it can reasonably be assured that the MSPTs would have functioned to support identifying and isolating a faulted steam generator due to either a steam line break or a feed line break in the main steam valve building. It cannot be assured that MSPTs would have provided their post accident I

monitoring function for the required mission time, i.e., 30 days; however, there are alternate indications which could have been used, including SG level, auxiliary feedwater flow and reactor coolant system temperature.

4.

CORRECTIVE ACTION

New EQ gaskets were installed in all twelve main steam line pressure transmitters upon discovery. Also, Surveillance Procedure SP3444-BO1 has been revised to incorporate a step to require changing out gaskets during future surveillance or maintenance evolutions. A review of similar surveillance procedures for MPS3 was performed, and no similar situations were found. Additional corrective actions are being taken in accordance with the station's corrective action program.

5.

PREVIOUS OCCURRENCES

No previous similar events/conditions were identified.

Energy Industry Identification System (EIIS) codes are identified in the text as [XX].

1