05000336/LER-2003-005, Regarding Loss of Shutdown Cooling During Refueling Outage

Regarding Loss of Shutdown Cooling During Refueling Outage

ML033360702
Person / Time
Site:	Millstone
Issue date:	11/21/2003
From:	Sarver S Dominion Nuclear Connecticut
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
B19010 LER 03-005-00
Download: ML033360702 (5)

LER-2003-005, Regarding Loss of Shutdown Cooling During Refueling Outage

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.73(a)(2)(x) 10 CFR 50.73(a)(2)(v)(A), Loss of Safety Function - Shutdown the Reactor
3362003005R00 - NRC Website

text

a" Dominionw Dominion Nuclear Connecticut, Inc.

Millstone Power Station Rope Ferry Road Waterford, CT' 06385 NOV 2 1 20 Docket No. 50-336 B19010 RE: 10 CFR 50.73(a)(2)(v)(B)

U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555 Millstone Power Station, Unit No. 2 Licensee Event Report 2003-005-00 Loss of Shutdown Cooling During Refueling Outage This letter forwards Licensee Event Report (LER) 2003-005-00, documenting an event that occurred at Millstone Unit No. 2, on October 14, 2003.

This LER is being submitted pursuant to 10 CFR 50.73(a)(2)(v)(B).

There are no regulatory commitments contained within this letter.

Should you have any questions regarding this submittal, Mr. David W. Dodson at (860) 447-1791, extension 2346.

please contact Very truly yours, DOMINION NUCLEAR CONNECTICUT, INC.

Director and Maintenance Attachment (1):

LER 2003-005-00 cc:

H. J. Miller, Region I Administrator R. B. Ennis, NRC Senior Project Manager, Millstone Unit No. 2 Millstone Senior Resident Inspector

C-1
99-

Docket No. 50-336 B19010 Millstone Power Station, Unit No. 2 LER 2003-005-00

NRC FORM 366 U.S. NUCLEAR REGULATORY APPROVED BY 0MB NO. 3150-0104 EXPIRES 7-31-2004 the NRC may not conduct or sponsor (See reverse for reaulred number of dioits/characters for each block) and a person Is not required to respond to the Information collection.

FACILITY NAME (1)

DOCKET NUMBER (2)

PAGE (3)

Millstone Power Station - Unit No. 2 05000336 1 OF 3

TITLE (4)

Loss of Shutdown Cooling as a Result of Switching Inverter Power Supplies EVENT DATE (5) l LER NUMBER (6)

REPORT DATE (7)

OTHER FACILITIES INVOLVED (8)

MO DAY YEAR YEAR SEQUENTIAL REV MO DAY YEAR FACILITY NAME DOCKET NUMBER INUMBER NO.

05000 10 14 2003 2003 -

005 -00 11 21 2003 FACILITY NAME DOCKET NUMBER

~~~~~~~~~~~~~05000 OPERATING 5

THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR 5: (Check all that apply) ( 1)

MODE (9) 20.2201(b) 20.2203(a)(3)(ii) 50.73(aX2)(iiXB) 50.73(a)(2Xix)(A)

POWER 0

20.2201(d) 20.2203(aX4) 50.73(aX2)(iii) 50.73(a)(2)(x)

LEVEL (101 20.2203(al1) 50.36(c1 )(iNA) 50.73(aV2)(iv)(A) 73.71 (aY4)

.^;_20.2203(a)(2)(i) 0.6c(i)A

=50.73(a)(2)(v)(A)

_73.71(a)(5) 20.2203(aX2Xii) 50.36(c)(2)

X 50.73(aX2Xv)(B)

OTHER 20.2203(aX2Xiii)

_ 50.46(aX3)(ii) 50.73(aX2Xv)(C)

Specdy In Abstract below or 20.2203(aX2Xiv) 50.73(aX2Xi)(A) 50.73(aX2){vXD)

In (if more space Is required, use additional copies of NRC Form 366A) (17) the event heat-up rate and core uncovery in this instance was estimated to occur 8.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> after boiling. This is considered to be sufficient time to both diagnose and mitigate the event. Also, the charging and high pressure safety injection systems were available to provide makeup to the RCS in the event of boiling. The overall safety significance of this event is considered to be low.

4. Corrective Action

The compensatory corrective action to ensure inverters are returned to Operations in a deenergized state has been implemented. This action allows the existing procedure to be performed as written with the intended result of successfully swapping power supplies for VA1 0.

The corrective actions to prevent recurrence are to modify the operations procedure, vendor manual, and associated training documents to reflect safe operation of the inverter and static switch.

A root cause investigation was performed and additional corrective actions are being addressed in accordance with the Millstone Corrective Action Program.

5. Previous Occurrences

No previous similar events were identified.

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