05000285/LER-2005-001, Re Unplanned Reactor Trip Due to a Feedwater Transient at Low Power During Plant Shutdown

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Re Unplanned Reactor Trip Due to a Feedwater Transient at Low Power During Plant Shutdown
ML051230141
Person / Time
Site: Fort Calhoun Omaha Public Power District icon.png
Issue date: 04/27/2005
From: Bannister D
Omaha Public Power District
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
LIC-05-0035 LER 05-001-00
Download: ML051230141 (6)


LER-2005-001, Re Unplanned Reactor Trip Due to a Feedwater Transient at Low Power During Plant Shutdown
Event date:
Report date:
Reporting criterion: 10 CFR 50.73(a)(2)(iv), System Actuation

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

10 CFR 50.73(a)(2)(vi)

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

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

10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications
2852005001R00 - NRC Website

text

Omaha Public PowerDistrict 444 South 16th Street AMall Omaha NE 68102-2247 April 27, 2005 LIC-05-O03 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Mail Station P1-137 Washington, DC 20555

Reference:

Docket No. 50-285 Licensee Event Report 2005-001 Revision 0 for the Fort Calhoun Station

Subject:

Please find attached Licensee Event Report 2005-001, Revision 0, dated April 27, 2005. This report is being submitted pursuant to 10 CFR 50.73(a)(2)(iv). If you should have any questions, please contact me.

Sincerely, D. J. Bannister Manager - Fort Calhoun Station DJB/EPM/epm Attachment c:

INPO Records Center 7::r"2, 4171 Einploynent wi'ith Equal Opportunity

NRC FORM 366 U.S. NUCLEAR REGULATORY COM APPROVED BY OMB: NO. 3150-0104 EXPIRES: 06/30/2007 Estimated burden per response to comply with this mandatory collection request 50 hours5.787037e-4 days <br />0.0139 hours <br />8.267196e-5 weeks <br />1.9025e-5 months <br />.

Reported lessons learned are incorporated into the licensing process and fed back to Industry.

Send comments regarding burden estimate to the Records and FOIA/Privacy Service Branch (T-5 F52), U.S. Nuclear Regulatory Commission. Washington, DC 205554001 or by Internet e-mail LICENSEE EVENT REPORT (LER) to infocollectsenrc.gov, and to the Desk Officer, Office of Information and RegulatoryAffairs, NEOB-10202, (3150-0104), Office of Management and Budget. Washington, DC 20503. If a means used to impose an information collection does not display a currently valid OMB control (See reverse for required number of number, the NRC may not conduct or sponsor, and a person is not required to respond to. the digits/characters for each block)

3. PAGE Fort Calhoun Station 05000285 1 OF 5
4. TITLE Unplanned Reactor Trip Due to a Feedwater Transient at Low Power During Plant Shutdown
5. EVENT DATE
6. LER NUMBER
7. REPORT DATE
8. OTHER FACILITIES INVOLVED SEUNILRVFACILITY NAME DOCKET NUMBER MONTH DAY YEAR YEAR SENUMBER N

NO.

MONTH DAY YEAR 05000 FACILITY NAME DOCKET NUMBER 02 26 2005 2005 - 001 -

00 04 27 2005 05000

9. OPERATING 11.THIS REPORTIS SUBMITTED PURSUANTTO THE REQUIREMENTS OF 10 CFR§: (Checkallthatapply)

MODE o 20.2201(b) -

a

.20.2203(a)(3)(i).

.- O.50.73(a)(2)(i)(C) 50.73(a)(2)(vi) -'--

o 20.2201(d) a 20.2203(a)(3)(ii) 0 50.73(a)(2)(ii)(A) 0 50.73(a)(2)(viii)(A) 1I 20.2203(a)(1) 0 20.2203(a)(4) 0 50.73(a)(2)(ii)(B)

D 50.73(a)(2)(viii)(B) 0o 20.2203(a)(2)(i) 0 50.36(c)(1)(i)(A) 0 50.73(a)(2)(iii) 0 50.73(a)(2)(ix)(A)

10. POWER LEVEL 0 20.2203(a)(2)(ii) 0 50.36(c)(1)(ii)(A) 0 50.73(a)(2)(iv)(A) 0 50.73(a)(2)(x)

Ol 20.2203(a)(2)(iii) 0 50.36(c)(2) 0 50.73(a)(2)(v)(A) 0 73.71(a)(4)

O 20.2203(a)(2)(iv) 0 50.46(a)(3)(ii) 0 50.73(a)(2)(v)(B) 0 73.71(a)(5) 15 E 20.2203(a)(2)(v) 0 50.73(a)(2)(i)(A) 0 50.73(a)(2)(v)(C) 0 OTHER O 20.2203(a)(2)(vi) 0 50.73(a)(2)(i)(B) 0 50.73(a)(2)(v)(D)

Specify in Abstract below or in (If more space is required, use additional copies of (If more space is required, use additional copies of (If more space is required, use additional copies of NRC Form 366A) (17)

In addition four contributing causes were identified in the course of the analysis:

1.

SG level and pressure control procedures did not provide adequate guidance for low power operation.

2.

SG feedwater flow indication is inadequate for low power operation

3.

Insufficient supervisory oversight regarding activities involving operators with limited experience during low power operation.

There is a minimal amount of recurring low power operation training leading to over reliance on the limited amount of individual operating experience in controlling certain processes at low power operations.

The analysis determined that there was not a failure of the feedwater or steam dump and bypass valve control systems.

SAFETY SIGNIFICANCE

The Loss of Load trip is not significant to nuclear safety because this type of trip is an analyzed event. Although the trip challenges plant equipment, all structures, systems and components (SSCs) responded appropriately, and the trip was uncomplicated.

In addition, the relatively low power level of the reactor (-12%) prior to the trip contributes to the assertion that the event was non-safety significant due to the minimal increase in core damage risk. No reactor safety functions were challenged during the event. Therefore, this event had no impact on the health and safety of the public.

CORRECTIVE ACTIONS

Immediate Corrective Actions The plant shutdown was completed as required by plant procedures and EOP-00 was exited. The SG levels were restored to the normal band.

Long Term Corrective Actions to Correct the Root Cause Provide enhanced low power procedure guidance for operators on steam dump/bypass valves and feedwater bypass valves control. This will be completed by Julyj, 2005.__

Revise OPD4-19, "Reactivity Management," and other procedures as necessary to ensure that there are clear expectations for monitoring reactivity manipulations. This will be completed by July 1, 2005.

Additional actions to correct the contributing causes will be tracked by the FCS corrective action program.

SAFETY SYSTEM FUNCTIONAL FAILURE This event did not result in a safety system functional failure in accordance with NEI-99-02.

PREVIOUS SIMILAR EVENTS

LERs 2003-003 and 1996-007 documented low power reactor trips.