05000285/LER-2007-004, Re Inadvertent Isolation of All Containment Spray Due to an Inadequate Test Procedure
| ML071700086 | |
| Person / Time | |
|---|---|
| Site: | Fort Calhoun  |
| Issue date: | 06/11/2007 |
| From: | Bannister D Omaha Public Power District |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| LIC-07-0045 LER 07-004-00 | |
| Download: ML071700086 (7) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(i) 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)(i)(B), Prohibited by Technical Specifications |
| 2852007004R00 - NRC Website | |
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Omaha Public Power District 444 South 16th Street Mall Omaha NE 68102-2247 LIC-07-0045 June 11, 2007 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Mail Station P1-137 Washington, DC 20555
Reference:
Subject:
Docket No. 50-285 Licensee Event Report 2007-004 Revision 0 for the Fort Calhoun Station Please find attached Licensee Event Report 2007-004, Revision 0, dated June 11, 2007. This report is being submitted pursuant to 50.73(a)(2)(v)(D) and 10 CFR 50.73(a)(2)(vii). If you should have any questions, please contact me.
Sincerely, D. J. Bannister Manager - Fort Calhoun Station DJB/epm Attachment c:
B. S. Mallett, NRC Regional Administrator, Region IV Alan Wang, NRC Project Manager J. D. Hanna, NRC Senior Resident Inspector INPO Records Center jL~e&A Employment with Equal Opportunity I ý-ý ýý C-1 w 2
NRC FORM 366 U.S. NUCLEAR REGULATORY COMI APPROVED BY OMB: NO. 3150-0104 EXPIRES: 06/30/2007 (6-2004)
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 20555-0001, or by internet e-mail LICENSEE EVENT REPORT (LER) to infocollects@nrc.gov, and to the Desk Officer, Office of Information and Regulatory Affairs, 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 number, the NRC may not conduct or sponsor, and a person is not required to respond to, the (See reverse for required number of information collection.
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- 3. PAGE Fort Calhoun Station 05000285 1 OF 6.
- 4. TITLE Inadvertent Isolation of All Containment Spray Due to an Inadequate Test Procedure
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED MONTH DAY YEAR SEQUENTIAL REV FACILITY NAME DOCKET NUMBER NUMBER NO.
05000 FACILITY NAME DOCKET NUMBER 04 12 2007 2007 004 -
00 06 11 2007 05000
- 9. OPERATING
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR§: (Check all that apply)
MODE El 20.2201(b)
El 20.2203(a)(3)(i)
El 50.73(a)(2)(i)(C) 0 50.73(a)(2)(vii)
I]
20.2201(d)
[] 20.2203(a)(3)(ii)
El 50.73(a)(2)(ii)(A)
E-50.73(a)(2)(viii)(A) 1 El 20.2203(a)(1)
El 20.2203(a)(4)
El 50.73(a)(2)(ii)(B)
[I 50.73(a)(2)(viii)(B)
[I 20.2203(a)(2)(i)
El 50.36(c)(1)(i)(A)
El 50.73(a)(2)(iii)
[E 50.73(a)(2)(ix)(A)
- 10. POWER LEVEL [] 20.2203(a)(2)(ii)
I]
50.36(c)(1)(ii)(A)
El 50.73(a)(2)(iv)(A)
El 50.73(a)(2)(x)
El 20.2203(a)(2)(iii)
El 50.36(c)(2)
[] 50.73(a)(2)(v)(A)
El 73.71(a)(4)
El 20.2203(a)(2)(iv)
[] 50.46(a)(3)(ii)
El 50.73(a)(2)(v)(B)
El 73.71(a)(5) 100 El 20.2203(a)(2)(v)
El 50.73(a)(2)(i)(A)
[] 50.73(a)(2)(v)(C)
El OTHER [I 20.2203(a)(2)(vi)
El 50.73(a)(2)(i)(B)
Z 50.73(a)(2)(v)(D)
Specify in Abstract below or in (If more space is required, use additional copies of NI-C, (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)
A contributing cause was reliance on adequacy of existing design. EC27582 was duplicating an existing interlock from MR-FC-90-053. Because of this, it appears that less scrutiny (questioning of design) than normal was applied during the design phase of the modification.
CORRECTIVE ACTIONS
As immediate corrective action, OP-ST-ESF-0009 and 0010 were revised to eliminate the problem.
In addition, the following corrective actions will be taken:
- 1. Revise appropriate design procedures to specifically prompt design engineers of configuration changes affecting complex systems, or systems with more than one train, (e.g. engineered safeguards system) to consider the system response to a DBA occurring during surveillance testing and ensure the system remains operable. This will be completed by August 31, 2007.
- 2. Identify other safeguards systems that may have cross-train interlocks and review surveillance tests on the CS and the systems identified to verify that the minimum requirements for operability are maintained during surveillance testing. This will be completed by September 30, 2007.
Other actions related to this issue will be controlled by the stations corrective action system.
SAFETY SIGNIFICANCE
The CS system would not have been capable of automatically responding to a CSAS only if a DBA occurred concurrent with either a loss of offsite power or failure of the containment spray pump breaker to close during the surveillance testing. Plant operators, in accordance with their training, would have terminated surveillance testing and entered the standard post-trip actions Emergency Operating Procedure, EOP-00, and manually returned the closed valve and the emergency diesel generator to normal mode which would have enabled CS flow. Potentially adverse consequences would be minimized by the EOPs and associated operator training in place. The containment heat removal capability of the containment air recirculation and cooling system, which is an independent safeguards system available for a loss of coolant accident (LOCA), further reduces the safety significance of the temporarily disabled spray flow condition.
The surveillance tests are performed at a quarterly frequency. The CS system was unavailable for about 2.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> during the performance of each test. The likelihood of an accident with either a loss of offsite power or failure of the containment spray pump breaker to close during the surveillance test is very low. Therefore, the effect to the public would have been minimal.
SAFETY SYSTEM FUNCTIONAL FAILURE This event does result in a safety system functional failure in accordance with NEI-99-02.
PREVIOUS SIMILAR EVENTS
There have not been any events in the last three years resulting from inadequate design affecting system operability during surveillance testing.