05000440/LER-2011-004, Regarding Flooding Calculation Deficiency Results in Unanalyzed Condition
| ML12018A337 | |
| Person / Time | |
|---|---|
| Site: | Perry  |
| Issue date: | 01/16/2012 |
| From: | Kaminskas V FirstEnergy Nuclear Operating Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| L-12-019 LER 11-004-00 | |
| Download: ML12018A337 (5) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition 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)(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 |
| 4402011004R00 - NRC Website | |
text
FENOCT FirstEnergy Nuclear Operating Company Perry Nuclear Power Plant 10 Center Road Perry Ohio 44081 Vito A. Karninskas Vice President 440-280-5382 Fax: 440-280-8029 January 16, 2012 L-12-019 10 CFR 50.73(a)(2)(ii)(B)
ATTN: Document Control Desk U. S. Nuclear Regulatory Commission Washington, DC 20555-0001
SUBJECT:
Perry Nuclear Power Plant, Unit 1 Docket No. 50-440, License No. NPF-58 Licensee Event Report Submittal Enclosed is Licensee Event Report (LER) 2011-004, Flooding Calculation Deficiency Results in Unanalyzed Condition. There are no regulatory commitments contained in this submittal.
If there are any questions or if additional information is required, please contact Mr. Robert Coad, Manager - Regulatory Compliance, at (440) 280-5328.
Sini
Enclosure:
LER 2011-004 cc:
NRC Project Manager NRC Resident Inspector NRC Region III NFtf~
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB NO. 3150-0104 EXPIRES 10/31/2013 (10-2010)
, the NRC may digits/characters for each block) not conduct or sponsor, and a person is not required to respond to, the information collection.
- 3. PAGE Perry Nuclear Power Plant, Unit 1 05000-440 1 OF 4
- 4. TITLE Flooding Calculation Deficiency Results in Unanalyzed Condition
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED MINT SEQUENTIAL REV FACILIT NAME DOCKET NUMBE MONTH DAY YEAR YEAR NUMBER NO MONTH DAY YEAR 05000 11 16 2011 2011
- - 004 R 0T 01 16 2012 FACILITYNAME DOCKET NUMBER
- 9. OPERATING MODE!
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check'all that apply)
El 20.2201 (b)
D] 20.2203(a)(3)(i)
El 50.73(a)(2)(i)(C)
E] 50.73(a)(2)(vii) 1 20.2201(d)
[
20.2203(a)(3)(ii)
[] 50.73(a)(2)(ii)(A)
[] 50.73(a)(2)(viii)(A)
C 20.2203(a)(1)
[
20.2203(a)(4)
Z 50.73(a)(2)(ii)(B)
El 50.73(a)(2)(viii)(B)
El 20.2203(a)(2)(i)
E] 50.36(c)(1)(i)(A)
El 50.73(a)(2)(iii)
El 50.73(a)(2)(ix)(A)
- 10. POWER LEVEL
[
20.2203(a)(2)(ii)
E] 50.36(c)(1)(ii)(A)
[
50.73(a)(2)(iv)(A)
LI 50.73(a)(2)(x)
[]20,2203(a)(2)(iii)
[_1 50.36(c)(2)
[]50.73(a)(2)(v)(A)
[]73.71 (a)(4) 100
[ 20.2203(a)(2)(iv)
El 50.46(a)(3)(ii)
[: 50.73(a)(2)(v)(B)
LI 73.71 (a)(5)
[
20.2203(a)(2)(v)
[
50.73(a)(2)(i)(A)
E] 50.73(a)(2)(v)(C)
El OTHER Specify in Abstract below LI 20.2203(a)(2)(vi)
E] 50.73(a)(2)(i)(B)
[1 50.73(a)(2)(v)(D) or in On November 16, 2011, at 2000 hours0.0231 days <br />0.556 hours <br />0.00331 weeks <br />7.61e-4 months <br />, an immediate investigation of this issue was accepted by the control room. Per the immediate investigation, leakage would be detected as a sump alarm that would initiate a control room annunciator and operators would respond in accordance with Alarm Response Instruction (ARI) ARI-H13-P970-0001-F8, "Control Complex Laundry Sump Water Level Hi." The procedure had operators check for flooding and, if flooding exists, either stop the running pumps or isolate the leak. The calculation considers that the system is isolated from the crack at 30 minutes but does not specify actions needed to limit system drain down.
A strategy for flood mitigation was provided in the immediate investigation and was given to operators via Operations Night Order, "Control Complex Flooding Evaluation." The strategy included closure of specific valves depending on the location of the crack and opening specific vent valves to break siphon and limit drain down volume. The immediate investigation concluded that with all required operator actions being completed within 90 minutes from the start of the event, no safe shutdown equipment would be adversely affected.
On November 22, 2011, at 1957 hours0.0227 days <br />0.544 hours <br />0.00324 weeks <br />7.446385e-4 months <br />, a prompt functionality assessment was accepted by the control room. The assessment modified actions prescribed in the immediate investigation to increase efficiency. The modified actions included elimination of leakage into the Auxiliary Building by installation of a temporary flood barrier thereby eliminating the requirement to close valves to isolate the leak. On November 23, 2011, ARI-H 13-P970-0001-F8 was revised to incorporate the modified actions.
A Probabilistic Risk Assessment (PRA) evaluation was performed for the condition in which a postulated flooding event associated with the Control Complex Building lower elevation could have been improperly addressed. The difference between the mitigating strategies put into place as a result of this condition and the previous strategies documented in procedures indicates a delta Core Damage Frequency (CDF) of 7.86E-07. Based on the analysis, the event is below the threshold for being risk significant (increase in CDF is less than 1.OE-06), and is viewed as having low safety significance.
CORRECTIVE ACTIONS
Operations Night Order, "Control Complex Flooding Evaluation," was developed as an interim action until procedure changes were implemented.
A temporary flood barrier has been installed to minimize required operator actions.
ARI-H13-P970-0001-F8 has been revised to delineate actions described in the prompt functionality assessment which include securing pumps and opening vent valves to break siphon.
A modification will be prepared to install a permanent 18 inch high flood barrier in the Control Complex Building at door IB-1 03.
Calculations JL-083 and JL-061 (Auxiliary Building Flooding Analysis) will be reviewed to ensure that implicit operator actions are included to mitigate postulated internal flooding due to moderate energy line cracks. The calculations will be revised to include the specific actions (including timing of the actions) and interfaced with Operations to ensure that they can be performed. Operations will be formally tied into the revisions via a Design Interface Evaluation. The need to review calculation JL-061 was identified during the transportability review of the ongoing investigation.
A supplemental report will be submitted upon completion of the ongoing apparent cause evaluation.
PREVIOUS SIMILAR EVENTS
A review of Licensee Event Reports and the corrective action database for the past three years determined that two similar events had occurred.
LER 2009-002, "Diesel Generator C02 Fire Suppression Control Panel Miswiring Results in an Unanalyzed Condition," documented a condition where a wiring error resulted in inappropriate response of Division 2 and 3 diesel generator ventilation upon C02 actuation.
The corrective actions associated with this event focused on improved procedural guidance with respect to post maintenance/modification testing and the wire mark configuration control process.
These corrective actions would not have reasonably been expected to have prevented the event documented in LER 2011-004.
LER 2011-001, "Fire Protection Design Vulnerability Results in an Unanalyzed Condition," documented a legacy design issue that made the plant vulnerable to a hot short in the event of a postulated control room fire, which could result in a loss of the capability to safely shutdown the plant.
The corrective actions associated with this event focused on implementation of a permanent plant modification to isolate the affected circuits and review of other circuits for similar condition. These corrective actions would not have reasonably been expected to have prevented the event documented in LER 2011-004.
COMMITMENTS
There are no regulatory commitments contained in this report. Actions described in this document represent intended or planned actions, are described for the NRC's information, and are not regulatory
commitments