05000440/LER-2010-002, Regarding Piping Leak Results in Condition Prohibited by Technical Specifications
| ML101120653 | |
| Person / Time | |
|---|---|
| Site: | Perry  |
| Issue date: | 04/16/2010 |
| From: | Bezilla M FirstEnergy Nuclear Operating Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| L-10-101 LER 10-002-00 | |
| Download: ML101120653 (6) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(i) 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(ii) 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) |
| 4402010002R00 - NRC Website | |
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FENOC FirstEnergy Nuclear Operating Company Perry Nuclear Power Station 10 Center Road Perry, Ohio 44081 Mark B. Bezilla Vice President 440-280-5382 Fax: 440-280-8029 April 16, 2010 L-10-101 10 CFR 50.73(a)(2)(i)(B)
ATTN: DocumentControl Desk U. S. Nuclear Regulatory Commission Washington, DC 20555-0001
SUBJECT:
Perry Nuclear Power Plant Docket No. 50-440, License No. NPF-58 Licensee Event Report Submittal Enclosed is Licensee Event Report (LER) 2010-002, "Piping Leak Results in Condition Prohibited by Technical Specifications." 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.
Sincerely,
Enclosure:
LER 2010-002 cc:
NRC Project Manager NRC Resident Inspector NRC Region III
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB NO. 3150-0104 EXPIRES 8/31/2010 (9-2007)
, the NRC may (See reverse for required number of not conduct or sponsor, and a person is not required to respond to, the digits/characters for each block) information collection.
- 3. PAGE Perry Nuclear Power Plant 05000440 1 OF 5
- 4. TITLE Piping Leak Results in Condition Prohibited by Technical Specifications
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED SEQUENTIAL REV FACILITY NAME DOCKET NUMBER MONTH DAY YEAR YEAR NUMBER NO.
MONTH DAY YEAR S21 00
- - 00211FACILITY NAME DOCKET NUMBER 02 16 2010 2010 -002
- - 00 04 16 2010
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply)
El 20.2201(b)
[] 20.2203(a)(3)(i)
El 50.73(a)(2)(i)(C) 0 50.73(a)(2)(vii)
E] 20.2201(d)
E] 20.2203(a)(3)(ii)
[j 50.73(a)(2)(ii)(a)
E] 50.73(a)(2)(viii)(A)
[] 20.2203(a)(1)
E] 20.2203(a)(4)
E] 50.73(a)(2)(ii)(B)
[] 50.73(a)(2)(viii)(B)
E: 20.2203(a)(2)(i)
El 50.36(c)(1)(i)(A)
El 50.73(a)(2)(iii)
El 50.73(a)(2)(ix)(A)
- 10. POWER LEVEL El 20.2203(a)(2)(ii)
El 50.36(c)(1)(ii)(A)
Ej 50.73(a)(2)(iv)(A) 17 50.73(a)(2)(x)
[] 20.2203(a)(2)(iii)
[] 50.36(c)(2)
E] 50.73(a)(2)(v)(A)
[1 73.71 (a)(4) 100 E] 20.2203(a)(2)(iv)
El 50.46(a)(3)(ii)
[] 50.73(a)(2)(v)(B)
El 73.71(a)(5)
E] 20.2203(a)(2)(v)
EL 50.73(a)(2)(i)(A)
L] 50.73(a)(2)(v)(C)
El OTHER Specify in Abstract below 20.2203(a)(2)(vi)
~
50.73(a)(2)(i)(B) 50.73(a)(2)(V)(D) or in Condition A (i.e., one ECCW subsystem inoperable). TS LCO 3.7.10, Required Action A.1 was performed to immediately declare associated systems and components inoperable. The equipment declared inoperable included the following:
Residual Heat Removal (RHR) [BO] subsystems B and C in Low Pressure Coolant Injection mode (TS LCO 3.5.1)
RHR Containment Spray [BO] subsystem B (TS LCO 3.6.1.7)
RHR Suppression Pool Cooling [BO] subsystem B (TS LCO 3.6.2.3)
Combustible Gas Mixing [BB] subsystem B (TS LCO 3.6.3.3)
Control Room HVAC subsystem B (TS LCO 3.7.4 previously inoperable to support isolation and repair activities).
The leak was isolated in accordance with plant procedures and at 1415 hours0.0164 days <br />0.393 hours <br />0.00234 weeks <br />5.384075e-4 months <br />, TS LCO 3.7.10 CONDITION A was exited when the ECCW B was declared operable. Additionally, TS LCOs 3.5.1, 3.6.1.7, 3.6.2.3, and 3.6.3.3 were exited.
The associated ECCW B instrument piping was replaced and the leak repaired. On February 18, 2010, at 0457 hours0.00529 days <br />0.127 hours <br />7.556217e-4 weeks <br />1.738885e-4 months <br />, TS LCO 3.7.4 was exited when Control Room HVAC subsystem B was declared operable.
CAUSE OF EVENT
The cause of the operation prohibited by TS was that guidance for evaluating the operability impact of flaws in ASME piping was not adequately captured in plant procedures or training. The POD process does not consider reportability ramifications when assigning a completion time.
Consequently, the Shift Manager assigned a completion time without considering the impact if the POD could not support system operability.
For the leak itself, fatigue cracking was identified as the primary failure mechanism. After the crack developed a corrosion component was also involved. During the causal investigation, it was identified that a missing tubing support (i.e., Stauff clamp) downstream of the cracked weld was identified and corrected in 2006. This support piece was most likely missing since plant construction exposing the section of pipe to years of high-cycle, low stress fatigue.
EVENT ANALYSIS
The ECCW system provides a heat sink for the removal of process and operating heat from safety-related components during a design basis accident or transient. The ECCW system consists of two independent and redundant closed loop subsystems (A and B). Each subsystem consists of a motor driven pump, heat exchanger, surge tank, and associated piping and valves. The ECCW heat exchangers transfer heat to the Emergency Service Water system. The isolation of ECCW to other components or systems may render those components or systems inoperable, but does not affect the operability of the ECCW system. During the period of ECCW B inoperability, (i.e., from February 15, 2010, at 2130 hours0.0247 days <br />0.592 hours <br />0.00352 weeks <br />8.10465e-4 months <br />, until February 16, 2010, at 1415 hours0.0164 days <br />0.393 hours <br />0.00234 weeks <br />5.384075e-4 months <br />), ECCWA and its associated supported systems were operable.
On February 15, 2010, at 2130 hours0.0247 days <br />0.592 hours <br />0.00352 weeks <br />8.10465e-4 months <br />, the plant entered TS LCO 3.7.10, Condition A (One ECCW subsystem inoperable) with a Required Action A. 1 to declare associated system(s) or component(s)
inoperable immediately. The subsystem B inoperability was not recognized, and so the plant entered TS LCO 3.7.10, Condition B (Required Action and Completion Time of Condition A not met) with Required Actions B.1, be in MODE 3 (Hot Shutdown) in 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />, and B.2, be in MODE 4 (Cold Shutdown) in 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />. On February 16, 2010, at 0930 hours0.0108 days <br />0.258 hours <br />0.00154 weeks <br />3.53865e-4 months <br />, TS LCO 3.7.10 Required Action B.1 Completion Time was not met, and a subsequent reportability review determined that this condition was prohibited by the plant's TS and reportable in accordance with 10 CFR 50.73(a)(2)(i)(B). TS LCO 3.7.10 Required Action A.1 was met on February 16, 2010, at 1310 hours0.0152 days <br />0.364 hours <br />0.00217 weeks <br />4.98455e-4 months <br />, 15 hours1.736111e-4 days <br />0.00417 hours <br />2.480159e-5 weeks <br />5.7075e-6 months <br /> and 40 minutes after the plant entered Condition A.
The completion times of the additional TS LCOs (i.e., for TS LCOs 3.5.1, 3.6.1.7, 3.6.2.3, 3.6.3.3, and 3.7.4) that were entered due to the ECCW B inoperability, were not challenged. TS LCO 3.5.1 Condition C (i.e., two Emergency Core Cooling System injection subsystems inoperable) has the most limiting Completion Time for Required Action C.1, to restore one injection subsystem to operable status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. TS LCO 3.7.4, for the Control Room HVAC subsystem B (that remained inoperable for the piping repair) Condition A (i.e., one subsystem inoperable) has a Completion Time for Required Action A.1 to restore the subsystem to operable status within 30 days. The actual inoperability time for Control Room HVAC subsystem B due to ECCW B inoperability was approximately two days, seven-and-a-half hours.
The Probabilistic Risk Assessment (PRA) evaluation determined this event to be administrative in nature as a result of noncompliance with TS requirements. The respective function was available.
On this basis, this issue is viewed to be negligible from the PRA perspective.
If a "bounding" evaluation were to be postulated to account for a condition of the piping structural integrity being "indeterminate" from an engineering perspective, and ECCW B was postulated to be unavailable from the time of the leak discovery to the time of isolation, an incremental Conditional Core Damage Probability (ICCDP) of 2.64E-8 was calculated. The results indicate that ICCDP is below 1.OE-6, which is below the guidance threshold for being risk significant. Based on the PRA assessment, this event is considered to be of low safety significance.
CORRECTIVE ACTIONS
The plant procedure for PODs will be revised to direct consideration of reportability ramifications when establishing POD completion times. Additionally, procedure guidance will be developed to address through-wall piping leaks. Training courses will also be revised and Operations and other support personnel trained to the lessons learned from this event. In the interim, written guidance has been provided to the operators.
PREVIOUS SIMILAR EVENTS
The corrective action program database was reviewed for previous similar events occurring in the past three years. LER 2008-002, "Inoperable Emergency Closed Cooling System Results in Condition Prohibited by Technical Specifications" documents that ECCW B was inoperable due to insufficient minimum flow for approximately 52 hours6.018519e-4 days <br />0.0144 hours <br />8.597884e-5 weeks <br />1.9786e-5 months <br /> prior to required actions being taken to declare the associated systems and components inoperable. Identified causes included inadequacies in system operation and clearance procedures. The procedure changes that were developed could not reasonably be expected to prevent the occurrence of this event.
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.PRINTED ON RECYCLED PAPERPRINTED ON RECYCLED PAPER