05000440/LER-2018-002, Failed Fuse Leads to Loss of Safety Function
| ML18236A294 | |
| Person / Time | |
|---|---|
| Site: | Perry  |
| Issue date: | 08/23/2018 |
| From: | Hamilton D FirstEnergy Nuclear Operating Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| L-18-192 LER 2018-002-00 | |
| Download: ML18236A294 (6) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(iii) 10 CFR 50.73(a)(2)(x) 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability |
| 4402018002R00 - NRC Website | |
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FirstEnergy Nuclear Operating Company David B. Hamilton Vice President August 23, 2018 L-18-192 ATTN: Document Control 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 Perry Nuclear Power Plant PO Box 97 10 Center Road Perry. Ohio 44081 440-280-5382 1 OCFR50.73(a)(2)(v)(D)
Enclosed is Licensee Event Report (LER) 2018-002, "Failed Fuse Leads to Loss of Safety Function". There are no regulatory commitments contained in this submittal.
If there are any questions or if additional information is required, please contact Mr. Nicola Conicella, Manager - Regulatory Compliance, at (440) 280-5415.
Sincerely, David B. Hamilton Vice President
Enclosure:
LER 2018-002 cc:
NRC Project Manager NRC Resident Inspector NRC Region Ill Regional Administrator
Enclosure L-18-192 LER 2018-002
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY 0MB: NO. 3150-0104 EXPIRES: 3/31/2020 (04-2018)
, the NRC may not conduct or sponsor, and a person is not required to respond to, the infonmation collection.
- 3. Page Perry Nuclear Power Plant 05000-440 1 OF 4
- 4. Title:
Failed Fuse Leads to Loss of Safety Function
- 5. Event Date
- 6. LER Number
- 7. Report Date
- 8. Other Facilities Involved I
Sequential I Rev Facility Name Docket Number Month Day Year Year Number No.
Month Day Year 05000 Facility Name Docket Number 07 01 2018 2018 -
002 00 08 23 2018 05000
- 9. Operating Mode
- 11. This Report is Submitted Pursuant to the Requirements of 10 CFR §: (Check all that apply)
D 20.2201(b)
D 20.2203(a)(3)(i)
D 50. 73(a)(2)(ii)(A)
D 50. 73(a)(2)(viii)(A) 1 D 20.2201(d)
D 20.2203(a)(3)(ii)
D 50. 73(a)(2)(ii)(B)
D 50. 73(a)(2)(viii)(B)
D 20.2203(a)(1)
D 20.2203(a)(4)
D 50.73(a)(2)(iii)
D 50. 73(a)(2)(ix)(A)
D 20.2203(a)(2)(i)
D 50.36(c)(1 )(i)(A)
D 50. 73(a)(2)(iv)(A)
D 50.73(a)(2)(x)
- 10. Power Level D 20.2203(a)(2)(ii)
D 50.36(c)(1 )(ii)(A)
D 50. 73(a)(2)(v)(A)
D 73.71 (a)(4)
D 20.2203(a)(2)(iii)
D 50.36(c)(2)
D 50. 73(a)(2)(v)(B)
D 73.71(a)(5)
D 20.2203(a)(2)(iv)
D 50.46(a)(3)(ii)
D 50. 73(a)(2)(v)(C)
D 73. 77(a)(1) 100 D 20.2203(a)(2)(v)
D 50. 73(a)(2)(i)(A)
~ 50. 73(a)(2)(v)(D)
D 73.77(a)(2)(i)
D 20.2203(a)(2)(vi)
D 50. 73(a)(2)(i)(B)
D 50.73(a)(2)(vii)
D 73.77(a)(2)(ii)
D 50. 73(a)(2)(i)(C)
~ Other (Specify in Abstract below or in 002 TS 3.3. 7.1 "Control Room Emergency Recirculation (CRER) System Instrumentation" conditions A and B for the inability to automatically initiate Division 1 CRER.
TS 3.7.10 "Emergency Closed Cooling Water (ECCW) System" condition A for the inability to automatically initiate the "A" train of ECC.
TS 3.5.1 "ECCS-Operating" conditions A and C for the inoperability of LPCS and RHR A TS 3.5.3 "Reactor Core Isolation Cooling (RCIC) System" condition A for the inoperability of RCIC TS 3.6.1. 7 "Residual Heat Removal (RHR) Containment Spray System" condition A for the inoperability of RHR A TS 3.6.2.3 "Residual Heat Removal (RHR) Suppression Pool Cooling System" condition A for the inoperability of RHR A TS 3.6.3.3 "Combustible Gas Mixing System" condition A for the inoperability of the "A" train of Combustible Gas Mixing.
TS 3.7.4 "Control Room Heating. Ventilating. and Air Conditioning (HVAC) System" condition A for the inoperability of the A train of Control Room HVAC.
TS 3.3.8.1 "Loss of Power (LOP) Instrumentation" condition A for the inoperability of Division 1 LOP instrumentation.
On July 1, 2018, at 0230 hours0.00266 days <br />0.0639 hours <br />3.80291e-4 weeks <br />8.7515e-5 months <br />, the fuse was replaced and the Division 1 ECCS LOCA initiation logic and associated systems were declared operable. On July 1, 2018, at 0824 hours0.00954 days <br />0.229 hours <br />0.00136 weeks <br />3.13532e-4 months <br />, Event Notification#53481 was made to the Nuclear Regulatory Commission's Operations Center under 10 CFR 50.72(b)(3)(v)(D).
CAUSE
The removed Gould Shawmut TR30R fuse was quarantined and sent to a laboratory for failure analysis.
Failure analysis concluded that the cause of the fuse failure was a manufacturing defect. There was no evidence that the fuse had ever been subjected to a current level that exceeded its current rating. The short circuit element had physically pulled away from the overload element, indicating that the fuse elements were under tension at the time of separation. This tension was likely placed on the fuse element during manufacturing when the two ferrules were crimped onto the fuse barrel. The crimping operation caused one of the ferrules to move outward from the fuse barrel.
EVENT ANALYSIS
A Probabilistic Risk Assessment (PRA) evaluation was performed. The assessment concluded that the June 30, 2018, fuse failure resulted in a very small change to overall plant risk. The corresponding change in Core Damage Frequency (CDF) (delta CDF=1.0E-09/year) and corresponding change in Large Early Release Frequency (LERF) (delta LERF = 1.6E-10/year) are below the thresholds of 1.0E-06/year delta CDF and REV NO.
00 YEAR 2018 SEQUENTIAL NUMBER 002 1.0E-07/year delta LERF as discussed in Regulatory Guide 1.174. Based on these results, the risk of this event is very small in accordance with the Regulatory Guide.
CORRECTIVE ACTIONS
Immediate corrective actions replaced the failed fuse. The spare fuse inventory was inspected to remove the manufacturing lot of suspect fuses. Inspections are being performed for susceptible circuits that could have the suspect fuses. If a suspect fuse is found, it will be replaced.
PREVIOUS SIMILAR EVENTS
REV NO.
00 On February 11, 2016, at approximately 1505 hours0.0174 days <br />0.418 hours <br />0.00249 weeks <br />5.726525e-4 months <br /> with the plant in mode 4, an indicated loss of power to the Division 1 4160 volt bus, EH 11, occurred. An invalid undervoltage signal tripped the bus supply breaker, and the bus loads shed, as expected. The Division 1 diesel generator (DG) started and loaded the EH11 bus.
Subsequently the Division 1 DG was manually shutdown due to cooling water not being available. This de-energized all Division 1 equipment, including the train supplying shutdown cooling at the time.
A Ferraz Shawmut OT-15 fuse was found to exhibit intermittent continuity. Failure analysis and simple troubleshooting methods determined the cause of the loss of the Division 1 bus, EH11, was due to an invalid undervoltage signal caused by the failure of the fuse which supplies the undervoltage and degraded voltage protection circuitry. The failure analysis revealed that the fuse internals were not soldered correctly during the manufacturing process. One of the fuse elements to fuse ferrule connections had flux applied but no solder.
A 10 CFR Part 21 report was filed by the supplier on March 22, 2016. This event was reported under
- 50. 73(a)(2)(iv)(A) as an invalid actuation and 50. 73(a)(2)(i)(B) for an operation or condition prohibited by technical specifications.
COMMITMENTS
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