05000237/LER-2005-001, Regarding 4160 Volt Relaying and Metering Single Failure Vulnerability
| ML050940120 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 04/04/2005 |
| From: | Bost D Exelon Generation Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| SVPLTR: #05-0011 LER 05-001-00 | |
| Download: ML050940120 (5) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition 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)(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 |
| 2372005001R00 - NRC Website | |
text
10 CFR 50.73 April 4, 2005 SVPLTR: #05-0011 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Dresden Nuclear Power Station, Units 2 and 3 Renewed Facility Operating License Nos. DRP-19 and DPR-25 NRC Docket Nos. 50-237 and 50-249
Subject:
Licensee Event Report 237/2005-001, 4160 Volt Relaying and Metering Single Failure Vulnerability for Units 2 and 3.
Enclosed is Licensee Event Report 237/2005-001, 4160 Volt Relaying and Metering Single Failure Vulnerability for Units 2 and 3, for Dresden Nuclear Power Station. This event is being reported in accordance with 10 CFR 50.73(a)(2)(ii)(B), Any event or condition that resulted in the nuclear power plant being in an unanalyzed condition that significantly degraded plant safety, and 10 CFR 50.73(a)(2)(i)(B), Any operation or condition which was prohibited by the plants Technical Specifications.
Should you have any questions concerning this report, please contact Pedro Salas, Regulatory Assurance Manager, at (815) 416-2800.
Respectfully, Original Signed by Danny G. Bost Site Vice President Dresden Nuclear Power Station Enclosure cc:
Regional Administrator - NRC Region III NRC Senior Resident Inspector - Dresden Nuclear Power Station
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION (6-2004)
LICENSEE EVENT REPORT (LER)
(See reverse for required number of digits/characters for each block)
APPROVED BY OMB: NO. 3150-0104 EXPIRES: 06/30/2007
, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
- 1. FACILITY NAME Dresden Nuclear Power Station Unit 2
- 2. DOCKET NUMBER 05000237
- 3. PAGE 1 OF 4
- 4. TITLE 4160 Volt Relaying and Metering Single Failure Vulnerability for Units 2 and 3
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED MONTH DAY YEAR YEAR SEQUENTIAL NUMBER REV NO.
MONTH DAY YEAR FACILITY NAME Dresden Unit 3 DOCKET NUMBER 05000249 02 03 2005 2005 - 001 - 00 04 04 2005 FACILITY NAME N/A DOCKET NUMBER N/A
- 9. OPERATING MODE 1
- 10. POWER LEVEL 095
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR§: (Check all that apply) 20.2201(b) 20.2203(a)(3)(i) 50.73(a)(2)(i)(C) 50.73(a)(2)(vii) 20.2201(d) 20.2203(a)(3)(ii) 50.73(a)(2)(ii)(A) 50.73(a)(2)(viii)(A) 20.2203(a)(1) 20.2203(a)(4) 50.73(a)(2)(ii)(B) 50.73(a)(2)(viii)(B) 20.2203(a)(2)(i) 50.36(c)(1)(i)(A) 50.73(a)(2)(iii) 50.73(a)(2)(ix)(A) 20.2203(a)(2)(ii) 50.36(c)(1)(ii)(A) 50.73(a)(2)(iv)(A) 50.73(a)(2)(x) 20.2203(a)(2)(iii) 50.36(c)(2) 50.73(a)(2)(v)(A) 73.71(a)(4) 20.2203(a)(2)(iv) 50.46(a)(3)(ii) 50.73(a)(2)(v)(B) 73.71(a)(5) 20.2203(a)(2)(v) 50.73(a)(2)(i)(A) 50.73(a)(2)(v)(C)
OTHER 20.2203(a)(2)(vi) 50.73(a)(2)(i)(B) 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 NRC Form 366A) (17)
E.
Corrective Actions
A temporary modification was installed to eliminate the identified single failure vulnerabilities.
The Corrective Action to Prevent Recurrence is currently in place as a result of the Configuration Change procedures used to install new designs at Exelon facilities. Separation and Station Single Point Vulnerability reviews, Exelon Human Performance Technical Rigor Standards, and failure mode and effect conditions are part of the preparation and review process contained in existing Exelon procedures.
A permanent modification to the circuitry to eliminate the single failure vulnerability will be designed and installed.
A preliminary DNPS engineering review for similar existing latent design deficiencies found no other similar deficiencies. A corrective action is in place for engineering to complete an extent of condition review of the alternating current, Emergency Diesel Generators, and direct current systems for latent design deficiency conditions similar to this event.
DNPS engineering will review this event as part of group discussions to raise awareness of common circuits and the potential to affect more than one train of equipment.
DNPS engineering will include a description of this event in continuing engineering training to raise awareness of common circuits and their potential to affect more than one train of equipment.
F.
Previous Occurrences
A review of DNPS Licensee Event Reports (LERs) identified no similar events.
G.
Component Failure Data
NA