05000271/LER-2007-001, Re High Pressure Coolant Injection System Isolation Time Delay Relay Surveillance Test Failures Due to an Inadequate Calibration Methodology
| ML071730043 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 06/18/2007 |
| From: | Ted Sullivan Entergy Nuclear Operations |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| BVY 07-042 LER 07-001-00 | |
| Download: ML071730043 (4) | |
| 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)(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)(v), Loss of Safety Function |
| 2712007001R00 - NRC Website | |
text
SEn tergy Entergy Nuclear Operations, Inc.
Vermont Yankee P.O. Box 0500 185 Old Ferry Road Brattleboro, VT 05302-0500 Tel 802 257 5271 June 18, 2007 BVY 07-042 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555
Subject:
Vermont Yankee Nuclear Power Station License No. DPR-28 Docket Number: 05000271 Reportable Occurrence Number: LER 2007-001-00
Dear Sir or Madam,
As defined by 10 CFR 50.73(a)(2)(i)(B), we are submitting the attached Licensee Event Report, LER 2007-001-00, for a Reportable Occurrence that was discovered on April 24, 2007.
There are no regulatory commitments contained within this correspondence.
Sincerely, Ver ankee Nuclear Power Station cc:
USNRC Region I Administrator USNRC Resident Inspector - VYNPS USNRC Project Manager - VYNPS Vermont Department of Public Service
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 06/30/2007 (6-2004)
, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
- 4. TITLE High Pressure Coolant Injection System Isolation Time Delay Relay Surveillance Test Failures due to Inadequate an Calibration Methodology.
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED MONTH DAY YEAR YEAR SEQUENTIAL REV MONTH DAY YEAR FACILITY NAME DOCKET NUMBER NUMBER NO.
N/A FACILITY NAME DOCKET NUMBER 04 24 2007 2007 001 00 06 18 2007 N/A
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply)
O 20.2201(b) jJ 20.2203(a)(3)(i)
Q 50.73(a)(2)(i)(C)
E] 50.73(a)(2)(vii)
N Q 20.2201(d)
[
20.2203(a)(3)(ii)
[
50.73(a)(2)(ii)(A)
[]
50.73(a)(2)(viii)(A)
O] 20.2203(a)(1)
[
20.2203(a)(4) 50.73(a)(2)(ii)(B)
E] 50.73(a)(2)(viii)(B)
O 20.2203(a)(2)(i) 5 50.36(c)(1)(i)(A) 5 50.73(a)(2)(iii) 5 50.73(a)(2)(ix)(A)
- 10. POWER LEVEL 20.2203(a)(2)(ii) 5 50.36(c)(1)(ii)(A) 5 50.73(a)(2)(iv)(A) 5 50.73(a)(2)(x) 5 20.2203(a)(2)(iii) 5 50.36(c)(2) 5 50.73(a)(2)(v)(A) 5 73.71 (a)(4) 100 5 20.2203(a)(2)(iv) 5 50.46(a)(3)(ii) 5 50.73(a)(2)(v)(B) 5 73.71 (a)(5)
O 20.2203(a)(2)(v) 5 50.73(a)(2)(i)(A) 5 50.73(a)(2)(v)(C)
El OTHER Fl 20.2203(a)(2)(vi)
Ej 50.73(a)(2)(i)(B)
[] 50.73(a)(2)(v)(D)
Specify in Abstract below or in
ASSESSMENT OF SAFETY CONSEQUENCES
The HPCI system is designed to supply high pressure coolant to the reactor core, to prevent excessive fuel clad temperatures, in the event of a small-break loss of coolant accident (LOCA) that does not result in a rapid depressurization of the reactor vessel, and can supply reactor makeup during periods when the Feedwater System is isolated or otherwise unavailable. The condition described within this LER would not have prevented the HPCI system from performing the design safety functions listed above at any time.
The "B" channel HPCI isolation logic relay (23A-K48) successfully passed all calibration tests performed during the period when the "A" channel relay deficiencies existed. Due to the redundant design of the isolation logic, the HPCI Isolation Trip System would have ensured that a timely HPCI system isolation occurred if required, thereby maintaining the design function of the system. Because the "B" Trip System was fully operable, the HPCI system would have isolated within the Technical Specification limit of 35 minutes in the event of a main steam tunnel high temperature condition.
The delayed isolation safety analysis that evaluates the impact on other safety related 'components assumes that the isolation occurs in 40 minutes. Therefore, since the actual isolation times are bounded by the time assumed in the analysis, these events did not have any increase in risk to the health and safety of the public.
CORRECTIVE ACTIONS
Immediate Actions
- 1) The condition described by this LER was entered into the Entergy Corrective Action Program and promptly shared with the Entergy Fleet and subsequently shared with the nuclear industry on 06/01/2007 through the Operating Experience Program processes.
- 3) Reviewed the manufacturer's (Agastat) literature for applicable models in use at VY to determine if similar information may have been overlooked as a result of a complex presentation for information regarding relay calibration methodology within the manufacturer's literature that may have impacted other VY components and/or procedures. No additional issues were identified Previously Implemented Actions
- 1) Revised the surveillance procedure for the HPCI isolation time delay relays (23A-K48 and 23A-K49) to implement the improved methodology in accordance with manufacturer recommendations during operation cycle 25.
- 2) Revised the surveillance procedure for the RCIC system isolation time delay relays (13A-K41 and 13A-K42) to implement the improved methodology in accordance with manufacturer recommendations during operation cycle 25.
Long Term Action Perform an additional check of the HPCI relay (23A-K49) during operation cycle 26 to confirm that actions taken have resolved the condition.
ADDITIONAL INFORMATION
No similar events have occurred at VY within the past ten years.