05000333/LER-2007-002, (Jaf) Re Manual Reactor Scram Due to Blocked Circulating Water Intake Screens
| ML073270053 | |
| Person / Time | |
|---|---|
| Site: | FitzPatrick  |
| Issue date: | 11/13/2007 |
| From: | Peter Dietrich Entergy Nuclear Northeast, Entergy Nuclear Operations |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| JAFP-07-0127 LER 07-002-00 | |
| Download: ML073270053 (7) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(iv)(A), System Actuation |
| 3332007002R00 - NRC Website | |
text
En tergy Entergy Nuclear Northeast Entergy Nuclear Operations, Inc.
James A. Fitzpatrick NPP P.O. Box 110 Lycoming, NY 13093 Tel 315 349 6024 Fax 315 349 6480 Pete Dietrich Site Vice President - JAF November 13, 2007 JAFP-07-0127 United States Nuclear Regulatory Commission Attn: Document Control Desk Mail Station P1-137 Washington, D.C. 20555
Subject:
Docket No. 50-333 LICENSEE EVENT REPORT: LER-07-002 (CR-JAF-2007-03202)
Manual Reactor Scram due to Blocked Circulating Water Intake Screens.
Dear Sir or Madam:
This report is submitted in accordance with 10 CFR 50.73(a)(2)(iv)(A), "Any event or condition that resulted in manual or automatic actuation of any of the systems listed in (a)(2)(iv)(B), including the Reactor Protection System and general containment isolation signals affecting isolation valves in more than one system (Group 2 isolation).
There are no commitments contained in this report.
Questions concerning this report may be addressed to Mr. Jim Costedio at (315) 349-6358..,
PD:tp Enclosure cc:
USNRC, Region 1 USNRC, Project Directorate USNRC Resident Inspector INPO Records Center
Abstract
On September 12, 2007, while the plant was operating at 100 percent power, operators inserted a manual reactor scram due to low intake flow caused by traveling water screen (TWS) blockage. All equipment responded as expected and the plant condition was stable in MODE 3, Hot Shutdown. While transitioning to Mode 4, the Reactor Protection System (RPS) automatically actuated when Reactor Pressure Vessel (RPV) level decreased to less than 177 inches above top of active fuel (TAV). This event was reported as NRC Event 43635 pursuant to 10CFR50.72(b)(2)(iv)(B) for RPS actuation (manual scram)
(4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> report) and 10CFR50.72(b)(3)(iv)(A) for specified system actuation (Group 2 PCIS isolations) (8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> report).
The cause of the manual scram was determined to be due to environmental debris overloading of the traveling screens, and the cause of the RPS signal was determined to be sluggish operation of the feed water startup flow control valve. The safety significance of this event is considered low and did not decrease the effectiveness of plant barriers from providing safety to the.public.
On October 28, 2007, while the root cause evaluation was in progress for the TWS blockage event, a similar event involving TWS screen blockage occurred that resulted in a manual scram (NRC Event 43752). Following completion of the root cause analysis this LER will be updated to address both events.
NRC FORM 366 (9-2007)
(If more space is required, use additional copies of (If more space is required, use additional copies of (If more space is required, use additional copies of (If more space is required, use additional copies of (If more space is required, use additional copies of NRC Form 366A)
REFERENCES:
- 1.
Post Transient Evaluation (PTE) No.07-002, dated 9/12/2007.
- 2.
INPO SER 6-03, "Cooling Water System Debris Intrusion"
- 3.
INPO SER 84-04, "Reactor Trips Caused by Main Feedwater Control Problems"