NL-08-117, Report on Inoperable Post Accident Monitoring Instrument LT-3300
| ML082180529 | |
| Person / Time | |
|---|---|
| Site: | Indian Point  |
| Issue date: | 07/24/2008 |
| From: | Robert Walpole Entergy Nuclear Operations |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| NL-08-117 | |
| Download: ML082180529 (2) | |
Text
- Entergy Indian Point Energy Center 450 Broadway, GSB P.O. Box 249 Buchanan, N.Y. 10511-0249 Tel (914) 734-6700 July 24, 2008 Indian Point Unit 2 Docket 50-247 NL-08-117 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001
SUBJECT:
Report on Inoperable Post Accident Monitoring Instrument LT-3300
Dear Sir or Madam:
The purpose of this letter is to submit a report pursuant to Technical Specification (TS) 5.6.6, in accordance with the action required by TS 3.3.3, "Post Accident Monitoring (PAM)
Instrumentation," and Technical Requirements Manual (TRM) 3.3.L, "Containment/Recirculation Sump Level Indication," Condition B which requires a report to be submitted within 14 days of exceeding the allowed outage time of TS 3.3.3 and TRM 3.3.L, Condition A for specified Post Accident Monitoring (PAM) instruments. Pursuant to TS 5.6.6, the report is to outline the alternate method of monitoring, the cause of the inoperability, and the plans and schedule for restoring the instrument to operable status.
PAM instrument LT-3300 is required to be operable in Modes 1, 2, and 3 by TS 3.3.3, Table 3.3.3-1, Function 6 "Containment Water Level (Containment Sump)." During a recent containment pressure relief an unexpected response by containment sump level transmitter LT-3300 was identified. Test 2-PT-M045, "Vapor Containment Sump Pumps," was completed satisfactorily on June 8, 2008 indicating LT-3300 responded appropriately during the test and tracks as required with containment sump pump operation. Operations concluded that LT-3300 was operable as a Reactor coolant System leakage detection instrument required for TS 3.4.15.
An engineering review of the operability of LT-3300 concluded that the effects on LT-3300 due to small changes in containment pressures during normal operation were minimal, but the possible effects due to post accident containment pressure changes could be significant and not quantifiable. On June 11, 2008, Operations declared LT-3300 inoperable per TS 3.3.3 and non-functional per TRM 3.3.L. TS 3.3.3 and TRM 3.3.L, Condition A required completion time to restore the channel to operable is 30 days. Engineering concluded the possible cause of the inoperability of LT-3300 is a gas bubble in the piping connected to the lower sensor near the sump bottom. A Work Order was generated to remove the Swagelok cap from one of the test connections to remove any gas from the line and then monitor the performance of LT-3300.
Entergy Nuclear Operations, Inc. (Entergy) repair plan requires a refueling outage or a suitable forced outage and is, therefore, submitting this letter to meet TS requirements. The planned deferral of work on LT-3300 is based on the harsh work environment (i.e., high radiation fields and ambient temperature inside the crane wall), the uncertain nature of the problem (inspections and testing will be required to verify the cause of the failure), and the potential inability to perform on-line post work testing, based on the nature of the corrective action.
NL-08-117 Docket 50-247 Page 2 of 2 The backup method of monitoring the Containment Sump is LT-941. Level Transmitter LT-941 is powered from a diverse safeguards power train and monitors containment sump level by illuminating a series of 5 lights in the control room if preset limits are exceeded. An enhanced capability was added during the last outage that provides recording and display capability via the plant computer for LT-941. This level transmitter is seismically and environmentally qualified.
As the post accident containment building water level will be above both the containment sump and the recirculation sump, an alternate method of monitoring post accident containment water level is by recirculation sump level monitor LT-3301. The planned corrective action for LT-3300 is to clear the gas void from the sensor line to the transmitter during the next refuel outage scheduled the spring of 2010 or during a forced outage, if practicable. Inspections and testing will be performed to determine if the corrective action resolved the issue. Any additional actions required will be processed in accordance with the Indian Point Energy Center Corrective Action Program.
There are no new commitments being made in this submittal.
If you have any questions or require additional information, please contact Mr. Robert Walpole, Licensing Manager, at 914-734-6710.
Sincerely, Mr. Robert alpole Licensing Manager Indian Point Energy Center cc:
Mr. John P. Boska, Senior Project Manager, NRC NRR Mr. Samuel J. Collins, Regional Administrator, NRC Region 1 NRC Resident Inspector, IP2 Mr. Paul Eddy, New York State Dept. of Public Service