05000410/LER-2001-007, Re Manual Reactor Scram Due to Unidentified Drywell Leakage
| ML020590459 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 02/13/2002 |
| From: | Peckham M Constellation Nuclear |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| NMP2L 2049 LER-01-007-00 | |
| Download: ML020590459 (5) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(A), Completion of TS Shutdown 10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition 10 CFR 50.73(a)(2)(ix)(A) 10 CFR 50.73(a)(2)(iii) 10 CFR 50.73(a)(2) 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)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(viii)(A) 10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded 10 CFR 50.73(a)(2)(viii)(B) |
| 4102001007R00 - NRC Website | |
text
P.O. Box 63 Lycoming, New York 13093 Constellation Nuclear Nine Mile Point Nuclear Station February 13, 2002 NMP2L 2049 A Member of the Constellation Energy Group United States Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555 RE:
Nine Mile Point Unit 2 Docket No. 50-410 NPF-69
Subject:
Licensee Event Report 01-007, "Manual Reactor Scram Due to Unidentified Drywell Leakage" Gentlemen:
In accordance with 10 CFR 50.73(a)(2)(i)(A) and 10 CFR 50.73(a)(2)(iv)(A), we are submitting Licensee Event Report 01-007, "Manual Reactor Scram Due to Unidentified Drywell Leakage."
Very truly yours, hl F. Peckham Unit 2 Plant General Manager MFP/IAA/cld Attachment cc:
Mr. H. J. Miller, NRC Regional Administrator, Region I Mr. G. K. Hunegs, NRC Senior Resident Inspector Records Management
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB NO. 3150-0104 EXPIRES 7-31-2004 (1-2001)
Estimated burden per response to comply with this mandatory information collection request:
50 hours5.787037e-4 days <br />0.0139 hours <br />8.267196e-5 weeks <br />1.9025e-5 months <br />. Reported lessons learned are incorporated into the licensing process and fed back to industry. Send comments regarding burden estimate to the Records Management Branch (T-6 E6), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by internet e-LICENSEE EVENT REPORT (LER) mail to bjslnrc.gov, and to the Desk Officer, Office of Information and Regulatory Affairs, NEOB-10202 (3150-0104), Office of Management and Budget, Washington, DC 20503. If a means used to impose information collection does not display a currently valid OMB control (See reverse for required number of number, the NRC may not conduct or sponsor, and a person is not required to respond to, the digits/characters for each block) information collection.
FACILITY NAME (1)
DOCKET NUMBER (2)
PAGE (3)
Nine Mile Point, Unit 2 05000410 1 OF 4
TITLE (4)
Manual Reactor Scram Due to Unidentified Drywell Leakage EVENT DATE (5)
LER NUMBER (6)
REPORT DATE (7)
OTHER FACILITIES INVOLVED (8)
MO DAY YEAR YEAR SEQUENrnAL REV MO DAY YEAR FACILITY NAME DOCKET NUMBER NUMBER NO N/A 05000 12 15 2001 2001 -
007 -
00 02 13 2002 ACILITY NAME DOCKET NUMBER OPRTN HSRPR S~rN/A 05000 OPERATING THIS REPORT IS UBMITTED) PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply) ( 1)
MODE (9) 1 POWER 060 20.2201 (b) 20.2203(a)(3)(ii) 50.73(a)(2)(ii)(B) 50.73(a)(2)(ix)(A)
LEVEL (10) 20.2201 (d) 20.2203(a)(4) 50.73(a)(2)(iii) 50.73(a)(2)(X) 20 2203(a)(1)
_50.36(c)(1)(i)(A)
X 50.73(a)(2)(iv)(A) 73.71 (a)(4) 20.2203(a)(2)(i) 150.36(c)(1 )(ii)(A) 50.73(a)(2)(v)(A) 73.71 (a)(5) 20.2203(a)(2)(ii) 150.36(c)(2) 50.73(a)(2)(v)(B)
OTHER 20 2203(a)(2)(iii)
_50.46(a)(3)(ii) 50.73(a)(2)(v)(C) 20.2203(a)(2)(iv) x 150.73(a)(2)(i)(A) 50.73(a)(2)(v)(D) 20.2203(a)(2)(v) 50.73(a)(2)(i)(B) 50.73(a)(2)(vii) 2223a(2)(vi) 5.73(a)(2)Ci)(C) 150.73(a)(2)(viii)(A) 1 W-20.2203(a)(3)(i) 50.73(a)(2)(ii)(A) 50.73(a)(2)(viii)(B)
LICENSEE CONTACT FOR THIS LER (12)
NAME ITELEPHONt NUMBEK (include Area coue)
I I
ES (If yes, complete EXPECTED SUBMISSION DATE).
aBSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines) (16)
On December 15, 2001, with Nine Mile Point Unit 2 (NMP2) at approximately 100 percent power, Nine Mile Point Nuclear Station, LLC (NMPNS) identified drywell floor drain leakage approaching the maximum limits of Technical Specification (TS) 3.4.5 for unidentified drywell leakage. Plant shutdown was commenced before reaching any of the limits of TS 3.4.5. Additionally, a strategy was developed to manually scram the reactor if leakage increased to 4 gallons per minute (gpm). With leakage continuing to rise above TS 3.4.5 limits, the applicable limiting conditions for operation (LCOs) were entered. At 2046 hours0.0237 days <br />0.568 hours <br />0.00338 weeks <br />7.78503e-4 months <br />, with reactor core thermal power at approximately 60 percent, a manual reactor scram was initiated after the leak rate exceeded 4 gpm.
The cause of the drywell leakage was determined to be failed packing in a gate valve in the reactor coolant (recirculation) system (RCS). The primary purpose of this valve is to isolate the RCS pump for maintenance. The immediate corrective actions included repacking the valve to stop the leakage and retorquing the remaining similar valves in the RCS to protect against leakage. Plant restart and reactor criticality occurred on December 17, 2001.
The primary cause of the packing failure was determined to be inadequate torque specification from the packing program that is used on the affected valve and three other gate valves in the RCS. By the end of the next refueling outage (Spring 2002), all four gate valves will be repacked with a new type of packing having improved performance characteristics.
NRC FORM 366 (1-2001)
(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) (17)
V. Additional Information
- 1. Failed Components:
a)
A 24-inch gate valve, 2RCS*MOV18A, manufactured by Anchor Darling, used to isolate RCS pump 2RCS*PlA for maintenance.
b)
An automatic level control valve, 2FWS-LV55B, manufactured by Valtek, Inc., used to control reactor water level during low power operation.
- 2.
Previous similar events
a)
Licensee Event Report (LER) 97-06 documents an event where NMP2 experienced a rapid rise in unidentified drywell leakage at 95 percent power. As a result, the reactor was placed in cold shutdown.
This particular problem was traced to a leaking flexible hose that served as the drain line to a flow control valve in the RCS.
b)
In December 1998, a packing leak was noted on 2RCS*MOV1 8B. This valve was, therefore, repacked during Refueling Outage Number 7 in Spring 2000. (This event did not result in a LER.)
- 3. Identification of components referred to in this LER:
Components IEEE 805 System ID IEEE 803A Function Reactor Coolant (Recirculation) System AD N/A Reactor Protection System JC N/A Feedwater System SJ N/A Control Rod Drive System AA N/A Radiation Monitoring System IL N/A Leak Monitoring System IJ N/A Valve AD FCV, ISV Valve SJ LCV Pump AD P
Control Rod AA ROD Radiation Monitors IL MON Alarms (Radiation)
IL RA Reactor Pressure Vessel AD RPV Switch JC HS Drain IJ, AD DRN