05000440/LER-2003-004-01, Regarding Emergency Service Water Pump Upper Shaft Coupling Sleeve Failure
| ML040410619 | |
| Person / Time | |
|---|---|
| Site: | Perry  |
| Issue date: | 01/29/2004 |
| From: | Kanda W FirstEnergy Nuclear Operating Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| PY-CEI/NRR-2765L LER 03-004-01 | |
| Download: ML040410619 (8) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 4402003004R01 - NRC Website | |
text
.
N.
FENOC Perry Nuclear Power Plant 10 Center Road FtrstEnergy NuclearOperating Company Perry Ohio 44081 William R. Kanda 440-280-5579 Vice President - Nuclear Fax: 440-280-8029 January 29, 2004 PY-CEIINRR-2765L United States Nuclear Regulatory Commission Document Control Desk Washington, D.C. 20555 Perry Nuclear Power Plant Docket Number 50-440 LER 2003-004-01 Ladies and Gentlemen:
Enclosed is revision I to Licensee Event Report (LER) 2003-004, Emergency Service Water Pump Upper Shaft Coupling Sleeve Failure. This event report is submitted in accordance with IOCFR50.73(a)(2)(i)(B), as an operation or condition prohibited by Technical Specifications.
The revision to the LER provides updated information to align the risk assessment contained in the LER with the risk analysis submitted to the NRC'on December 23, 2003 (Perry letter number PY-CEI/NRR-2758L).
We received and acknowledge the letter transmitting the final significance determination for a white finding and Notice of Violation dated January 28, 2004. Submittal of the revised LER provides consistency with the assessment contained in our letter submitted December 23, 2003. This revision also updates corrective actions to reflect those actions completed to date. Revision bars contained in the LER margin identify revised LER text.
The root cause for this event was discussed at the Regulatory Conference held at the Region III offices on December 17, 2003. We understand the concerns that were voiced in this meeting and we are conducting further review of our root cause analysis. We will provide further correspondence if there are any substantive changes to the information provided to date.
There are no regulatory commitments contained in this submittal. Any actions discussed in this document that represent intended or planned actions, are described for the-NRC's information; and are not regulatory-
commitments
If you have questions or require additional information, please contact Mr. Vernon Higaki, Manager-Regulatory Affairs, at (440) 280-5294.
Very tuly yours, I
Enclosure
- z-i;
- 1t
',.,,:.',,:t.a:,w
',jn',,
cc:
-: NRC Region III Administrator-
- ti NRC Senior Resident Inspector -PNPP
- i-;;
i 1 NRR Project Manager - PNPP
- ~~~~~ji A
Abstract
On September 1, 2003, at 1717 hours0.0199 days <br />0.477 hours <br />0.00284 weeks <br />6.533185e-4 months <br /> with the plant operating in Mode 1 at 100 percent power, emergency service.water (ESW) pump.A was declared inoperable due to indications that the.pump _
had failed. It was later determined that a pump shaft coupling had failed and that it would take longer than the Technical Specification (TS) Limiting Condition for Operation (LCO) completion time to complete repairs. A Notice of Enforcement Discretion (NOED) was requested of the NRC in order to obtain replacement parts, complete repairs and perform testing of the pump. The NOED for a 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> duration was verbally approved on September 4, 2003. At 0517 hours0.00598 days <br />0.144 hours <br />8.54828e-4 weeks <br />1.967185e-4 months <br /> on September 5, 2003 the LCO for TS 3.7.1 and 3.8.1 expired and the plant entered the NOED. After completion of repairs, ESW A pump was declared operable at 1855 hours0.0215 days <br />0.515 hours <br />0.00307 weeks <br />7.058275e-4 months <br /> on September 5, 2003. The root cause of the coupling sleeve failure is stress corrosion cracking. This event is considered to have a low safety significance. Since the Actions of the TSs were not satisfied when the NOED was entered, this is a reportable event in accordance with 1 OCFR50.73(a)(2)(i)(B), any operation or condition that was prohibited by the plant's TSs.
NRC FORM 366 (7-2001)
(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 (f more space is required, use additional copies of NRC Form 366.A) (17)A blended approach was applied for assessment of the effect of a seismic event due to an operational basis earthquake. The ESW A pump being unavailable for 13.5 days results in an ICCDP of about 4.4E-08 for the seismic event. Results from the FIVE analyses were used for the fire assessment. Fire induced plant indicators that rely upon ESW A for mitigation and would result in an increase in core damage frequency were assessed. A conditional core damage probability
_ was computed for the configuration with-and.without.the ESW A pump failure. The increase in CCDP for each fire area assessed was summed to get a total increase in the CDF. For the 13.5 day period when ESW was not available, the ICCDP due to fires is approximately 7.8E-08.
Extemal flooding was considered non-significant due to the shape and composition of the terrain surrounding the plant. The combined ICCDP for seismic, fire and external events is approximately 1.2E-07. The ICCDP for all events (including internal flooding and external events) is approximately 9.7E-07.
The failure of ESW pump A also had an impact on the large early release frequency (LERF). The assessment of LERF did not partition the risk or reduce the number of unrealistic event sequences.
However, the changes made in the assessment of CDF would have a comparable effect to also reduce LERF and it is predicted that the Incremental Conditional Large Early Release Probability (ICLERP) is about 7.7E-08. Qualitatively, the ICLERP associated with the unavailability of ESW A pump for 13.5 days is less than 1.OE-07.
In conclusion, the failure of the ESW A pump is considered to have low safety significance.
V)
CORRECTIVE ACTIONS
This event was entered into the PNPP corrective action program (Condition Report 03-05065).
A rebuild of the ESW.A pump was completed on September 5, 2003, and the pump was declared
coupling sleeve installation was verified.
A rebuild / replacement of the ESW A pump is being planned for the Division I outage, scheduled for March 2004. A complete pump except for the discharge head is ordered. An engineering change upgrades the materials for the impellers, diffuser bowls, suction bell, pump shafts and coupling sleeves. A revision to the purchase specification for ESW A pump was made to provide certified material test reports (CMTRs) for all parts essential to function including shafts, coupling sleeves, split rings, coupling keys, impeller split ring and the impeller key. Nondestructive examination (NDE) of the coupling sleeves was specified.
A limited boroscopic examination of the ESW C pump was performed during the Division IlIl outage in November 2003 and confirmed that the installed couplings are of the threaded design. No conditions were identified that would require immediate pump shaft coupling maintenance.
A rebuild of the ESW C pump is being planned for the first Division 3 outage in 2004 (currently scheduled for April 2004). A complete pump, except for the discharge head, is ordered for the (If more space is required, use additional copies of (f more space is required, use additional copies of NRC Form 366A) (17)
I VI) PREVIOUS SIMILAR EVENTS A review of LERs over the past 6 years did not identify any reportable condition that resulted from the failure of a pump coupling.
A word search was performed to identify Condition Reports at the PNPP relating to pumps or coupling sleeves. This review did not identify any Martensitic or type 416 stainless steel couplings that failed due.to stress corrosion cracking..in rawwater service..-No evidence of a previous ESVV pump coupling sleeve failure was found.
VII) COMMITMENTS No regulatory commitments were identified in this report.
Energy Industry Identification System Codes are identified in the text by square brackets [XX].
_- -- I