ML25174A178
| ML25174A178 | |
| Person / Time | |
|---|---|
| Site: | Cooper  |
| Issue date: | 06/20/2025 |
| From: | Dewhirst L Nebraska Public Power District (NPPD) |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 57770 | |
| Download: ML25174A178 (1) | |
Text
From:
Dewhirst, Linda R.
To:
Hoc, HOO X
Subject:
[External_Sender] Part 21 Notification - Cooper Nuclear Station Date:
Friday, June 20, 2025 10:52:41 AM Attachments:
image001.png Part 21 Notification Cooper Nuclear Station.pdf Please see attached, I will be calling shortly.
Pase I ot 2 NRC FORM 351 (08-1s-2O24)
U.S. NUCLEAR REGULATORY COMMISSION OPERATIONS CENTER
{W REACTOR PLANT EVENT NOTIFIGATION WORKSHEET APPROVED BY OMB: NO. 3150-0238 EXPIRES: 0713112026 Eslimalod burden pt rosponse to comply with lhis voluntary @llslion requesl: 30 minuts. The infomalion provided will bo used for ovalualion of li@nsoo event dosriplion, facility slatus and fo. input lo the publio wobsile. Send @mmsots rogarding burdn eslimate lo lhe FOIA, Library, and lnlolmation Colleclions Branch (T'6 A10M), U.S. Nucloar Regulalory Commission, Washinglon, DC 20555-0001, or by omail lo Infeollocls.Resource@nrc.oov, and and lhe Ol,iB reviewer ati OMB Offco of lnformation and Regulatory Aftahs, (3150-0238), Alln:
Desk Offi@r fot th Nuclear Regulatory Commission, 725 17lh Slreet NW, Washinglon, DC 20503. The NRC may not mnduct or sponsor, and a prson is nol rcquird to rsspond to, a colleilon of inlormalion unloss the document rqusling or requiring the coll@lion displays a currnlly valid OlllB control number.
EN#
NRCOPERATIONSTELEPHONENUMBERS:
PRIMARY-301-816-5100or800-532-3469+,BACKUPS-[1st]301-951-O55Oor800-449-3694+,
[2nd] 301-415-0550and[3rd] 301-a15-0553. *LicenseeswhomaintaintheirownETSareprovidedthesetelephonenumbers.
FAX - 301-816-5151, EMAIL - hoo.hoc@nrc.gov Notification Time Facility or Organization Cooper Nuclear Unit 1
Name of Caller/Title Linda DewhirsURegulatory Affairs Mgr Call Back #
402-825-5416 Event Time & Zone 0000 cDT Event Date 5t22t2025 Power/Mode (At Time of Event) 100o/ol1 Power/Mode (At Time of Notification) 100o/ol1 EVENT CLASSIFICATION 1-HR. NON-EMERGENCY,t0 CFR 50.72(bX1) fl tulfnl sare s/D capabirjry AINA ceuennr-EvTERGENcy GEN/AAEC n TS Deviation ADEV I tuXal RHR capability AINB srrennenEMERGENcY SIT/AAEC 4-HR. NON-EMERGENCY 10 CFR 50.72(bl(21 !
tul<cl Control of Rad Release AINC
! nlenr ALE/AAEC fl til rs Required s/D ASHU !
tultol Accident Mitigation AIND uruusuRlevenr UNU/AAEC !
tiu)tn) ECcs Discharge to Rcs ACCS !
t"iu Offsite lvledical AMED I
so.zz NoN-EMERGENcv (see next columns) !
ARPS f] t'iri)
Loss Comm/Asmt/Response ACOM rocrnzs D??? I
("il Otfsite Notification APRE 60-DAY OPTIONAL 10 cFR 50.73(a)(1) unrennuExposuRE B??? 8-HR. NON-EMERGENCY 10 CFR 50.72(bX3) n lnvalid Specified System Acluation AINV I
rrrruess FoR DUry HFIT !
tiiltnl Degraded condition ADEG OTHER UNSPECIFIED REQUIREMENT (IDENTIFYI fl OrHen UNSPEClFlED REQMT. (see tast cotumn) !
tilltel unanalyzed condilion AUNA a 10 cFR 21.21(dX3Xi)
NONR truronunrroN oNLy NNF I CuXn) Specified System Actuation AESF n NONR Event Description (lnclude: Systems affected, actuations and their initiating signals, causes, effect of event on plant, actions taken or planned, elc.) (Continue on page 2)
Part 21 Report - Diesel Generator Jacket Water Pump Failure On April 8,2025, while in Mode 1 and at 100 percent power, during performance of a scheduled monthly surveillance test, Nebraska Public Power District (NPPD) Cooper Nuclear Station (CNS) identified Diesel Generator (DG) 1 jacket water (DGJW) pump may not be providing sufficient cooling water to the DG. The DGiW pump impeller was found to have slipped on the shaft as a result of a failure to achieve the required interference fit during preventive maintenance replacing the pump seal. On May 22,2025, subsequent investigation identified a deviation in that the originally supplied Cooper-Bessemer DGJW impeller bore was not provided in accordance with the design drawing. Due to the bore dimensional deviation, the required interference fit was not achieved, resulting in shaft rotational and torsional forces challenging the compromised fit until the impeller was able to spin freely on the shaft.
On June 19,2025, NPPD completed an evaluation and determined that the deviation represents a defect that could create a substantial safety hazard as defined in 10 CFR 21, as this pump was approved for use in a safety application.
NPPD is not aware of any other plants being impacted by this issue.
The NRC Resident lnspector has been notified. A written notification will be provided within 30 days.
NOTIFICATIONS YES NO WILL BE Anything Unusual or not understood? !
Ves (Explain above) Z tlo NRC RESIDENT z
n n
STATE(s) n n
n Did all systems function as required? [
Ves f] No (Exptain above)
LOCAL tr z
n OTHER GOV AGENCIES n
a n
Mode of operations until corrected (if applicable)
MEDIA/PRESS RELEASE T
a T
Additional lnformation continued on next page? [ Ves E Xo NRC FORM 361 (08-15-2024)
eage L or 2-NRC FORM 361 (08-15-2024)
U.S. NUCLEAR REGULATORY COMMISSION REACTOR PLANT EVENT NOTIFICATION WORKSHEET (Gontinued)
OPERATIONS CENTER EN#
RADIOLOGICAL RELEASES: CHECK OR FILL lN APPLICABLE ITEMS (specific details/explanations should be covered in event description)
I Liquid Release T
Gaseous Release T
Unplanned Release T
Planned Release X
ongoing I
Terminated T
Monitored r
Unmonitored tr Offsite Release u
T.S. Exceeded T
RM Alarms I Areas Evacuated T
Personnel Exposed or Contaminated T
Offsite Protection Actions Recommended
- State release path in description Release Rate (Ci/sec) o/o T.S. Limit HOO Guide Total Activity (Gi)
% T.S. Limit HOO Guide Noble Gas 0.1 Gi/sec 1000 ci lodine 10 pci/sec 0.01 ci Particulate
,l pGi/sec 1 mci Liquid (excluding tritium and dissolved noble gas) 10 pCi/min 0.1 ci Liquid (tritium) 0.2 Ci/min 5Ci TOTAL Plant Stack Condenser/Air Ejector Main Steam Line SG Blowdown Other RAD Monitor Readings Alarm Setpoints
% T.S. Limit (lf applicable)
RCS OR SG TUBE LEAKS: CHECK OR FILL lN APPLICABLE ITEMS: (specific detaits/exptanations should be covered in event description)
Location of the Leak (e.9., SG #, valve, pipe, etc.)
Leak Rate Units: gpm/gpd T. S. Limits Sudden or Long-Term Development Leak Start Date Time Primary Secondary Coolant Activity and Units:
List of Safety Related Equipment not Operational NRC FORM 361 (08-15-2024)