05000373/LER-2002-001, Missing Cooling Coil Mounting Plate Screws in Three Safety Related Room Coolers Render & Associated Safety Systems Inoperable
| ML030280534 | |
| Person / Time | |
|---|---|
| Site: | LaSalle  |
| Issue date: | 01/21/2003 |
| From: | Landahl S Exelon Generation Co, Exelon Nuclear |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| LER 02-001-00 | |
| Download: ML030280534 (4) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2) |
| 3732002001R00 - NRC Website | |
text
- 1 Exe Ie n S.
Exelon Generation Company, LLC LaSalle County Station 2601 North 21'Road Marseilles, IL 61341-9757 www exeloncorp corn Nuclear January 21, 2003 10 CFR 50.73 United States Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555 LaSalle County Station, Units 1 and 2 Facility Operating License Nos. NPF-11 and NPF-18 NRC Docket Nos. 50-373 and 50-374
Subject:
Licensee Event Report In accordance with 10 CFR 50.73(a)(2)(v)(D) and (a)(2)(ii)(B), Exelon Generation Company, (EGC), LLC, is submitting Licensee Event Report Number 02-001-00, Docket No. 050-373.
Should you have any questions concerning this letter, please contact Mr. Glen Kaegi, Regulatory Assurance Manager, at (815) 415-2800.
Respectfully, 9Sus
. Landahi
\\,Plant Manager LaSalle County Station Attachments:
Licensee Event Report cc:
Regional Administrator - N RC Region Ill NRC Senior Resident Inspector - LaSalle County Station I,
NR&rFORMI 366 U.S. NUCLEAR REGULATORY APPROVED BY ONIB NO. 3150-0104 EXPIRES 7-31-2004 (7-2001)
COMMISSION
, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
I. FACILITY NAME LaSalle County Station, Unit 1
- 2. DOCKET NUMBER
- 3. PAGE 05000373 1 of 3 4.TITLE Missing Cooling Coil Mounting Plate Screws in Three Safety Related Room Coolers Render the Associated Safety Systems Inoperable
- 5. EVENT DATE
- 6. LER NUMBER
- 7.
REPORT DATE
- 8. OTHER FACILITIES INVOLVED MO1 DAY YEAR YEAR SEQUENTIAL REV MIO DAY YEAR StFACILITY NAME NUMBER NO LaSalle County DOCKETNUMBER
__Station, Unit 2
05000374 11 21 2002 2002 001 00 01 21 03 FACILITY NAME DOCKETNUMBER
- 9. OPERATING 1
l. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply)
MODE
- 10. POWNER 10 LEVEL 10_0 7_
[] 202201(b)
E] 202203(a)(3)(ii) 5073(a)(2)(n)(B)
[]
5073(a)(2)(ix)(A)
E* 20 2201 (d) 0]
20.2203(a)(4) 0 50 73(a)(2)(in) 50 73(a)(2)(x) l0 20 2203(a)(1)
E0 50 36(c)(l)(l)(A) 0 50.73(a)(2)(iv)(A) 0 73.71(a)(4)
El 20 2203(a)(2)(i) 0 50 36(c)(1)(ii)(A)
EI 50-73(a)(2)(v)(A) 0 73 71(a)(5) fi [7] 202203(a)(2)(i)
] 5036(c)(2) 0 5073(a)(2)(v)(B)
E OTHER C
20 2203(a)(2)(iii)
L0 50 46(a)(3)(ii)
[J 50 73(a)(2)(v)(C)
Specify in Abstract below or in NRC From 366A 2]
20 2203(a)(2)(v) 50 73(a)(2)(1)(A) 50 73(a)(2)(v)(D) 2l 20 2203(a)(2)(v) 50 73(a)(2)(i)(B) 50 73(a)(2)(vii)
] 20 2203(a)(2)(v)
El 50 73(a)(2)(1)(C)
[]
50 73(a)(2)(viii)(A)
El 20 2203(a)(3)(i)
E 50.73(a)(2)(n)(A) 50 73(a)(2)(viu)(B)
- 12. LICENSEE CONTACT FOR T}IlS LER NAME TELEPHONE NUMBER (Include Area Code)
Steve Smalley, System Engineering l (815) 415-2779LE CE SYSTEM COMPONENT NIANU-REPORTABLE ACTURER TO EPIX G
FACTUARER TO EPIX
- 14. SUPPLEMENTAL REPORT EXPECTED
- 15. EXPECTED MONTH DAY YEAR I
YES NO SUBMISSION 03 31 03 (If yes, complete EXPECTED SUBMISSION DATE) l DATE
ABSTRACT
On November 21, 2002, during inspection of the Unit 2 High Pressure Core Spray (HP) 2VY02A area cooler, several one-quarter inch sheet metal screws used to mount the cooling coils to the frame inside the cooler were observed to be missing.
On November 22, 2002, it was determined that the missing screws could have prevented the HP system, a single train safety system, from performing its design function during a seismic event.
An extent of condition review found screws also missing from the Unit 1 Division 2 area cooler IVY03A and the Unit 2 Division 2 area cooler 2VY03A.
The systems were removed from service, the coolers were repaired, and the systems were returned to operable status as the conditions were identified. The significance of this condition was that, with the area coolers inoperable, the associated ECCS pumps might not have performed their safety function during a seismic event. On Unit 2, both Divisions 2 and 3 were affected.
The cause of the missing screws could not be identified; however, a contributing cause was that the condition may have gone unobserved or unreported for several years.
Corrective actions, including training, will be taken to assure that such conditions are identified and corrected.
NRC FORM 366 (7-2001)
NRCFORNI 366A U.S. NUCLEAR REGULATORY CO1MMISSION
_(7-2001)
LICENSEE EVENT REPORT (LER)
- 6. LER NUMBER
- 3. PAGE YEAR SEQUENTIAL REVISION YEA NUTER NUMBER LaSalle County Station, Unit 1 05000373 02 001 00 2 of 3
- 17. NARRATIVE (If more space is required, use additional copies of (If more space is required, use additional copies of NRC Form 366A) or unreported for several years, even though there were opportunities for Maintenance and Engineering personnel to identify it during work or testing activities inside the cooler.
Because these screws are internal to the cooler enclosure, operations personnel did not have an opportunity to identify this issue during plant walkdowns and routine tours.
D.
SAFETY ANALYSIS
There were no safety consequences from this event, because no seismic events occurred during the time the screws were not installed.
While the likelihood of a seismic event of sufficient magnitude to approach the design basis earthquake (DBE) load is low, the consequences of a DBE had the coolers been degraded could be significant.
The affected coolers would not function, which would eventually lead to the loss of important safeguards equipment used to achieve a safe shutdown of the plant.
The condition was most limiting on Unit 2, because the both Division 2 and Division 3 were affected.
Division 1 systems were operable.
A structural analysis is in progress to evaluate the effects of a seismic event on the three affected divisional coolers.
The results of this evaluation may lead to a conclusion that one or more of the coolers was actually operable with the missing screws, which would affect the actual risk significance aspect of this event.
A supplement to this LER will be issued to update the significance when the structural analysis is complete.
E.
CORRECTIVE ACTIONS
- 1. LTS-200-19, "ECCS Cubicle Area Cooler Air Flowrate Test," will be revised to include a specific check and signoff for the presence of these and any other required fasteners inside the cooler as part of the visual inspection for materiel condition (AT# 132704-22).
- 2. Training material will be developed for this event and incorporated into continuous training for appropriate personnel (AT# 132704-25, 26, and 27).
- 3. A review of station safety related surveillances will be done to insure each has a clear requirement to conduct a general material condition review of any area opened up for the conduct of the surveillance prior to closeout (AT# 132704-28 & 29).
- 4. A structural analysis for historical operability will be performed (AT# 132704-35).
F.
PREVIOUS OCCURRENCES
No previously identified instances of missing cooling coil mounting plate screws was identified.
A previous instance of missing and/or loose fasteners was identified in January 2000, and regarded missing fasteners on instrument mounting brackets.
Corrective actions were created to make personnel sensitive to, and to specifically check for, missing/loose fasteners during routine work (e.g.,
maintenance work, operator rounds, system walkdowns).
This action was presented for awareness not as formal training, and was not effective in identifying this condition earlier.
G.
COMPONENT FAILURE DATA
Not applicable, as no components failed in this event.