05000455/LER-2009-001, Re Late Entry Into Technical Specification Condition Associated with Reactor Coolant System Leakage Characterization Resulting in a Condition Prohibited by Technical Specifications
| ML092370099 | |
| Person / Time | |
|---|---|
| Site: | Byron  |
| Issue date: | 08/24/2009 |
| From: | Enright D Exelon Generation Co, Exelon Nuclear |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| BYRON 2009-0095 LER 09-001-00 | |
| Download: ML092370099 (5) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i) 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded 10 CFR 50.73(a)(2)(viii)(A) 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition 10 CFR 50.73(a)(2)(viii)(B) 10 CFR 50.73(a)(2)(iii) 10 CFR 50.73(a)(2)(ix)(A) 10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2)(x) 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)(i)(A), Completion of TS Shutdown 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 4552009001R00 - NRC Website | |
text
lxcicF' Generation C""p,lny, I 8yron StJt'on 44S0 North Cerm,HI Church >:o,lci Byron, IL 61010,9794 August 24, 2009 Nuclear 10 CFR 50.73 LTR:
BYRON 2009-0095 1.10.0101 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Byron Station, Unit 2 Facility Operating License No. NPF-66 NRC Docket No. STN 50-455
Subject:
Licensee Event Report 2009-001-00, "Late Entry into Technical Specification Condition associated with Reactor Coolant System Leakage Characterization" resulting in a condition prohibited by Technical Specifications The enclosed Licensee Event Report (LER) is being submitted in accordance with 10 CFR 50.73, "Licensee event report system," paragraph (a)(2)(i)(B) as a condition prohibited by the plant's Technical Specifications (TS). The LER involves the late entry of TS 3.4.13, "RCS Operational Leakage," Condition B on June 26,2009.
There are no regulatory commitments contained in this letter. Should you have any questions concerning this submittal, please contact Mr. David Gudger, Regulatory Assurance Manager, at (815) 406-2800.
Respectfully, bJ~~
Daniel J. Enright Site Vice President Byron Station
Enclosure:
LER Number 2009-001-00
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 08/31/2010 (9-2007)
, the NRC may digits/characters for each block) not conduct or sponsor, and a person is not required to respond to, the information collection.
- 13. PAGE Byron Station, Unit 2 05000455 1 of 4
- 4. TITLE Late Entry into Technical Specification Condition associated with Reactor Coolant System Leakage Characterization resulting in a condition prohibited by Technical Specifications
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED FACILITY NAME DOCKET NUMBER MONTH DAY YEAR YEAR 1SEQUENTIAL I REV MONTH DAY YEAR N/A NUMBER NO.
FACILITY NAME DOCKET NUMBER 06 24 2009 2009 001 00 08 24 2009
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply) 1 D
20.2201 (b)
D 20.2203(a)(3)(i)
D 50.73(a)(2)(i)(C)
D 50.73(a)(2)(vii)
D 20.2201(d)
D 20.2203(a)(3)(ii)
D 50.73(a)(2)(ii)(A)
D 50.73(a)(2)(viii)(A)
D 20.2203(a)(1)
D 20.2203(a)(4)
D 50.73(a)(2)(ii)(B)
D 50.73(a)(2)(viii)(B)
D 20.2203(a)(2)(i)
D 50.36(c)(1 )(i)(A)
D 50.73(a)(2)(iii)
D 50.73(a)(2)(ix)(A)
- 10. POWER LEVEL D
20.2203(a)(2)(ii)
D 50.36(c)(1 )(ii)(A)
D 50.73(a)(2)(iv)(A)
D 50.73(a)(2)(x)
D 20.2203(a)(2)(iii)
D 50.36(c)(2)
D 50.73(a)(2)(v)(A)
D 73.71 (a)(4) 100%
D 20.2203(a)(2)(iv)
D 50.46(a)(3)(ii)
D 50.73(a)(2)(v)(B)
D 73.71 (a)(5)
D 20.2203(a)(2)(v)
D 50.73(a)(2)(i)(A)
D 50.73(a)(2)(v)(C)
D OTHER D
20.2203(a)(2)(vi)
I:8J 50.73(a)(2)(i)(B)
D 50.73(a)(2)(v)(D)
Specify in Abstract below or in 2009 001 00 Shift Management was immediately notified. After a review of the appropriate Technical Specifications (TS), Shift Management concluded this small leak was considered RCS "identified" leakage and not RCS "pressure boundary" leakage. No TS actions were necessary for this condition since the TS 3.4.13, "RCS Operational Leakage", limit on RCS "identified" leakage is less than 10 gpm and the existing identified leakage for Unit 2 at the time was 0.0467 gpm. This conclusion of RCS "identified" leakage was based on the determination that the leak was through an isolable fault in the RCS pressure boundary and this fault was isolated from the RCS via the closed 2PS9350B.
2PS9350B was fully qualified, operable and no degraded condition existed with the valve's operation at the time.
Although a small amount of leakby was likely occurring past the closed isolation valve it was still considered isolated from the RCS. The condition was placed into the Corrective Action Program and appropriate administrative controls were initiated to ensure the 2PS9350B remained closed.
On June 26, 2009, at 7:00 am, the site was informed by the NRC Senior Resident Inspector that they disagreed with our characterization of the leak as RCS "identified" leakage and that it should be instead considered RCS "pressure boundary" leakage. The NRC's basis for this position was that the leak was not isolated because some leakby was occurring past the isolation valve's seat out through the fault.
In light of the NRC's position, the site re-visited the basis for the original conclusion by Shift Management and concluded the original decision to characterize the leakage as RCS "identified" leakage was appropriate. The NRC was notified accordingly. At approximately 4 pm, the NRC again reiterated that they disagreed with the site's conclusion and that they believed the leakage is RCS "pressure boundary" leakage and the appropriate TS needed to be followed.
The licensee acknowledged the NRC position and immediately entered TS 3.4.13 Condition B on Unit 2 for exceeding the RCS "pressure boundary" leakage limit at 4:30 pm on June 26, 2009. Condition B requires Unit 2 to be placed in Mode 3 in six hours and Mode 5 in 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />. In addition, an expedited repair effort of the PS line had been initiated earlier in the day. The repair to the line was successfully performed and tested by 8:07 pm, and TS 3.4.13 Condition B was exited prior to beginning the required ramp down to Mode 3. Note that during the repair when the line was drained and 2PS9350B was used as an isolation point, a small trickle of water came out which tapered quickly down to less than discernable.
Applying the NRC position to this condition, a TS non-compliance existed in that TS 3.4.13 Condition B should have been entered on June 24, 2009, at approximately 1:00 pm. Unit 2 not being in Mode 3 by 7:00 pm on June 24, 2009, is a condition prohibited by TS and reportable to the NRC in accordance with 10 CFR 50.73(a)(2)(i)(B).
C.
Cause of the Event
Through the application of TS and TS Bases, Shift Management characterized an RCS leakage situation as identified leakage.
The NRC subsequently indicated this leakage characterization was incorrect. The NRC's position is being further evaluated and resolution will be provided in a supplement to this LEA.
D.
Safety Significance
2009 001 00 This event had very low safety significance due to the extremely small nature of the leakage past the seat of the closed isolation valve for approximately 55 hours6.365741e-4 days <br />0.0153 hours <br />9.093915e-5 weeks <br />2.09275e-5 months <br /> before Technical Specification 3.4.13 Condition B was entered.
A postulated worst-case leakage from a complete severance of the 3/8 inch PS line, and assuming the isolation valve was stuck full open, would still be well within the RCS system makeup system's capability. The reactor could be shutdown and cooled in an orderly manner.
E.
Corrective Actions
The leak has been repaired. The NRC's position is being evaluated, additional actions will be determined, pending these interactions.
F.
Previous Occurrences
None NRC FORM 36M (9-2007)
PRiNTED ON RECYCLED PAPER