05000498/LER-2009-002, Regarding Main Steam Isolation Valve Blocked from Closing
| ML093280588 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 11/16/2009 |
| From: | Peter L South Texas |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| NOC-AE-09002485 LER 09-002-00 | |
| Download: ML093280588 (6) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 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 |
| 4982009002R00 - NRC Website | |
text
Nuclear Operating Company South Texas Proect Electnc Generating Station PO. Box 289 Wdsworth, Texas 77483
- - v v
16 November, 2009 NOC-AE-09002485 File No.: G25 10 CFR 50.73 U. S. Nuclear Regulatory Commission Attention: Document Control Desk One White Flint North 11555 Rockville Pike Rockville, MD 20852-2738 South Texas Project Unit 1 Docket No. STN 50-498 Licensee Event Report 1-2009-002 Main Steam Isolation Valve Blocked from Closing Pursuant to 10 CFR 50.73, the STP Nuclear Operating Company (STPNOC) submits the attached Unit 1 Licensee Event Report 1-09-002 to address an incident in which maintenance activities blocked a Main Steam Isolation Valve (MSIV) from fully closing. This condition is reportable under 10 CFR 50.73(a)(2)(i)(B).
This event did not have an adverse effect on the health and safety of the public.
There are no commitments contained in this Licensee Event Report. Corrective actions will be processed in accordance with the STP Corrective Action Program.
If there are any questions on this submittal, please contact either P. L. Walker at (361) 972-8392 or me at (361) 972-7158.
Louis eter Plant General Manager PLW Attachment: LER 1-2009-002, Main Steam Isolation Valve Blocked from Closing STI: 32565968
NOC-AE-09002485 Page 2 of 2 cc:
(paper copy)
(electronic copy)
Regional Administrator, Region IV U. S. Nuclear Regulatory Commission 612 East Lamar Blvd., Suite 400 Arlington, Texas 76011-8064 Mohan C. Thadani Senior Project manager U.S. Nuclear Regulatory Commission One White flint North (MS 8B 1A) 11555 Rockville Pike, Rockville, MD 20852 Senior Resident Inspector U. S. Nuclear Regulatory Commission P. 0. Box 289, Mail Code: MN1 16 Wadsworth, TX 77483 C. M. Canady
'City of Austin Electric Utility Department 721 Barton Springs Road Austin, TX 78704 Kevin Howell Catherine Callaway Jim von Suskil NRG South Texas LP A. H. Gutterman, Esquire Morgan, Lewis & Bockius LLP Mohan Thadani U. S. Nuclear Regulatory Commission J. J. Nesrsta R. K. Temple Kevin Polio E. Alarcon City Public Service C. Mele City of Austin Jon C. Wood Cox Smith Matthews Richard A. Ratliff Texas Department of Health Services Alice Rogers Texas Department of Health Services
INRC 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.
- 3. PAGE South Texas Unit 1 05000498 1 OF 4
- 4. TITLE Main Steam Isolation Valve Blocked from Closina
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED SEQUENTIAL REV FACILITY NAME DOCKET NUMBER MONTH DAY YEAR YEAR NUBR N.MONTH DAY YEAR N/NA NUMBER NO.
N/A N/A FACILITY NAME DOCKET NUMBER 09 17 09 2009
- - 002 -
0 11 16 2009 N/A N/A
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR§: (Check all that apply)
El 20.2201(b)
El 20.2203(a)(3)(i)
El 50.73(a)(2)(i)(C)
El 50.73(a)(2)(vii) 1 El 20.2201(d)
El 20.2203(a)(3)(ii)
El 50.73(a)(2)(ii)(A)
El 50.73(a)(2)(viii)(A)
El 20.2203(a)(1)
El 20.2203(a)(4)
[I 50.73(a)(2)(ii)(B)
El 50.73(a)(2)(viii)(B)
El 20.2203(a)(2)(i)
[E 50.36(c)(1)(i)(A)
El 50.73(a)(2)(iii)
El 50.73(a)(2)(ix)(A)
- 10. POWER LEVEL El 20.2203(a)(2)(ii)
[3 50.36(c)(1)(ii)(A)
El 50.73(a)(2)(iv)(A)
El 50.73(a)(2)(x)
[I 20.2203(a)(2)(iii)
El 50.36(c)(2)
El 50.73(a)(2)(v)(A)
El 73.71(a)(4)
[1 20.2203(a)(2)(iv)
[I 50.46(a)(3)(ii)
El 50.73(a)(2)(v)(B)
El 73.71(a)(5) 100%
El 20.2203(a)(2)(v)
El 50.73(a)(2)(i)(A)
El 50.73(a)(2)(v)(C)
[E OTHER El 20.2203(a)(2)(vi) x 50.73(a)(2)(i)(B)
El 50.73(a)(2)(v)(D)
Specify in Abstract below
- 12. LICENSEE CONTACT FOR THIS LER NAME TELEPHONE NUMBER (Include Area Code)
Philip L. Walker, Staff Licensing Engineer 1
361-972-8392MANU-REPORTABLE MANU-REPORTABLE
CAUSE
SYSTEM COMPONENT MAU EOTBE
CAUSE
SYSTEM COMPONENT MN-RPRAL FACTURER TO EPIX FACTURER TO EPIX NAj______
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- 14. SUPPLEMENTAL REPORT EXPECTED
- 15. EXPECTED MONTH DAY YEAR SUBMISSION [E YES (If yes, complete 15. EXPECTED SUBMISSION DATE) x NO DATE ABSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines)
On September 17, 2009, Unit 1 Main Steam Isolation Valve (MSIV) 1 D (MS-FSV-7444) was discovered to be inoperable due to restricted movement that kept it from being closed completely. Erection of a wooden deck work platform around MSIV 1 D began on September 14 with decking that was later found to interfere with valve movement. Operability was restored at 14:57 on September 17, 2009, when the scaffolding was modified to remove the interference.
Technical Specification 3.7.1.5 requires that each MSIV be operable in Modes 1, 2, and 3. If one MSIV is inoperable but open, power operation may continue provided that operability is restored within four hours, or the requirements of the Configuration Risk Management Program are met. Otherwise, the unit is to be in at least hot standby within six hours. Because the MSIV was inoperable longer than allowed under the Technical Specifications without taking the appropriate action, this event is reportable under 10 CFR 50.73(a)(2)(i)(B).
The root cause of the event was inadequate procedures for scaffold installation. The procedures did not ensure an adequate review of the impact of the scaffold installation on operation of the plant.
Procedures are to be revised to improve control over installation of scaffolding.
Only MSIV 1D was affected by this condition. There were no personnel injuries, no offsite radiological releases, and no damage to other safety-related equipment.
NRC FORM 366 (9-2007)
(If more space is required, use additional copies of SUMMARY OF THE EVENT On September 14, 2009, construction of a wooden deck work platform was begun around MSIV 1D to support implementation of a design change. Construction was completed on September 16,. The deck was below the actuator flange and on all four sides of MSIV 1 D, a position that would have prevented MSIV 1D from performing its design function of closing on demand. This condition was observed by a Reactor Operator performing his rounds on
- - September 17, 2009, and reported to Engineering and Operations management.
Subsequent measurement confirmed that interference between the wooden deck work platform and the valve actuator would prevent valve closure.
Following confirmation of the interference, action was initiated to dismantle the platform. The platform was removed at 14:57 on September 17 and MSIV 1D was restored to operable status. The estimated duration of MSIV 1 D inoperability is 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.
Because MSIV 1D was inoperable longer than the Technical Specification allowed outage time, the condition was reported to the NRC under 10 CFR 50.73(a)(2)(i)(B).
All scaffolds in STP Unit 1 and Unit 2 were subsequently inspected, and no other instance of interference was found.
E.
METHOD OF DISCOVERY
This condition was identified by a Reactor Operator making his normal rounds of the Isolation Valve Cubicle.
I1. EVENT-DRIVEN INFORMATION A.
SAFETY SYSTEMS THAT RESPONDED No safety systems were required to respond during this event.
(If more space is required, use additional copies of (If more space is required, use additional copies of NRC Form 366A) (17)
Engineering or Operations to identify and document limitations, restrictions, requirements, or considerations near or around equipment important to plant operations. Additionally, no input is required by these departments to periodically verify that previously approved non-standard scaffold and/or decking sketches are still valid.
" The procedure for erection and use of temporary scaffolding does not contain requirements or attributes with the depth and rigor needed for non-standard scaffold and/or decking installation in areas containing plant equipment important to plant operation. Such work warrants written guidance to ensure adequate job quality and work control.
The pre-job brief is not required to address application of scaffold installation limitations and restrictions consistent with functional requirements of adjacent equipment.
" The scaffold permit process lacks guidance when addressing special applications such as decks and platforms.
The guidance should include restrictions on use while at power, limitations for adjacent equipment operation, and cautions for various plant operational modes.
IV. CORRECTIVE ACTION
Revise procedures to establish the process and requirements, including pre-job briefs and the permitting process, for installation of scaffolding and other structures in critical areas of the plant.
Expected Completion:
02/12/2010
V. PREVIOUS SIMILAR EVENTS
There have been no similar events associated with scaffolding at the South Texas Project. Also, there have been no recent instances at the South Texas Project of maintenance activities having an adverse impact on unrelated aspects of the operating plant.
VI. ADDITIONAL INFORMATION
None.