05000499/LER-2010-003, Regarding Containment Purge in Operation When Not Permitted by Technical Specifications
| ML102070104 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 07/19/2010 |
| From: | Peter L South Texas |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| NOC-AE-10002574 LER 10-003-00 | |
| Download: ML102070104 (7) | |
| 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 |
| 4992010003R00 - NRC Website | |
text
Nuclear Operating Company South Texas Project Electric Generating Station P.O Box 289 Wadsworth. Texas 77483 July 19, 2010 NOC-AE-10002574 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 2 Docket No. STN 50-499 Licensee Event Report 2-2010-003: Containment Purge in Operation When Not Permitted By Technical Specifications Pursuant to 10 CFR 50.73, the STP Nuclear Operating Company (STPNOC) submits the attached Unit 2 Licensee Event Report (LER) 2-2010-003 to address an incident in which supplemental containment purge was initiated contrary to Technical Specification requirements. This condition is considered reportable under 10 CFR 50.73(a)(2)(i)(B) as a condition not allowed by Technical Specifications.
This event did not have an adverse effect on the health and safety of the public.
There are no commitments contained in this LER. The STP Corrective Action Program controls processing of corrective actions.
If there are any questions on this submittal, please contact either P. L. Walker at (361) 972-8392 or me at (361) 972-7158.
/L. W. Peter Plant General Manager PLW
Attachment:
LER2-2010-003:
Containment Purge in Operation When Not Permitted By Technical Specifications STI: 32703369
NOC-AE-1 0002574 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 John Ragan Catherine Callaway Jim von Suskil NRG South Texas LP A. H. Gutterman, Esquire Morgan, Lewis & Bockius LLP Mohan Thadani U. S. Nuclear Regulatory Commission Kevin Polio Richard Pena 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
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.
- 3. PAGE South Texas Unit 2 05000499 1 OF 5
- 4. TITLE Containment Purqe in ODeration When Not Permitted by Technical Specifications
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED MONTH DAY YEAR YEAR SEQUENTIAL REV MONTH DAY YEAR FACILITY NAME DOCKET NUMBER NUMBER NO.
N/A N/A FACILITY NAME DOCKET NUMBER 05 22 10 2010 - 003 -
0 07 19 2010 N/A N/A D. OPERATING MODE
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR§: (Check all that apply) 0 20.2201(b)
[I 20.2203(a)(3)(i)
[I 50.73(a)(2)(i)(C)
El 50.73(a)(2)(vii) 0E 20.2201(d)
El 20.2203(a)(3)(ii)
[I 50.73(a)(2)(ii)(A)
El 50.73(a)(2)(viii)(A)
[o 20.2203(a)(1)
[I 20.2203(a)(4)
[I 50.73(a)(2)(ii)(B)
El 50.73(a)(2)(viii)(B)
Dl 20.2203(a)(2)(i)
El 50.36(c)(1)(i)(A)
[I 50.73(a)(2)(iii)
El 50.73(a)(2)(ix)(A)
- 10. POWER LEVEL El 20.2203(a)(2)(ii)
El 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)
[E 73.71(a)(4)
El 20.2203(a)(2)(iv)
El 50.46(a)(3)(ii)
[I 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)
[I 50.73(a)(2)(v)(C)
El OTHER El 20.2203(a)(2)(vi) x 50.73(a)(2)(i)(B)
[: 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 361-972-8392CAUSE OMPONENT MANU-REPORTABLE
CAUSE
SYSTEM COMPONENT MANU-REPORTABLE FACTURER TO EPIX FACTURER TO EPIX NA
- 14. SUPPLEMENTAL REPORT EXPECTED
- 15. EXPECTED MONTH DAY YEAR SUBMISSION El 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 May 22, 2010, the Unit 2 Supplemental Containment Purge Subsystem was used to reduce containment pressure. This is a routine operation used to maintain containment pressure consistent with Technical Specification requirements.
A surveillance test was in progress that required one of the two Solid State Protection System (SSPS) containment isolation automatic actuation logic channels be taken out of service. With one logic channel out of service, containment purge valves are required to be kept closed.
Required actions for an inoperable ESFAS instrumentation channel or interlock are shown in Technical Specification Table 3.3-3.
With fewer than the minimum of two automatic actuation logic channels operable, operation may continue only if the containment purge supply and exhaust valves are maintained closed. Opening the containment purge valves when only one SSPS train is operable is not permitted under Technical Specifications. This condition is considered reportable under 10 CFR 50.73(a)(2)(i)(B) as a condition not allowed by the Technical Specifications.
Initiation of supplementary containment purge with an inoperable SSPS train/channel resulted from inadequate personnel communications and a deficient procedure.
Conduct of Operations requirements will be revised to ensure adequate communications and assignment of responsibilities, and procedures will be revised to enhance control over containment purge initiation.
There were no personnel injuries, no offsite radiological releases, and no damage to other safety-related equipment. Because containment purge valves could still be closed on a signal from the operable logic channel, this is not a safety system functional failure.
NRC FORM 366 (9-2007)
(If more space is required, use additional copies of SUMMARY OF THE EVENT On May 22, 2010, preparations were made to perform a surveillance test of the Unit 2 Solid State Protection System (SSPS) Logic Train R.
This procedure verifies the Logic Train R SSPS Automatic Trip and Automatic Actuation Logic output functions by simulating input combinations in conjunction with each possible interlock. Placing Logic Train R in test mode prevents it from automatically actuating various features.
At 1517 hours0.0176 days <br />0.421 hours <br />0.00251 weeks <br />5.772185e-4 months <br />, the SSPS Input Error Inhibit Switch was placed in the "inhibit" position in accordance with the surveillance test procedure. An inoperable logic train requires entry in several actions as described in Technical Specification Table 3.3-3, including a requirement that containment purge valves be closed.
At approximately 1540 hours0.0178 days <br />0.428 hours <br />0.00255 weeks <br />5.8597e-4 months <br />, a reactor operator observed an indicator showing reactor containment pressure was near its alarm setpoint. At 1542 hours0.0178 days <br />0.428 hours <br />0.00255 weeks <br />5.86731e-4 months <br />, the reactor operator initiated supplemental purge of reactor containment for pressure control. The primary reactor operator was informed of the purge activity and noted it in the Unit 2 Control Room logbook.
At 1554 hours0.018 days <br />0.432 hours <br />0.00257 weeks <br />5.91297e-4 months <br />, containment pressure had been satisfactorily regulated and supplementary purge was secured.
The primary reactor operator was informed of the conclusion of purge activity and noted it in the Unit 2 Control Room logbook. Logic Train R was restored at 1601 hours0.0185 days <br />0.445 hours <br />0.00265 weeks <br />6.091805e-4 months <br />.
During the shift change at approximately 1800 hours0.0208 days <br />0.5 hours <br />0.00298 weeks <br />6.849e-4 months <br />, the oncoming Shift Manager reviewed the Control Room logbook and recognized the period of concurrent supplementary purge operation and logic train test mode condition as being a violation of Technical Specification requirements.
Note that the Train S actuation of purge valve closure was still available during the surveillance. There were no failures that would have prevented Train S from closing the purge valves. Therefore, this is not a safety system functional failure.
(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 NRC Form 366A) (17) reactor operator observed that pressure indication showed the need to relieve pressure through actuation of the Supplementary Containment Purge Subsystem.
Purge was initiated without informing crew supervision.
The log was updated to note initiation of containment purge, but the entry for beginning the surveillance procedure was not read.
B.
In addition, the surveillance procedure does not include a prohibition against performing a supplemental containment purge with the logic train out of service for testing.
IV. CORRECTIVE ACTIONS
A.
Remedial Actions:
No remedial actions are required.
B.
Compensatory Actions:
Control room staff is briefed when the unit enters a Technical Specification Limiting Condition of Operation.
C.
Recurrence Control:
Control room staff communications will be enhanced by the following changes:
" Revise Conduct of Operations to define control room crew standards for communications regarding Technical Specification requirements.
Revise Conduct of Operations to establish expectations and standards for making and updating logbook entries.
" Revise supplementary containment purge procedure to specify notification of control room staff supervision before initiating containment purge.
In addition, the supplemental containment purge procedure will be revised to prohibit purging containment atmosphere when a logic train is out of service.
These actions are expected to be completed by September 21, 2010.
V. PREVIOUS SIMILAR EVENTS
Control room logs were reviewed for instances of containment building purges while surveillance procedures that place restrictions on containment purge activities were in progress.
No similar violations of Technical Specification Table 3.3-3 Action 18 were found.
VI. ADDITIONAL INFORMATION
Investigation did not identify an organizational weakness or adverse condition beyond the circumstances of this event.