ML110030675
| ML110030675 | |
| Person / Time | |
|---|---|
| Site: | Byron  |
| Issue date: | 01/02/2011 |
| From: | Quigley B - No Known Affiliation |
| To: | Borchardt R NRC/EDO |
| References | |
| G20110002, OEDO-2011-0002, 2.206 | |
| Download: ML110030675 (5) | |
Text
EDO Principal Correspondence Control FROM:
DUE: 02/02/11 EDO CONTROL: G20110002 DOC DT: 01/02/11 FINAL REPLY:
Barry Quigley
- Rockford, Illinois TO:
Borchardt, EDO FOR SIGNATURE OF :
- GRN CRC NO:
- Leeds, NRR DESC:
ROUTING:
2.206 - Exelon Nuclear: Byron Unit 2 (EDATS: OEDO-2011-0002)
DATE: 01/03/11 Borchardt Weber Virgilio Ash Muessle OGC/GC Satorius, RIII
- Burns, OGC
,Kotzalas, OEDO ASSIGNED TO:
NRR CONTACT:
Leeds SPECIAL INSTRUCTIONS OR REMARKS:
-.1c~okI bc)-mcI 7--N t"U0 -D
EDATS Number: OEDO-2011-0002 Source: OEDO Geea Ifraio Assigned To: NRR OEDO Due Date: 2/2/2011 11:00 PM Other Assignees:
SECY Due Date: NONE
Subject:
2.206 - Exelon Nuclear: Byron Unit 2
==
Description:==
CC Routing: Region l l; OGC; Tanya. Mensah@nrc.gov; Catherine. Scott~nrc.gov ADAMS Accession Numbers - Incoming: NONE Response/Package: NONE Ohr Inomtn I.1 i1 Cross Reference Number: G20110002 Related Task:
File Routing: EDATS Staff Initiated: NO Recurring Item: NO Agency Lesson Learned: NO OEDO Monthly Report Item: NO Prcs Informaion Action Type: 2.206 Review Signature Level: NRR Approval Level: No Approval Required OEDO Concurrence: NO OCM Concurrence: NO OCA Concurrence: NO Special Instructions:
Priority: Medium Sensitivity: Sensitive Related Urgency: NO Documen Infraion Originator Name: Barry Quigley Originating Organization: Citizens Addressee: R. W. Borchardt, EDO
-Incoming Task Received: Letter Date of Incoming: 1/2/2011 Document Received by OEDO Date: 1/3/2011 Date Response Requested by Originator: NONE Page 1 of l
"d January 2, 2011
Subject:
2.206 Petition for Byron Unit 2 (Docket 50-455)
Dear Mr. Borchardt,
This is a request under 10 CFR 2.206 for enforcement action regarding untimely corrective actions and failure to follow procedures at Exelon Nuclear's Byron Unit 2.
Background
High temperatures downstream of a Byron Unit 2 Pressurizer safety valve (2RY8010A) were noted in June of last year. High temperature alarms occurred over the summer but the tailpiece alarm has been in solid since late October'. In September 12 had begun questioning when the valve would be replaced but was unable to get a clear answer. As I looked into the issue further, I became concerned with the safety valve operability. On 10/24/10, I wrote IR 1130085, Concerns with 2RY8010A Operability. The key points of the IR were:
The Byron pressurizer safety valve installation is referred to as a heated loop seal with a temperature of approximately 300'F. Any seat leakage must be replaced by hot fluid from the pressurizer; this could result in loop seal temperatures higher than tested. If the safety valve then lifted, the hotter loop seal could take longer to purge due to choked flow of the flashing hot water. This could delay the time before the safety valve was effective in reducing RCS pressure.
Safety valves are known to experience setpoint changes with changes in temperature.
The leaking steam could cause internal temperature changes and result in valve lift pressures outside the allowable band.
I was assigned to perform the Operability Evaluation for IR 1130085 using procedure OP-AA-108-115 (which closely parallels NRC RIS 2005-020).
The evaluation was completed on 10/29/10 under EC 381932 and addressed the concerns raised in IR 1130085. I selected a corrective action due date of 11/29/10 based on guidance in OP-AA-108-115 which states the corrective action dates should be commensurate with the safety significance of the component.
For the following reasons, I concluded that the safety valves were very important and a short date was appropriate:
- 1. One measure of the importance of the pressurizer safety valves is their role in maintaining the RCS safety limit of 2735 psig.
- 2. All three safety valves are required to function to maintain RCS pressure below the safety limit, i.e., there is no single failure "allowance".
- 3. Another indicator for the appropriate timeliness is the LCO duration. TS 3.4.10 requires that an inoperable safety valve be restored to operable within 15 minutes or the unit shutdown.
- 4. A review of pressurizer safety valve LERs since 1980 found no examples where a leaking safety valve was challenged to perform its overpressure function while installed.
lThe 2RY801OA leakage is currently somewhat steady at 0.10 gpm.
2 Petitioner is on the Design Engineering staff and held an SRO license for 14 years.
EDO -- G20110002
Therefore there is no valid operating experience regarding the capability of a safety valve to fulfill its Tech Spec function while leaking.
- 5. In some cases safety valves (at other plants) that leaked during a cycle were found out of tolerance when bench tested, in other cases the valves lifted within specification. This uncertainty supports minimizing the "exposure time" to a degraded safety valve.
The due date of 11/29/10 was originally not accepted by management; only after I refused to sign the Op Eval was the date accepted.
In mid-November, I learned that the due date for 2RY8010Areplacement had been changed to 2/7/11, in part based on OTDM 2010-10 (Operational and Technical Decision Making).
On 11/23/10, I wrote IR 1144179, Disagree with 2RY80IOA Op Eval CA Extension.
In the IR I stated:
My signature on the op eval was contingent on a repair date of 11/29/10. Although there is no real process, I will withdraw my signature3 on the Op Eval at midnight on 11/29/10.
Currently Exelon's plan for resolution of my concerns is by using the concept of "Differing Professional Opinion". I lack faith that this informal process has the necessary horsepower to shutdown a 1200 MWe unit.
Since completion of the Op Eval, additional concerns4 have been identified:
- 1. The possible presence of two-phase leakage may alter the valve lift pressure since the flow characteristics in the huddling chamber will not be as designed. Currently it is thought that such leakage could cause the valve to lift early, outside the Tech Spec allowable band.
- 2. The continuous operation of the pressurizer backup heaters on unit 2 increases the pressurizer vapor space hydrogen concentration.
The presence of increased non-condensable gasses reduces heat transfer and could be preventing reformation of the loop seal.
Potential Consequences
- 1.
2RY8010A fails to open as designed. Concern would be failure of the RCS pressure boundary, increased RCS leakage or extensive analyses required prior to restart.
- 2.
2RY8010A opens early when RCS pressure rises following a turbine trip. The normal valve blowdown could reduce RCS pressure enough to cause a Safety Injection. A water-solid pressurizer could then result.
3 As of 1/2/11, the operability section of IR 1144179 has not been completed, contrary to'the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> procedural requirement to do so.
4 These new concerns have not been entered in CAP consistent with the unwritten management expectation that Issue Reports not be written until assurances can be provided to Operations that the components are operable.
Page 2 of 3
Request ofNRC
- 1.
Issue the appropriate level of violation for failure to comply with 10 CFR 50 Appendix B Criterion XVI as it applies to 2RY801 OA leakage.
- 2.
Issue the appropriate level of violation for failure to document operability for IR 1144179.
My contact information is:
Barry Quigley 3512 Louisiana Rd Rockford, IL QPIF@AOL.COM 815-397-3392 (h) 815-222-4745 (c) 815-406-2005 (w)
/s/
Barry Quigley Page 3 of 3