ML021420365
| ML021420365 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse, Summer  |
| Issue date: | 05/17/2002 |
| From: | Quigley B - No Known Affiliation |
| To: | Travers W NRC/EDO |
| References | |
| G20020302, TAC MB5113 | |
| Download: ML021420365 (4) | |
Text
EDO Principal Correspondence Control DUE: 06/11/02 Barry Quigley
- Travers, EDO FOR SIGNATURE OF :
- GRN Collins, NRR DESC:
ROUTING:
Inability to Detect Reactor Coolant Leakage DATE: 05/20/02 ASSIGNED TO:
NRR Travers Paperiello Kane Norry Craig Burns/Cyr CONTACT:
Collins SPECIAL INSTRUCTIONS OR REMARKS:
eibo-coi FROM:
CRC NO:
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EDO -- G20020302 nn nt-i -
nt-i u0 u0:-ua UI-CI-E DEPOT 24b(815)226-980 May 17, 2002 Dr. William Travers Executive Director for Operations Nuclear Regulatory Commission Washington, DC 20555-0001
Subject:
Inability to Detect RCS Leakage
Dear Dr. Travers,
Reactor Coolant System leaks at Davis Besse and V.C. Summer reinforce the need to detect RCS leakage. Not only does it make sense, it is also a legal requirement: "Means shall be provided for detecting and, to the extent practical, identifying the location of the source of the reactor coolant leakage."' The NRC's Regulatory Guide 1.45 is how this requirement is implemented and it provides very clear limits - detect a 1 gpm leak within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />. It also requires diverse methods of leak detection and that at least one of the means be seismically qualified. Accepted methods are by measuring the concentration of radioactivity in the containment atmosphere and measuring sump levels or flows. Critical to the success of the radioactivity method is that there be enough gaseous or particulate material in the RCS to register on the detector.
A review of NRC correspondence found several examples of problems with leak detection systems. For example, In recent years, plants have exhibited better fuel performance and improved chemistry resulting in less primary coolant radioactivity concentrations than was assumed when plants were originally licensed2 Does the above mean the NRC has been aware for the last 4 years that plants are operating outside the conditions of their licenses? Although later in the document the staff hints at upcoming generic activities, I have been unable to find results in the: public domain.
As a result of the VC Summer hot leg crack, "the NRC identified several generic issues to be addressed... 3) potential weaknesses in RCS leak detection systems")3.
Again, NRC has identified a generic issue with leak detection systems but is silent on actions to address it.
An evaluation of other publicly available data4 shows that all is not well with the capability to detect RCS leakage. Attached are summaries of 15 Licensee Event Reports where plants have been unable to meet the requirements of Regulatory Guide 1.45. In some cases, the failure was 10 CFR 50, Appendix A, Criterion 30 2 Safety Assessment of Region II Concerns Regarding Discrepancies of Containment Radiation Monitor Sensitivities at St Lucie and Turkey Point, June 24, 1998 MLO 11760038 3 NRC ]Information Notice 2000-17, Supplement 2, Crack in Weld Area of Reactor Coolant System Hot Leg Piping at V. C. Summer, Feb 28, 2001 4 It is unknown if the inability of the Byron and Braidwood plants to detect leakage consistent with Reg Guide 1.45 will be reported.
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17 02 O:20a OFFICE DEPOT 245 (815)226-9860 p.
2 due to ignorance of design requirements, in others because instruments lack the required sensitivity.
Considering the above examples, what reasonable assurances, based on objective data, can NRC provide the public that General Design Criterion 30 is being met?
An associated issue is a non-conservative assumption in most plants' Technical Specifications related to RCS leakage. A small amount of unidentified leakage is allowed, typically I gpm.
However, no pressure boundary leakage is allowed. The non-conservatism is that even though plants have unidentified leakage, licensees assume that it is not pressure boundary leakage. In other words, since it is unidentified how do they know it is not pressure boundary leakage?
Respectfully, Barry Quigley Senior Reactor Operator 3512 Louisiana Rd.
Rockford, IL 61108 815-397-8227 QP1F@AOL.COM cc: Dave Lochbaum, Union of Concerned Scientists
a, I-RCS Leak Detection LERs Plant Date Title - (Abbrev)
System Cause Corrective Action Accession Cook 4/1/99 RCS Leak Detection Sensitivity not Sump level/flow Inadequate original None substantial 9905050105 IAW Design Requirements Design Millstone 3 2/6/98 Rad Monitor Non-Conservative Particulate & Gaseous Historical Revised Setpoint 9803310291 Setpoint WRT RG 1.45 Byron 2/28/98 RCS Leak Detection Inop due to Sump level/flow Plugged floor drain not Requirements from 9803300441 Inadequate Communication properly communicated 3/15/97 not clear to workers Farley 10/7/97 RCS Leak Detection Inop due to Containment Fan Cooler Defective Procedure Throttled vlvs, revised 9710140260 Defective Procedure Condensate Flow (drain vlvs open vs procedure throttled)
Crystal River 7/30/97 Inadequate Engineering Eval Gaseous Historical personnel Revised Tech Spec 9806190155 Results in Loss of Diverse RCS error leakage detection Reisddeig /
odfed 98 3 40 9 LaSalle 5/12/97 Undrainable Areas Cause Increased Sump level/flow Original Design/Poor Revised design/Modified 9803040393 Delays in RCS Leak Detection equipment choice equipment Byron 3/15/97 Containment Drain System Sump level/flow Drains not installed per New design/Increased 9704220096 Clogged due to Debris design hydrolazing of drain lines North Anna 9/10/96 Seismic Concerns with Leak Particulate & Gaseous Historical Personnel Upgraded Piping to 9706180225 Detection Rad Monitors error Seismic Byron 8/15/96 Cmut Rad Monitor Setpoints do not Particulate & Gaseous Unknown Revised Setpoints 9609250180 meet design criteria McGuire 8/21/95 Failure to Comply with Tech Spec Particulate Monitor ran out of filter Repaired low filter paper 9509220160 for RCS Leak Detection paper alarm Callaway 7/8/94 Failure to Meet Tech Spec due to Gaseous Took Credit for non-Revised procedures to 9409220118 lack of knowledge of Commitment safety related display specify proper display S....
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