ML041620454
| ML041620454 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 06/09/2004 |
| From: | O'Brien D State of VT, Dept of Public Service |
| To: | Richard Ennis NRC/NRR/DLPM |
| Shared Package | |
| ML042330452 | List: |
| References | |
| TAC MC3406, Y020040125 | |
| Download: ML041620454 (6) | |
Text
Original Due Date: 08/31/2004 Ticket Number: 020040125 Document Date: 06/09/2004 NRR Received Date: 06/10/2004 From:
TACs:
MC3406 David O'Brien To:
- YELLOW ***
Richard Ennis For Signature of:
==
Description:==
Vermont Yankee Nuclear Power Station Assigned To:
DLPM Routing: Dyer Borchardt Sheron Case NRR Mailroom
Contact:
MARSH, LEDYARD (TAD) E Special Instructions:
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Internce: http://wwv.slaie.vt.us/psd STATE OF VERMONT DEPARTMENT OF PUBLIC SERVICE June 9, 2004 RE:
Vermont Yankee Nuclear Power Station License No. DPR-28 (Docket No. 50-271)
Technical Specification Proposed Change No. 262 Alternate Source Term - State of Vermont Comments Richard Ennis, Project Manager U.S. Nuclear Regulatory Commission Washingron, D.C., 2OS55
Dear Mr. Ennis,
The state of Vermont is asked to comment on Vermont Yankee's alternate source term (AST) proposal. We believe the AST proposal should not be approved without modifications for the following reasons:
- 1.
The standby liquid control (SLC) system does not appear to meet the single failure criteria appropriate for a system used to mitigate the consequences of a design basis accident ("an engineered safety feature system").
- 2.
The main steam isolation valve (MSIV) alternate leakage treatment (ALT) pathway does not appear to meet the quality standards appropriate for a system used to mitigate the consequences of a design basis accident ("an engineered safety feature system').
- 3.
There is no reason to reduce safety margins for Vermonters by doubling the amount of allowed leakage from MSIV's from the leakage levels Vermont Yankee has met for the past 32 years.
Back gound On August 8, 2003, we asked the NRC a series of questions regarding Vermont Yankee's AST proposal. The NRC staff responded on December 16, 2003. In that letter, NRC defers a number of responses by stating it "will address the adequacy of the licensee's request in our final SE [safety evaluation)". On May 12 and 13, 2004, we were provided J;\\VYPowerUprate\\NRC !tems\\AST commntsel.1pd
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- V Richard Ennis, Project Manager June 9, 2004 by email information on the NRC's proposed final SE of the SLC system single failure and AST quality assurance design.
SLC System Single Failure As part of the AST proposal, the function of the Vernnont Yankee standby liquid control (SLC) system would be modified. In its original design, the SLC system was provided as a backup system to provide negative reactivity to the reactor core in the event of beyond-design-basis events. As such, the SLC system was an auxiliary supporting system. For AST, the SLC function is changed to provide pH control for the suppression pool after design basis accidents. Therefore, the SLC becomes an engineered safety feature (ESF) system.
The SLC system is not filly redundant. Portions of the SLO piping are not redundant, and two non-redundant active check valves are located on the containment penetration for the system.
Regarding single failure, Vermont Yankee's ESF design criteria is stated in Section 1.5.6 (4) of its Final Safety Analysis Report:
Essential safety actions shall be carried out by redundant and independent equipment so that no single failure of an active component can prevent required actions.
The current NRC single failure criteria is stated in 10 CFR 50, Appendix A as:.
Single failure. A single failure means an occurrence which results in the loss of capability of a component to perform its intended safety functions.
Multiple failures resulting from a single occurrence are considered to be a single failure. Fluid and electric systems are considered to be designed against an assumed single failure if neither (1) a single failure of any-active component (assuming passive components function properly) nor (2) a single failure of a passive component (assuming active components function properly), results in a loss of the capability of the system to perform its safety functions.
NRC claims that it is'acceptable for an appfication not to meet the single failure criteria if acceptable quality and reliability of the non-redundant component can be shown. It's claims are based on guidance contained in Regulatory Guide 1.53, "Application of the IAVYPowerUprate\\NRC lrermsAST com.'ents I.wpd 2
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l Richard Ennis, Project Manager June 9, 2004 Single-Failure Criterion to Nuclear Power Plants Protection Systems." December 16 letter, Response 3(b).
We disagree with this interpretation of single failure for four reasons. First, it is contrary both to the plain statement of Vennont Yankee's design and licensing basis and the NRC's regulation. Second, it is contrary in practice to Vermont Yankee's design of engineered safety feature system. We do not know of other cases in which Vermont Yankee ESF systems were licensed with non-redundant active components. Third, if NRC is changing Vermnont Yankee's licensing basis based on new interpretations, it should not grant this change piecemeal. Section C.5.1.4 of Regulatory Guide 1.183 (quoted below) states that current-day licensing standards will be used for the AST review:
S 1.4 Applicability ofPrior Licensing Basis The NRC staff considers the implementartion of an ASTto be a significant change to the design basis ofthefacility that is voluntarly initiated by the licensee. In order to issue a license amendm ent authorizing the use of an AST and the TEDE dose criteria, the NRC staff must make a currentfinding of compliance with regulations applicable to the amendment. The characteristics of the ASTs and the revised dose calculational methodology may be incompatible with many ofthe analysis assumptions and methods currently rej7ected in the faciliy's design basis analyses. The NRCsaff nmayfind that new or unreviewed issues are created by a parficular site-specific implementation of the AST.
warranting review ofstaffpositionx approved subsequent to the initial Issuance ofthe license. This is not considered a bac)kf as defined by 10 CPR 50.109, "Backisting/"
However, prior design bases thar are unrelated to the use of the AST, or are unaffected by the AST, may continue as thefaciliy's design basis. Licensees should ensure that analysis assumptions and methods are compatible with the ASTs and the TEDE criteria, We believe that, if any part of new licensing bases are used, the complete applicable new licensing basis should be used. If NRC is applying a less-stringent, current-day single failure criteria, it should invoke all applicable current-day licensing bases, including but not limited to single passive failure design and current seismic design requirements.'
Fourth, Vermont Yankee has not demonstrated the non-redundant check valves meet the NRC's current-day requirement for quality and reliability. Similar check valves have failed to open in five other similar applications in the industry. Entergy February 25, 2004 letter to NRC, Response to RAI No. 4(a)(2).
Therefore, we believe that, in order to approve the AST proposal, NRC should require the new Vennont Yankee ESF SLC system to meet the single failure criterion.
We note that Entergy, in its February 25, 2004 Response to Request for Additional Informazion, Response to RAI No. I (b), states it does not meet current-day seismic design requirements but reverts to its earlier, less stringent original licensing basis.
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LV Richard Ennis, Project Man3ger June 9, 2004 MS1V Alternate Leakage Treatment (ALT) Pathway In conjunction with, but unrelated to, its AST proposal, Vermont Yankee requests to double its allowable individual MSIV leakage of 31 standard cubic feet per hour as part of an alternate leakage treatment pathway. The ALT pathway includes piping and valves to the main condenser which were neither designed nor purchased to safety-related system requirements. Because the intended use of the ALT pathway is to mitigate the consequences of a design basis accident, it is an engineered safety feature. NRC letter of December 16, 2003, Response 2(a).
Vermont Yankee has performed analysis demonstrating the ALT piping and.valves, including the condenser, are seismically rugged. However, this analysis is neither the same evaluation for ESF systems in Vermont Yankee's current licensing basis, nor is it the seismic analysis that would be required for ESF systems under NRC's current-day seismic requirements. In addition, since the ALT piping and values, including the condenser, were not purchased under an 10 C.F.R. 50, Appendix B quality assurance program, confidence in current seismic analysis is uncertain since material properties and weld techniques are uncertain.
The issues of seismic and quality assurance design of the ALT pathway were questioned in our August 8, 2003 letter. NRC's response was that the issues would be addressed in the final SE. NRC letter of December 16, 2003, Responses 2(e) and 2(f). In an email of May 13, 2004, NRC identified its intent to approve the seismic and quality assurance portions of the ALT pathway based on footnotes and exceptions from two Standard Review Plan (SRP) Revision 2 Drafts from 1996 (SRP 3.2.1, "Seismic Classification",
and SRP 3.2.2, "System Quality Group Classification').
We disagree with NRC's evaluation for three reasons. First, we do not believe unapproved, draft SRPs should be used as the basis for approval of Vermont Yankee's proposed ALT. Why are the SRP's still in draft form from 1996? What is NRC's policy on using draft information for its review standard? We note that these draft SRP's are neither referred to in the Regulatory Standard for Power Uprate (RS-00l) nor available in the NRC's SRP collection on its website. Second, we-believe that Vermont Yankee's original ESF licensing basis should be invoked for the ESF ALT pathway. This would include Seismic Class I design and analysis and purchase to a 10 C.F.R. 50, Appendix B, quality assurance program. Third, we see no reason to allow Vermont Yankee twice as much leakage through its MSIV's. In its AST amendment request of July 31, 2003, it states that maintaining the current litnit would cause unnecessary maintenance. However; Vermont Yankee has been able to maintain these MSIV's to the current limit for the last 32 years. Doubling the allowable leakage would mean potentially exposing Vermonters IAVYPowertipra:e\\NRC ltems\\AST comrnentsl.wpd 4
S Richard Ennis, Project Manager June 9, 2004 to twice as much radioactive leakage from MSIV's in the event of a design basis loss-of-coolant accident. Based on past successful maintenance history, exposing Vennonters to this increased potential is unnecessary and undesirable.
We do not believe the request for increased MSIV leakage should be granted. If the increase MSIV leakage is granted, we would like NRC to provide a presentation of the increased risks to Vemnonters from the increased MSIV leakage and the issues concerning whether Vermonters should be subject to this increased risk.
Conclusion We welcome the opportunity to provide these comments and look forward to resolving these issues in a satisfactory manner. If you have questions about these items, please call me at 802-828-2321, or Mr. William Sherman of my staff at 802-828-3349.
Sincerely, David O'Brien. Commissioner State Liaison Officer cc:
J. Thayer, Entergy Sen. Patrick Leahy Sen. James Jeffords Rep. Bernard Sanders I:W'YPowerUprate\\NRC 1tcms\\AST comments I.wpd 5