ML20196K288
| ML20196K288 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 06/29/1999 |
| From: | Wanczyk R VERMONT YANKEE NUCLEAR POWER CORP. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20196K292 | List: |
| References | |
| BVY-99-83, NUDOCS 9907080261 | |
| Download: ML20196K288 (9) | |
Text
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p VEPMONT YANKEE
,, g NUCLEAR POWER CORPORATION 185 Old Ferry Road, Brattleboro, VT 05301 7002 (802) 257 5271 June 29,1999 BVY 99-83 U.S. Nuclear Regulatory Commission
' ATTN: Document Control Desk Washington, DC 20555
Subject:
Vermont Yankee Nuclear Power Station License No. DPR-28 (Docket No. 50-271)
Technical Specification Proposed Change No. 220 Main Steam Line Isolation Valve Leakane Pursuant to 10CFR50.90, Vermont Yankee (VY) hereby proposes to amend its Facility Operating
. License, DPR-28, by incorporating the attached proposed change into the VY Technical Specifications.
This submittal supersedes, in its entirety, Proposed Change No. 215 to VY Technical Specifications'.
This proposed change revises the leak rate requirements of Technical Specifications 3.7.A.4 and 4.7.A.4 for the main steam line isolation valves. Specifically, a total leakage rate allowable value for the sum of the four main steam lines is established that is equal to four times the current individual main steam line isolation valve leakage rate allowable value. The individual main steam line isolation valve leakage rate allowable value is revised to be one halt ~of the total leakage rate allowable value.
Analyses that assume main steam lint isolation valve leakage use either the cumulative leakage rate from the four main steam lines or the total primary containment leakage rate, versus using the individual valve or line leakage rate. The current restrictive individual valve leakage rate allowable value requirement of 11.5 scf/hr results in valve maintenance whenever a leak rate is even slightly above the specific acceptance criterion. Unless the cumulative main steam isolation valve leakage rate allowable value or the containment total leakage rate is challenged, this maintenance is unnecessary. The consequences of this unnecessary maintenance are increased worker exposure, increased outage duration, and possibly reduced component service life.
Attachment I to this letter contains supporting information and the safety assessment of the proposed change. Attachment 2 contains the determination of no significant hazards consideration. Attachment 3
' provides the mark-up version of the current Technical Specification page. Attachment 4 is the retyped Technical Specification page.
VY has reviewed the proposed Technical Specification change in accordance with 10CFR50.92 and concludes that the proposed change does not involve a significant hazards consideration.
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' better, VYNPC to USNRC, BVY 99-68," Technical Specification Proposed Change No. 215 - Removal of Main Steam Line Isclation Valve Leakage Specifications," dated May 6,1999.
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Pursuant to 10CFR50.91(b)(1), we have provided copy of this proposed change and the associated no significant hazards consideration to the appropriate State of Vermont representative.
VY has also determined that the proposed change satisfies the criteria for a categorical exclusion in accordance with 10CFR51.22(c)(9) and does not require an environmental review. Therefore, pursuant to 10CFR51.22(b), no environmental impact statement or environmental assessment needs to be prepared for this change.
We request that the Staffissue the subject license amendment no later than September 1999, in order to ensure implementation prior to the next scheduled refueling outage in October 1999.
If you have any questions on this transmittal, please contact Mr. Jim DeVincentis at (802) 258-4236.
Sincerely, VERMONT YANKEE NUCLEAR POWER CORPORATION C >h as Robert J. Wanc UU Director of Safe egulatory Affairs
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STATEOF VERMONT
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NOTAm i
Then per::onally appeared before me, Robert J. Wanczyk, who, being duly sworn, t
at ptJ3L.l$re[ar of.
Safety and Regulatory Affairs of Vermont Yankee Nuclear Power Corporation, that b ly orized t ecu$
and file the foregoing document in the name and on the behalf of Vennont Yankee Nu wer ation$
that the statements therein are true to the best of his knowledge and belief.
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Sally A. Sa6dstrum, Notary Public My Commission Expires February 10,2003 Attachments cc:
USNRC Region 1 Administrator USNRC Resident Inspector-VYNPS USNRC Project Manager - VYNPS Vermont Department of Public Service t
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YlittMONT YANhi.li NtTI.l'. Alt Pown'.it Colti'oltA'lloN Docket No. 50-271 BVY 99-83 i
Vennont Yankee Nuclear Power Station Propcsed Technical Specification Change No. 220 Main Steam Line Isolation Valve Leakage i
Supporting Information and Safety Assessment of Proposed Change i
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' BVY 99 83/ Attachment I / Page !
i INTRODUCTION Option B to 10CFR50 Appendix J was implemented at Vermont Yankee (VY) per Facility Operating License Amendment No.1525 With the advent of the Primary Containment Leak Rate Testing Program Plan (PCLRTP) created to implement Option B, the specific valve leak rate acceptance criteria of the Technical Specifications could be eliminated. He individual valve leak rates are components of the combined local leak rate as governed by Technical Specification 6.15, and control of the specific valve leak rate limits is provided by the PCLRTP that implements Technical Specification 6.15.
Therefore, the following paraphrased text "the leakage from any one isolation valve shall not exceed 5 percent of the allowable leak rate" was removed from the VY Technical Specifications 3.7.A.4 and 4.7.A.4 per Amendment No.152. However, the specific acceptance criteria for the main steam line isolation valves were retained.
Technical Specifications 3.7.A 4 and 4.7.A.4 contain main steam line isolation valve leakage acceptance criteria of 15.5 scf/hr at 44 psig (Pa) and 11.5 scf/hr at 24 psig (P ). The 15.5 scf/hr is equal to the t
calculated value of 0.05La (i.e., the pre-Amendment No.152 individual valve leakage rate limit discussed above, where La quals 0.8 wt%/ day [309.890 scf/hr]). The original and present Technical e
Specification surveillance requirement leakage acceptance criterion for the main steam line isolation valves is 11.5 scf/hr, when tested at a reduced pressure of 24 p,is (P ). During the post rule making t
implementation period for the original 10CFR50 Appendix J (circa 1972), VY requested relief from the requirement to test the main steam line isolation valves at 44 psig (Pa). In the Safety Evaluation dated August 19,19832, VY was granted relief to continue the testing of the main steam line isolation valves by pressurizing between the inboard and outboard valves at a reduced pressure of 24,,;(P ). VY will t
continue to utilize a reduced pressure test at 24 psig (P ). Pressurizing the main steam line isolation t
valves between the inboard and outboard valves.
The following analyses use main steam line isolation valve leakage as an assumption or input:
- 1. The design basis loss of coolant accident (DBA LOCA) analysis assumes a value for total primary containment leakage when determining the consequences. His assumption is validated by the testing in 10CFR50 Appendix J. VY adds the main steam line maximum pathway leakage rate to the results of the 10CFR50 Appendix J Types B and C tests summation for evaluation and for comparison to the 0.6La maximum and minimum combined leak rate acceptance criteria. Since the proposed changes are still bounded by 0.6La, there is no impact on the DBA LOCA analysis.
'2.
Control room radiological habitability was analyzed" by assuming each of the four main steam lines leaks at the Technical Specification limit (15.5 scf/hr) for the duration of the accident. The input value for the analysis is 4 X 15.5 scf/hr = 62 scf/hr. Since this proposed change adds a requirement
' Letter UShRC to VYNPC, NVY 98-24," Issuance of Amendment No.152 to Facility Operating License No. DPR-28, VYNPS (TAC No. M99264)," dated February 26,1998, 2 Lener USNRC to VYNPC, NVY 83-192," Exemption from Certain Requirements of Section 50.54(o) and Appendix J of 10 CFR 50," dated August 19,1983.
- Letter VYNPC to USNRC, FVY 81-8," Submittal ofInformation on NUREG 0737, Jtem III D.3.4: Control Room Habitability," dated January 12,1981.
d Letter USNRC to VYNPC, NVY 82 22," Safety Evaluation Report for Ill.D.3.4 Control Room Habitability Requirements (NUREG-0737)," dated February 24,1982.
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"" """" C""W Hunos BVY 99-83 / Attachm:nt I / Page 2 that does not allow the combined leakage from all four main steam lines to exceed 62 scf/hr, there is no impact on the input value for the control room radiological habitability analysis.
Therefore, with the removal of the individual valve limitation of 5 percent of the allowable leak rate, there is no basis for the individual main steam line isolation valve leak rate acceptance criteria.
Accordingly, VY proposes to:
- 1. Replace the existing Technical Specifications Limiting Condition for Operation (LCO) 3.7.A.4 that limits the leakage from any one main steam line isolation valve to 15.5 scf/hr at 44 psig (Pa) with an LCO that limits the total combined maximum pathway leakage rate from the four main steam lines to 62 scf/hr at 44 psig and limits the individual main steam line isolation valve leakage rate to one half of the total; i.e.,31 scf/hr at 44 psig. Including the total combined maximum pathway leakage rate ensures the validity of calculation assumptions.
- 2. Replace the existing Technical Specifications Surveillance Requirement 4.7.A.4 that requires testing to verify that the leakage from any one main steam line isolation valve does not exceed 11.5 scf/hr at 24 psig (P ) with a Surveillance Requirement to " verify leakage rate through each main steam line t
isolation valve is 5 23 scf/hr and that the combined maximum pathway leakage rate for all four main steam lines is 5 46 scf/hr when tested at 2 24 psig (P )." The change from "at 24 psig" to "at t
2 24 psig" is consistent with the BWR/4 Standard Technical Specifications and provides the 5
required testing flexibility recognizing that testing is potentially performed at prescures above 24 psig. The new limits provide additional margin for as-found testing, while remaining restrictive enough to require valve maintenance prior to severe degradation. This minimizes unnecessary valve maintenance that results in increased worker exposure and increased outage duration.
- 3. Continue to include the main steam line isolation valve leakage as a component of the Technical Specification 6.15 combined local leak rate acceptance criteria, adding the main steam line maximum pathway leakage rate results to the Types B and C tests summation for evaluation and for comparison to the 0.6La maximum and minimum combined leak rate acceptance enteria.
SAFETY ASSESSMENT The proposed change is not a safety concern and can be implemented without endangering the public health and safety because:
- 1. There are no safety related analyses that assume an individual main steam line leakage rate.
Therefore, revising the individual main steam line isolation valve leakage rate allowable value to be equal to one half of the total combined leakage rate allowable value to minimize unnecessary maintenance has no impact on safety.
- 2. The main control room radiological habitability analysis assumes leakage from the main steam lines at the proposed combined leakage allowable value. Herefore, this change is consistent with the analysis assumption.
- 3. He radiological consequences of the design basis loss of coolant accident are dependent upon containment leakage rates. He leakage rate limitations assumed in the safety analyses are not impacted by this change.
5 NUREG 1433, Stand-d Technical Specifications General Electric Plants, BWR/4, Revision 1, dated April 7, 1995
' **"" Y^""*" "t^" l"#8:n Courouri nos BVY 99-83 / Attachment I / Page 3 4.'
Main steam line isolation valve leakage is a component of the Technical Specification 6.15 combined local leak rate acceptance criteria and, as such, will continue to also be governed by that specification. There are no enanges proposed to Technical Specification 6.1S.
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vuou>st vma. Necu:.ui Powen conc <mmos Docket No. 50-271 BVY 99-83 I
Vermont Yankee Nuclear Power Station Proposed Technical Specification Change No. 220 Main Steam Line Isolation Valve Leakage.
Determination of No Significant Hazards Consideration i
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Vrnsum Y^sur. NerirAH l'owrn Coneon.uuW BVY 99-83 / Acachment 2 / Page 1 Pursuant to 10CFR500, Vermont Yankee (VY) has reviewed the proposed change and concludes that the ch.aige aocs not involve a significant hazards consideration since the proposed change satisfies the criteria in 10CFR50.92(c).
1.
He operation of Vermont Yankee Nuclear Power Station in accordance with the proposed amendment will not involve a sienificant increase in the probability or consecuences of an accident previously evaluated.
He proposed change does not involve a change to the plant design or operation. As a result, the proposed change does not affect any of the parameters or conditions that contribute to the initiation of any accidents previously evaluated. Thus, the proposed change cannot increase the probability of any accident previously evaluated.
The proposed change does not affect the leak-tight integrity of the containment structure that is oesigned to mitigate the consequences of a loss-of-coolant accident (LOCA). The primary containment must maintain functional integrity during and following the peak transient pressures and temperatures that result from any LOCA, thereby limiting fission product leakage following the accident. Because the proposed change does not alter any of the fission product leak rate assumptions used in the design basis LOCA analysis, the analyzed consequences of the Loss of Coolant Accident are not changed.
The control room radiological habitability analysis uses as an input assumption main steam line leakage rate et four times the current Technical Specifications limit. An allowable value for total main steam line leakeg,i rate equivalent to four times the current Technical Specifications limit for a single main steam line isolation valve is being added by this change. Thus, there is no effect on the main control room radiological habitability calculation.
i Based on the above VY has concluded that the proposed chenge will not result in a significant increase in the probability or consequences of any accident previously evaluated.
2.
De operation of Vermont Yankee Nuclear Power Station in accordance with the oronosed amendment will not create the nossibility of a new or different kind of accident from any accident previously evaluated.
The proposed change does not involve a change to the plant design or operation. As a result, the proposed change does not affect any parameters or conditions that could contribute to the initiation of any accident. The methods of performing the tests are not changed. No new accident modes are created.
No safety-related equipment or safety functions are altered as a result of this change. Restating the acceptance criteria while maintaining the assumptions of all affected calculations has no influence over nor does it contribute to, the possibility of a new or different kind of accident or malfunction from those previously evaluated.
Based on the above VY has concluded that the proposed change will not create the possibility of a new or different kind of accident from those previously evaluated.
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3 Vamovi nsur Nrcuan Pow ut Com'ournoN I
BVY 99 83 / Attachm:nt 2 / Page 2 3.
The operation of Vermont Yankee Nuclear Power Station in accordance with the prooosed amendment will not involve a sienificant reduction in a margin of safety.
Restating the acceptance criteria for the main steam line isolation valve leakage rate while maintaining the assumptions of all affected calculations does not impact the margin of safety, The 0.6La maximum and minimum pathway leakage rate acceptance criteria provide the previously analyzed margin of safety.
The testing method for determining the leak-tightness of the main steam line isolation valves has not changed. The leak rate test results are presently added to the Types B and C tests summation. The 0.6La maximum and minimum pathway leak rate acceptance criteria and the proposed Technical Specifications requirements provide assurance that component degradation does not impact the assumptions used to determine, nor provide a reduction in, the analyzed margin ofsafety.
Based on the above VY has concluded that the proposed change will not cause a significant reduction in a margin of safety.
Summary No Sienificant Hazards Consideration On the basis of the above, VY has determined that operation of the facility in accordance with the proposed change does not involve a significant hazards consideration as defined in 10CFR50.92(c), in that it: (1) does not involve a significant increase in the probability or consequences of an accident previously evaluated;(2) does not create the possibility of a new or different kind of accident from any accident previously evaluated; and (3) does not involve a significant reduction in a margin of safety.
In making this determination, Vermont Yankee has also reviewed the NRC examples of license amendments considered not likely to involve significant hazards considerations as provided in the final adoption of 10CFR50.92 poblished in the Federal Recister. Volume 51, No. 44, dated March 6,1986.
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