ML20065T314
| ML20065T314 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 12/17/1990 |
| From: | Fairtile M Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20065T305 | List: |
| References | |
| NUDOCS 9012280037 | |
| Download: ML20065T314 (7) | |
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SAFETY: EVALUATION BY Tg,0FFICE_0F_ NUCLEAR _ REACTOR M GULATION 4
SUPPORTING AMENOMENT-NO._127__'TO TACILITY 0"LTM!G LICENSE NO._ DPR-28
.VEP.MONT YANKEE NUCLEAR POWER CORPORATION VERMONT YANKEE NUCLEAR POWER STATION DJCKETN0_._50-271
_ INTRODUCTION By letters dated April 27 and June 23,1989,.-the Vermont Yankee Nuclear Power Corporation (VYNPC or the licensee) requested an amendment to Facility Operating 1
-License No. DPR-28 for the Vermont Yankee Nuclear Power Station (VYNPS or the L
plant). The proposed amendment would change.the expiration date of Fccility i
Operating-License No. DPR-28 from December 11, 2007 to March 21, 2012.
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BACKGROUNJD The licensee's' letter of-April 27 1989 requested an expiration date based on l
40 years from issuance of the fulIpower operating license that was issued on l
February 28, 1973., However, the plant received a fuel load and low-power j.
operating license dated March 21, 1972. The staff pointed out in discussions L
-with the licensee that the operating period started _on March 21, 1972, not
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' February 28, 1973. The licensee, by letter dated June 23, 1989, revised their l
application-to change-the operating 111 cense expiration date to 40 years from.
l March 21, 1972.;
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n The staff issued:a-notice of " Proposed Ho Significant Hazards Consideration L
Determination"intheFederalRegister(54'FR31120) dated. July 26, 1989.
1 This notice allows for public comment or a request for a hearing-from "any.
_ person whose~ interest may be affected by this-proceeding." By letter dated August'22~, 1989 the State of Vermont filed aEpetition for leave to intervene.
and requend an evidentiary hearing. An Atomic Safety and Licensing Board was established to consider-this matter and-the State of Vermont was admitted into.
the proceeding as an'intervenor pursuant'to 10 CFR 62.714 on January 26,-1990.
The _ staff issued an Environmental Assessment (EA) dated June 27,1990(55FR26313).
,as required by'10 CFR 51'.21 and 51.22, in which it concluded thatsthe. July 1972 LFinal Environmental Statement for VYNPS remains valid and pursuant to 10 CFR-51.31 an' environmental impact statement need not be prepared for this action.-
DISCUSS _IO_N 4
Sect' ion 103.c:of the Atomic Energy Act of 1954-provides that a license is to be-issued for a specified period not exceeding 40 years. The Code of Federal Regulations in'10 CFR 50.51' specifies that each license will be issued for a fixed period of time.not to exceed 40 years from date of issuance. Also, 10 CFR 50.56'and 10 CFR-50.57 allow.the issuance of an operating license
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-p-1 pursuant to 10 CFR 50.51 after the construction of the facility has been substantially completed, in conformity with the con;truction permit and when other provisions specifitd in 10 CFR E0.57 are met. The currently licenstd term for the VYNpS is 40 years, conmencing with the issuance of the construction permit on Deteciber 11, 1907. Accounting for the time that was r(quired for plant construction, this represents an effective operating license term of less than 30 years. Consistent with Section 103.c of the 1.tomic Energy Act end Sections !0.51, 50.56 and 50.57 of the Comission's regulations, the licenste, by its atplication of April 27 and June 23, 1989, seeks extension of the operating license term from the date of operating license issuance, namely 40 years from March 21, 1972. This action would extend the period of operation to the full 40 years providtd by the Atonic Energy Act and the Code of Federal Pegulations.
EVALUATION The licensee's request for extension of the operating license is bated on the f act thet a 40 year service lif e was considered during the design end construction of the plant.
Although this c;oes not mean that some corrponents will not wear out during the plant lifetime, design features were incorporated which maximire the inspectability of structures, systems and equipment.
Surveillance and maintenance practice! which were implemented in accordance with the ASME code end the facility Technical Specifications provide assurance that any crexpected degradation in plant equipment will be identified and corrected. The plant's mechanical and electrical touipment, reactor vessel integrity and structures are evaluated in the following stparate sections of this report, a.
Pechanical Equ_ipment The Final Safety Analysis peport for VYNpS as approved by HRC's Safety Evalut. tion Report, has evalut.ted the adequacy of safety-related mechanical systems, equipment, and components for A0 years of plant operation. Where a specific dtsign lifetime is specified in the Safety Analy(ErpY) at 801 sis Report, it is at least 40 years (e.g., 32 Effective Full power Years capacity factor).
However, the plant has opettted over the past 18 years at a 701 capacity f actor; thus, this couipment has received only a fraction of its design life to date.
Although some mechanical equipment and components might wear out or need replacement during the plant operating lifetime, existing surveillance and maintenano programs are sufficient to maintain or determine the need f or replacement of saf ety-related components, periodic inservice inspection and testing requirements have been incorporated into procedures to provide the added assurence that any unanticipated degradation in systens or equipet-nt will be identified ar.d corrected in a timely manner.
The licensee has demonttrated a willingness to replace degraded safety-related comperents or to add new components or systems as recently demonstrated by the proposed replacon.ent of large diameter feedwater check valves and the uninterruptible power supply to the low-pressure coolant system injection valves and the voluntary conmitrent to ado a wetwell hardened vent path.
These are corritments nade in 1990.
3 Therefore, the staff concludes that safety-related mechenical systems, equipment and components will not lose their intended safety function over a 40 year operating lifetime.
b.
Electrical _ Equ_ipgent The staff has also evaluated the safety implications of extending the operating licenst on safety-related electrical systems and equipment. This evaluation considered the licensee's review of extended service life impacts on equipment and integrated dose qualifications in response to 10 CFR 50.49, the environmental qualification rule.
For safety related electrical equipment within the scope of 10 CFR $0.49, aging reviews have been conducted by the licensee so as to establish a qualified life for the equipment.
For this t;quipment, the staff believes that the licensee has controls in place to cnsure that required surveillance and maintenance are performed.
These are described in the YYNPC Environmental Qualification Program and procedures. The current YYHPC Equipment Qualification (EQ) program is in complience with 10 CFR 50.49. The extension of the operating license is not affected by any unresolved E0 issues.
As discussed in the preceding section en Mechanical Equipment the licensee has substantially upgraded safety related electrical systems during 1990.
This is demonstrated by the commitment to reroute power cables in the post-accident monitoring system, added battery surveillances and the previously mentioned Uninterruptible Power Supply which is both a mechanical and electrical system.
Based on this evaluation, the staff con, udes that electrical systems design electricalequipmentselectionandapplication,andenvironmentalqualificatIon of electrical equipment either considered the effects of a 40 year operational lifetime or will not be affected by a 40 year operationel lifetime, c.
Reactor Vessel Intearity Reactor Vessel (RV) integrity is ensured by having controlled the design of the RV and then limiting its operation within conservative bound:,,
in addition to these design and operating considerations, there are two surveillanco prograns in place to periodically monitor RV integrity.
The vessel was designed for a 40 year life; however, the Technical Speci-fications (TS) limit operation to 32 effective full-power years (EFPY).
Since initial licensing in March 1972 to the present (September 1990) thc vessel has operated at about 72% of this time interval, resulting in 0.72 x 18.5 calendar years = 13.3 EFPY of operation.
Assuming the 4 year and 3 month license extention is added to future operation and assuming e conservative future operating rate of 801, the resultant EFPY of operation is 0.8 x 21.5 = 17.P. The interval from the present time until March 2012 is 21.5 yects. The sum of past and assumed future operation would then be 13.3 + 17.2 = 30.5 EFPY of operation. Therefora, two conservatism! are
4-rresent: fit st, the RV was designed for a 40 year full power life but restricted to a 32 year operating life by the TS end second, it will not exceed a probable operating life of 30.5 years.
The two surveillance programs, mentioned above, and prescribed by the TS are the Structural Integrity and Operability Testing and the Pressure and Temperature Limitations programs.
This letter program includes the RV irradiation surveillance specimen program.
The Structural Integrity program includes the Inservice Inspection (ISI) and Inservice Test (!$T) programs of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code - Section XI implementation of these programs is mandated by 10 CFP. 50.55a " Codes and Standards."
Tht-Staff has previously evaluated both the 151 and IST programs and found then acceptabic.
The staff ias reviewed the licensee's pressure and teinperature limitations th a Safety tvaluation issued as part of License Amendment No.120, dated trril 17, 1990. This Safety Evaluation also included the staff's evaluation of the lictrsee's response to our Generic Letter 88-11. "NRC Position en Radiation E;nbrittlement of Reactor Vessel Materials." The staff concluded that the proposed pressure and tempert.ture (P/T) limits for the reactor coolant system, of which the reactor vessel is an integral component, for l
heatup, cooldown, leak test and operation are valid through 32 EFPY es the limits conferu to the requirements of Appendices G and H of 10 CFR Part
- 50. The licensee also satisfied Gtneric Letter 88-11 guidance by using the methods of Regulatory Guide 1.99, Revision 2, in a conservative manner to calculate the adjusted reference temperature.
Therefore, the staff found the proposed P/T limits acceptable for incorporation into the VYNPS TS.
The staff concludes, based on the above evolut.tions, that reactor vessel integrity is ensured through March 21, 2012.
d.
St_ructu_res The structures at the VYNPS are heavy duty industrial tuildings or unique structures, such as the drywell and wetwell (torus), constructed of reinforced concrete, structural steel or a combination of both. These structures were initially founded and crected with good construction practices and the construction was audited by NRC inspections.
Industrial experience with such materials indicates that a service life in excess of 40 years is bttainable.
Plant walkdowns of the containment structures ere performed regularly so that any observed degradation can be corrected.
In particular a containment intterated leak rate test (ILRT), that verifies the leak tightness of the containment throughout its service life, is performed at least three times every 10 years.
The staff concludes, based on the above evaluation, that the original construction standards and ongoing surveillance programs should ensure that the safety-related plant structures will previde satisfactory service for et least a 40 year operaticne.1 lifetime.
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Maintenance and_ Surveillance pro g,s Surveillance programs that ensure functional operability of all safety-t related structures, components and systems are mandated by the VYNpS TechnicalSpecifications(TS). These TS are part of the plant's operating license and have been approved by the NRC, as are all subsequent c1anges i
to the TS. These surveillances ensure operability indefinitely.
The scope of the surveillance requirements in the TS is delineated in 10 CFR 50.36(c)(3).
The licensee has in place a maintenance program for all safety-related structures, components and systems.
This program has been inspected by-an NRC Maintenance Inspection Team which issued an Inspection Report (50-271/89-90) dated June 2, 1989.
In terms of overall plant serformance as related to maintenance, the Report stated:
" General and control of maintenance work areas, equipnent, tools, plant 1ousekeeping l
and materiel were observed to be well suited for accomplishing maintenance work during the refueling outage. Observation of maintenance work in progress and review of completed we'k indicated that maintenance is being performed by stillful, knowledgettle and competent plant personnel and contractors.
Maintenance work is w o l supervised and indicates that the stendard for i
the quality of work is high. This standard is reflected in a relatively low rework rate for maintenance and repairs on plant systems. The good housekeeping and knowledgeable maintenance personnel are strengths in their maintenance pro 0rsm
- 1 The Report found some minor problems in the maintenance program that have been satisfactorily resolved in a follow up-inspection report (50-271/90-12) dated November 21, 1990.
The licensee has in 31 ace an extensive Quality Assurance program to support and verify tie Surveillance and Maintenance programs.
The NRC in itsmostrecentSystematic/sssessmentofLicenseeperformance(SALP)
Report (50 271/88 99) dated March 7. 1990 stated:
"The SAlp Doard assessment noted a continued licensee commitment to the safe operation of the Vermont Yankee Nuclear-Power Station. During the atsessment period, few challenges to personnel and safety systems occurred, indicative of a managementand the pla transient rate. Overall. performance was-involvement in plant operations that was comprehensive and 'strongly oriented toward nuclear safety. Technical-competence and management-strengths were most notable in the functional areas of plant operations, maintenance and surveillance, engineering and technical support, and erergency preparedness."
This March 7, 1990 Report gave the licensee the NRC's highest rating in the
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functional areas of Maintenance / Surveillance and Safety Assessment / Quality Verification.
Based on the TS and observed licensee performance in the areas of surveil-lance and maintenance, the staff believes that future operation will be at the same-level as past operation, thus enturing proper maintenance and surveilitnce of safety-related structures, components and systems for the full 40 years of operation requested by the licensee,
6-FINAL K0 SIGNIFICthT HAZARDS CONS 10 ERAT 10!i DETERMINATION The licensee's request for emendment to the operating license for Vermont Yankee, including a proposed determination by the staff of no significant ha:ards consideration, was no+ iced in the Federal Register on July 26,19P9, (54 FR 31120).
In a letter dated May 9, 1990, the State of Vermont requested the staff to reconsider and withdraw its retice of the proposed determination of no significant hazards consideration.
The staff responded by letter dated June 20, 1990, stating that it had re-reviewed its original determination and confirmed that the licensee's amendment recuest meets the criterie of 10 CFR 50.92; therefore, there was no reason to withdraw the notice.
The staff has considered the comments of the State of Vermont and the State of Vermont's contention admitted into this proceeding. The staff continues to believe that the analysis published in the Federal Reoister on July 26, 1989, (54 FR 31120) remains valid. 1hc staff, thiWoM,ToiM3es that the proposed amendment involves no significant ha:ards consideration.
SUPMARY OF FINDINGS The llRC staff concluded in the Environmental Assessocnt that the enrual radiological effects during the additional years of operation that would be authorized by the proposed license amendment are not more than were previously estimated in the Final Environmental Statement, and are acceptable.
The steff concludes from its censiderations of the design, operation, mainte-nance and survtillance of the safety-related structures, conponents and systems at the VYNPS that en extension of the operating license to a 40 year service life is consistent with the plant's final Safety Analysis Report (i.e., the M ign basis), and NRC Safety Evaluation Reports.
Based on this, the staff turthre concluc s that there is reasonable assurancc that the plant will be able a cont'nue te operate safely for the additional period autheri:cd by this license amenoret. The plant is operated in compliance with the Commission's regulathns ano d., opere+ing license dated February 28, 1973, in summary, the NRC staff finds that extension of the operating license for the Vermont Yankee Nuclear power Station to allow for a 40 year service life is consistent with the final Environmental Statement and the Safety Evaluation Reports for the plant and that these documents remain valid for the proposed action.
EhY1RONMEtlTAL_ CONSIDERATION A Notice of issuance of Environmental Assessmcnt and Finding of tio Significant Irpact relating to the proposed extension of the facility Operating License termint. tion dates for the VYNpS was published in the Federal Reaister on June 27, 1990(55FR2E313).
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7 CONCLUSIONS The staff has revic nd and evaluated the licensee's request for changing the expiration date of v.cility Operating 1.icense DPR.28 for the Verrhont Yankee Nuclear Power Station.
Bascd on the considerations discussed in this safety evaluation, the staff concludes that:
(1) This amendment will not (a) significantly increase the probability or consequences of accidents previously evaluated, (b) create the possibility of a new or different accident from any accident previously evaluated, or (c) significantly reduce a margin of safety; and therefore, the amendment does not involve significant hazards considerations; (2) there is reasonable assurance that the health and sefety of the public will not be endangered by operation in the proposed inanner, and (3) such activities will be conducted in compliance with the Corrist. ion's regulations, and the issuance of the amendment will not be inimical to the corr.on defense and security or to the health and safety of the public.
Dated:
December 17, 1990 Principal Contributor: Morton B. Fairtile
AMENDMENT 110.127 10 DPR-28 VERMONT YAliKEE NUCLEAR POWER STATION DATED ecember 17. 199 D
01STRIBUTION:
Dii~cTKTili 50-271k~'
PDl 3 Reading I
S. Varga l
E. -Gnemstr Q(kwn n!a n M. Rushbrook H. fairtile R. Wessman OGC - 15 GIB Dennis Hagan - FNBB 3206 E. Jordan - MNBB 3701 B. Gritnes - 9 A3 G. Hill (4)-P137 J. Calvo - 11 F23 Wanda Jones - MNBB - 7103 C.Y. Cheng - 9 H15 L. Marsh - 9 H3 C. Bagchi - 8 B22 S. Newberry - 7 E12 F. Rosa - 8 D20 ACRS(10)-P135 GPA/PA - 2 G5 OC/LTMB - MNBB J. Johnson, Region 1 9enn,j 1..
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