ML20106F935

Application for Amend to License NPF-30,revising Tech Specs to Extend Period for Completion of Containment Vessel Tendon Surveillance by 6 Months.Fee Paid

ML20106F935
Person / Time
Site:	Callaway
Issue date:	02/12/1985
From:	Schnell D UNION ELECTRIC CO.
To:	Harold Denton Office of Nuclear Reactor Regulation
Shared Package
ML20106F938	List: ML20106F935 ML20106F947
References
ULNRC-1037, NUDOCS 8502140156
Download: ML20106F935 (7)

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+ g 1901 Grotiot Street St. Louis Donald F.Schnell February 12, 1985 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D.C. 20555 ULNRC- 1037

Dear Mr. Denton:

DOCKET NUMBER 50-483 CALLAWAY PLANT, UNIT 1 REVISION TO TECHNICAL SPECIFICATION 4.6.1.6.1, SURVEILLANCE OF CONTAINMENT VESSEL TENDONS Union Electric Company herewith transmits three (e) original and forty (40) conformed copies of an application for amendment to Facility Operating License No. NPF-30 for Callaway Plant, Unit 1.

This application requests that the Callaway Technical Specifications, Appendix A to the Operating License, be revised to extend the period for completion of the containment vessel tendon surveillances required by Specification 4.6.1.6.1.

Deferral of the Callaway surveillance is required-to allow Union Electric's inspection contractor, INRYCO, Inc., to assist Alabama Power Company in evaluating anomalies recently found in the containment post tensioning system of the Parley-Unit 2 plant.

Without INRYCO's services, the outage at-Farley would be unnecessarily extended. The enclosures to this letter include a safety evaluation of the requested change,-. consideration of significant hazards, and a proposed revision to Page 3/4 6-8'of the Technical Specifications. These enclosures document Union Electric's position that the requested amendment does not present a significant hazard.

The requested change involves an additional 6 mo.nths in the'due date of the initial one year tendon surveillance and a resultant step change of 6 months in the subsequent surveillance dates. Our need date for approval of this amendment request is- -

April.5, 1985,-based on the current date. scheduled for completion of-the subject' surveillance. ' Enclosed is a check for the $150.00 application fee-required by 10CFR170.21.

Very truly yours, K ON 8 Donald F. Schnell DFS/DS/bjp

Enclosures:

1-Safety Evaluation \

2-Significant Hazard Consideration CP 3-Marked Specification Page 3/4 6-8 t% O' Moihng Addrest P.O Box 149, St. Louis MO 63166 g pM -

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s STATE OF MISSOURI )

)' SS CITY OF ST. LOUIS )

Donald F. Schnell, of lawful age, being first duly sworn

- upon oath says that-he is Vice President-Nuclear and an officer of Union' Electric Company; that he has read the foregoing document and

-knows the content thereof; that he has executed the same for and on behalf of said company with full power and authority to do so; and that the facts therein stated are true and correct to the best of his knowledge, information and belief.

By _ _

Donald F. Schnell Vice President Nuclear

. SUBSCRIBED and sworn,to before me this /8 day of 198f BARBARA P

$f/w F NOTARY PUBLIC, STATE OF MISSOURI MY COMMISS1ON EXPIRES APRIL 22,1985 ST. LOUIS COUNTY n-

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cc: ' ' Gerald Charnoff, Esq.

Shaw, Pittman, Potts & Trowbridge 1800 M. Street, N.W.

Washington, D.C. 20036

, LNicholas A. Petrick

, Executive Director ~

SNUPPS 5 Choke Cherry Road

[ Rockville,. Maryland 20850 John H. Neisler Callaway Resident Office

.U.S._ Nuclear Regulatory Commission RRil Steedman, Missouri 65077 2

William Forney Division of Projects and 1 Resident Programs, Chief, Section lA

, ~U.S. Nuclear Regulatory Commission  ;

Region III

799 Roosevelt Road Glen Ellyn, Illinois 60137 Bruce Little Callaway Resident' Office U.S. Nuclear Regulatory Commission RRill '

Steedman, Missouri 65077 Jan'Stevens

. . Office of Nuclear Reactor Regulation

, :U.S.JNuclear Regulatory Commission Mail Stop P-316 e- 7920 Norfolk Avenue

-Bethesda, MD: 20014 Ron Kucera, Deputy Director Department of Natural Resources

P.O. Box 1761

. Jefferson City, Missouri _ 65102 P'

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Enclosure 1 to ULNRC-1037 SAFETY EVALUATION This amendment request revises the timing associated with Technical Specification Surveillance 4.6.1.6.1, by extending each

>ofEthe three containment vessel tendon surveillances six (6) cmonths. . This. extension is requested because the-services of .

>INRYCO,'the inspection contractor for. Union Electric and Alabama

-Power.Co., are needed to evaluate anomalies recently found at the

'Farley -1 Unit.2-plant. We have released INRYCO to Alabama Power Company.so-that'the outage associated with the Farley problem is not-unnecessarily extended. In support of this request, the ti following sections address the Callaway post tensioning system design conservatism, inspections of installation activities,

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field. anchor head materials, recent field inspection results, and expected.results of the' initial tendon surveillance based on Bechtel' experience.

' Design Conservatism The containment vessel' post tensioning system is designed to

. provide a minimum level of prestress of 1.2 times the design accident pressure at the end of the 40-year design life of the

, plant.- The prestressing tendons are initially stressed to provide an.even-higher level of prestress to allow for-time-dependent stress-losses which occur during the life of the plant.

As such, there is a significantly higher level of prestress.

1provided at the beginning of the design'11fe overrthat remaining after 40 years.

The Callaway post tensioning system was designe5 for an internal containment pressure:of 72 psig,:which is_ .2 times the

- .designLaccident pressure'of 60.psig. The'containmentswas subjected.to a' test' pressure of-69 psig during the. Containment Structural 1 Integrity Test (SIT) in January,_1984. In the event-of a main steam line break (the accidentiwhich yields the-maximum containment 1 pressure), pressure.is--' calculated to peak..at'48.1; psig.. This~provides-a: margin of 1.50,.25% higherLthan the required value.of 1.2. 'Takingfprestressing(. levels predicted to occur in six months-into account, the margin?becomes approximately;1.65..

It:should be noted_that,the 1.2 prestress factor is.provided only to maintain compression inlthe concrete shell during the

SIT. This level of prestress is-not required,1however, to maintain structural integrity. The containment'isfdesigned to'

/ remain elastic'atLinternal pressures of:approximately190 psig and

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"" it'can-be'shown-that the ultimate capacity is atlleastL120 psig.

' Inspections of Installation Activities ,

p During'the: period of'Februaryc1981 through October 1981, the-following audits, surveillances and inspections were completed

.' twhile; overseeing, installation ~of'the callaway containment. post tensioningssystem: e v

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_2-One Bechtel/UEQA Audit, Six UEQA Surveillances, One DIC/UEQA Audit, Three DIC/QA Surveillances, and Seven NRC Inspection Reports These reports document the performance of tendon button heading, tendon stressing, greasing, material storage, equipment calibration / qualification, QC inspection, and personnel qualification. All reports indicate satisfactory performance by INRYCO during installation of the Callaway post tensioning system.

Field Anchor Head Plate Materials Some of the problems encountered with containment post tensioning systems at other plants appear to be related to anchor head material manufactured and heat treated in the early 1970's.

A review of records provided for Callaway anchor heads by the material suppliers and heat treatment vendors showed the following:

Material Supplier Dates Copperweld 1980, 81 Tech. Steel & Alloy 1979, 80 Timken 1979, 80 Heat Treatment Vendors Specification Varco Heat Division MIL-H-6875-F Accurate Steel Treating PT 5.2.1 INRYCO FPM Heating Division PT 5.2.1 INRYCO It was determined that a different INRYCO heat treatment procedure was used for Callaway anchor heads (HT-101 had been used previously).* The material suppliers and heat treatment vendors employed for Callaway anchor heads are different than those involved with anchor heads which failed at other sites.

This reinforces our conclusion that tendons installed at Callaway continue to satisfy design requirements.

Recent Field Inspection Results On February 5, 1985 a visual inspection of the Callaway containment post tensioning system was conducted by personnel from Union Electric engineering and operations departments and Bechtel site engineering. The inspection involved looking for tendon grease cap deformation or abnormal grease leakage and excessive cracking around the tendon bearing plates. Further visual inspection cannot be performed without removing the grease cap, which requires the services of INRYCO.

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A close inspection was made of all 172 (86 tendons) inverted U and~100 (.0 5 tendons) reasonably accessible hoop anchorages. No

deformation, abnormal grease leakage or cracking was found.

An inspection of the remaining 170 (85 tendons) hoop and 60'-(30 tendons) horizontal dome anchorages was made with the aid of~ field' glasses. Tha deformation or abnormal grease leakage Was

-found.

Based on this inspection of all Callaway tendon anchorages, nct evidence was found to indicate a tendon failure or excessive stress in the' concrete.

Bechtel Initial Tendon Surveillance Experience

~Bechtel-has designed 14 containment buildings which employ post' tensioning systems-and for which the first year inspections

have been completed. Four of these units involved INRYCO, the

'same supplier-as was used at Callaway. All surveillances in the

.first year were acceptable.

Conclusion.

Based on the information above, the-proposed revision to Technical Specification 4.6.1.6;1 does not affect or endanger the thealth'and safety'of the general public and does not-involve an unreviewed' safety question.

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• Enclosure 2 to ULNRC-1037 SIGNIFICANT HAZARDS CONSIDERATIONS

-This amendment request revises the timing associated with Technical Specification Surveillance 4.6.1.6.1, by extending each of the three containment vessel tendon surveillances six (6) months. The Safety Evaluation, included as Enclosure 1 to this letter, provides Union. Electric's' bases for concluding that the Callaway Plantican be safely operated consistent with the revised surveillance schedule.

-The. Safety Evaluation addressed the design conservatism,

-inspections of installation activities, field anchor head materials, recent field' inspection results, and expected results

.from the initial inservice tendon surveillance for the Callaway post tensioning system. Based on this, a six month extension in the time for the detailed tendon surveillance will not

'significantly increase the probability of-tendon failure and will',.therefore, not increase the probability or consequences of any.previously analyzed accident.

Because'the proposed extension of the time for detailed l tendon surveillance will not impact tendon integrity, will not affect'the method and manner of plant operation and will not Laffect. components and: equipment important to-safe operation, the proposed amendment does .not create the possibility of a new and -

-different accident-from any previously evaluated.

.Because recentEfield. inspections _showed no evidence of

. tendon failure and'because containment prestress levels are not E<  : expected to decrease (by anyEsignificant degree in the proposed six month period of surveillance extension, this revision to the

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Technical Specifications will not significantly.' reduce,any' 3 margins'of safety.

Based on the foregoing analysis, the requested license amendment does not present a significant hazard.

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