ML20074A457

Tech Spec Change Request 125 Permitting non-nuclear Heatup for Precritical Testing & Subsequent Operation Using Repaired Steam Generators

ML20074A457
Person / Time
Site:	Three Mile Island
Issue date:	05/09/1983
From:	GENERAL PUBLIC UTILITIES CORP.
To:
Shared Package
ML20074A448	List: ML20074A447 ML20074A453 ML20074A457
References
NUDOCS 8305130074
Download: ML20074A457 (7)

Text

O I. Technical Specification Change Recuest No. 125 The Licensee requests that the attached changed pages replace the following pages of the existing Technical Specifications.

Appenoix A T.S. 4.19 pages 4-80, 81, 82, 85 II. Reasons for the Change Recuest At the present time, Technical Specifications require in part successful completion of a periodic inservice inspection program of the steam generator tubes in order to confirm steam generator operability. T.S.

4.19 further indicates that where the inservice inspection program identifies tube defects, the tube in question will be removed from service by plugging.

The proposed change recognizes that for certain types of steam generator tube defects, other methods of repair may exist or may be developea to remove the defect from service. The change provides the flexibility to permit other repair methods to be used with the review and approval of the NRC Staff.

III. Safety Analysis Justifying Change No new method of repair is proposeo in this amendment. Any alternate repair methods proposea by the Licensee will recuire submission of a separate Safety Analysis for evaluation by the Staff. Thus, this change dces not involve an increase in the probability or consequences of accidents previously evaluated, does not introduce accidents other than those previously evaluateo, and does not recuce any safety margin.

IV. Amencment Classification (10CFR 170.22)

This change request is administrative in nature ano has no safety or environmental significance ano is therefore ccnsidered a Class II license amencment. A check in the amount of 1,200.00 will oe forwarded under separate cover.

V. Imolementation It is requesteo tnat the NRC act on this recuest by June 15, 1983.

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2. A seismic occurrence greater than the Operating Basis Earthquake.

3. A loss of coolant accident requiring actuation of ,the engineering safeguards, or

4. A major main steam line or feedwater line break.

4.19.4 Acceptance Criteria .

a. As useo in this Specification:

1. Imperfection means an exception to the dimensions, finish or contour of a tube from that required by fabrication i drawing or specifications. Eddy current testing indications below 20% of the nominal tube wall thickness, ~~

if detectable, may be considered as imperfections.

2.

Dearadation means service-induced cracking,

wastage, wear .

or general corrosion occurring on either insioe or outside -

of a tube. ,.

3. Dearaded Tube means a tube containing imperfections greater than or equal to 20% of the nominal wall thickness l .4 caused by degradation. .?fL

4. 5 Degradation means the percentage of the tube wall T-thickness affected or removed by degradation. N c -+:

! - 5. Defect means an imperfection of such severity that it ~$

l exceeds the repair limit. A tube containing a defect is .l defective. 1F

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6. Repair Limit means the imperfection depth at or beyond - ' 5 f2

which the degraded tube or portion of a tube shall be - pi repaired or removed from service because it may become -

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unserviceable prior to the next inspection. This limit is' fE l equal to 40% of the nominal tube wall thickness, unless S; J.;

l , 353 higher approvedlimitsby theare NRC.shown to be acceptable by analysis and ~ -

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7. Unserviceable describes the conoition of a tube if it I~

leaks or contains a defect large enough to effect its  ;..

I structural integrity in the event of an Operating Basis fj?

. Earthquake, a loss of coolant accident, or a steam line or ';17 feedwater line break as specified in 4.19.3.c, above. g{

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8. Tube Inspection means an inspection of the steam generator -

J tuoe from the bottom of the upper tubesheet completely to . " 'a the top of the lower tubesheet, except as permitted by Li 4.19.2.b.2, above. Jg; a:

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b. The steam generator shall be determined OPERABLE after ,

completing the corresponding actions (repair of all tubes exceeding the repair limit and all tubes containing throughwall cracks by plugging or by any other repair method shown to be acceptable by analysis or test, and approved by the NRC) requireo by Table 4.19.2.

4.19.5 Reports

a. Following the completion of each inservice inspection of steam generator tubes, the number of tubes repaired in each steam generator shall be reported to the NRC within 15 days after j completion of all repairs.

b. The completed results of the steam generator tube inservice ..

inspection shall be reported to the NRC within 3 months ~

following completion of the inspection. This report shall incluoe:

1. Number and extent of tubes inspected. J:

2. Location and percent of wall-thickness penetration for-  ;.

each indication of an imperfection. _~

3. Identification of tubes repaired ano method of repair._ l ,q

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c. Results of steam generator tube inspections which fall into ...

Category C-3 and require prompt notification of the NRC shall , = -: m .e -5 be reported pursuant to Specification 6.9.2 prior to . .

resumption of plant operation. The written followup of this -

report shall provide a description of investigations conducted ,

to determine cause of the tube degradation and corrective j[

measures taken to prevent recurrence. .

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The Surveillance Requirements for inspection of the steam generator tubes J) insure that the structural integrity of this portion of the RCS will be - - at 9

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. a' Table 4.19.2 ,

STEAM GENERATOR TU8E INSPECTION (2)

) ISI SAMPLE INSPECTION ll 2ND SAMPLE INSPECTION ll 3RD SAMPLE INSPECTIdi l l Sample Size l Result l Action Required _ll _ Result l Action Required ll Result l Action Required __l I I I ll l lI I l l A minimum of l C-1 l None ll N/A l N/A ll N/A l N/A l l S robes per I i ll l ll l l l S, G. (1) l I II I ll ~l I l l C-2 l Repair defective tubes and ll C-1 _l None ll N/_A l _ _ _

N/A _l l l l l tospect additional 2S tubes ll l _ll l l l l l In this S.G. ll C-2 l Repair defective ll_ C-1 l__ None l l l l ll l Luces and inspect ll l Repair defective l l l l ll l additional 45 ll C-2 l tubes l l l l ll l tubes in this S.G. ll l Perform action forl 1 l l ll l ll C-3 l C-3 resuit of I I I I Il_ l ll l _first sample l l l l ll l Perform action for ll l l l l l ll C-3 l C-3 result of firstll N/A l N/A l 1 l___ l ll l sample ll l l 1 l l ll Otner l ll l l l l C-3 l Inspect all tubes in this ll S.G. is l None ll N/A l N/A l l l l S.G. , repai r defective ll C-1 l tubes and inspect 2S tubes ll Other l ll l ll l l l Perform action for ll l l l l l in other S.G. ll S.G. is l C-2 result of Il N/A I N/A l l l l ll C-2 l second_ sample _ll l l l l, I Prompt notification to ll Other i Inspect all tubes ll l l l l NRC pursuant to specifi- ll S.G. is I in each S.G. and ll l l

l l l cation 6.9.2. ll C-3 l repair defective ll N/A l N/A ll:

l l l l ll l tubes. Prompt ll l l l l l ll l notification to ll l l l l l ll l NRC pursuant to ll l l l_ l l ll l specification 6.9.2ll l l NOTES: (1) S = 33 % Where N is the number of steam generator in the unit, and n is the number of steam generators n inspected during an inspection.

(2) For tunes inspected pursuant to 4.19.2.a.4: No action is required for C-1 results. For C-2 results in one or both steam generators repair defective tubes. For C-3 results in one or both steam generators, repair l defective tuoes and provide prompt notification of NRC pursuant to specification 6.9.2.

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The program for inservice inspection of steam generator tubes is based on a modification of Regulatory Guice 1.83, Revision 1. Inservice inspection of .s steam generator tubing is essential in order to maintain surveillance of the conoitions of the tubes in the event that there is evidence of mechanical 3 camage or progressive oegradation due to design, manufacturing errors, or b inservice conditions. Inservice inspection of steam generator tubing also .t provides a means of characterizing the nature ano cause of any tube  ;

degradation so that corrective measures can be taken. .m TheUnitisexpectedtobeoperatedinamannersuchthatthesecondary ,

coolant will be maintained within those chemistry limits found to result in negligible corrosion of the steam generator tubes. If the secondary coolant chemistry is not maintained within these chemistry limits, localized corrosion may likely result in stress corrosion cracking. 4 The extent of steam generator tube leakage due to cracking woufd be limited by '"*

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the secondary coolant activity, Specification 3.1.6.3.

The extent of cracking during plant operation would be limited by the limitation of total steam generator tube leakage between the primary coolant ;_

system and the secondary coolant system (primary-to-secondary leakage = F

~g 1 gpm). Leakage in excess of this limit will require plant shutdown and an unscheduled inspection, during which the leaking tubes will be located ano ,_  ;'@

repaired by removal of the tube or degraded portion of the tube from service , T by plugging or a repair method shown to be acceptable by analysis or test, and . @

approved by the NRC. _ (.a g i

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Wastage-type defects are unlikely with proper chemistry treatment of the fih secondary coolant. However, even if a defect would develop in service, it - -B will be found during scheduled inservice steam generator tube examinations. . R~M

, Repair of the degraded tube or portion of tube will be required for . n.~ -

'~G degradation equal to or in excess of 40% of the tube nominal wall thickness ,

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! unlesshigherlimitsareshowntobeacceptablebyanalysisanoarerevieweb y3 and approved by the NRC. Repair will be accomplished by plugging or by_a . . .. Mirig repair method shown to be acceptable by analysis or test, and approved by the .ph ~Y NRC. Steam generator tube inspections of operating plants have demonstrated , - s %

the capability to reliably detect degradation of this type that has penetrated ' - @

l 20% of the original tube wall thickness. 2:&. ji

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Where by USNRC experience in similar Bulletins / Circulars, plants indicate criticalwith areassimilar water at to be inspected, chemistry,4 a

least 50% of the tubes inspected should be from these critical areas.- FirstL- ', . #2 sample inspections sample size may be mooified subject to NRC review and 3%

i approval. _

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GPUN EVALUATION OF SIGNIFICANT HAZARDS CONSIDERATIONS (10CFR 50.91(a) and 10CFR 50.92)

! An evaluation of significant hazards considerations related to this submittal --

can be separated into two parts, an evaluation of the Technical Specification change request, and an evaluation of the approval request for return of the repaired steam generators to service.

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_A. Technical Specification Change

The Technical Specification change is aaministrative in nature. As discussed in the safety evaluation for the change, the revised specification in itself l would not permit any repair techniques except plugging to be used to return a l

steam generator to service after damage has been identified. It would, however, allow the Staff to authorize use of another repair technique after a j separate evaluation, review ano approval.-

, Because no changes are made in the conditions unoer which the steam generators may be operated, without NRC approval, it can be concluded that the change has

- not:

1. Increased the probability or consequences of an accident previously evaluated;

2. created the possibility of a new or different kind of accident from any 4.

accident previously evaluated; i

[ 3. Involved a reduction in a margin of safety.

Thus, no significant hazards considerations are associated with the Technical l Specification change itself.

B. Steam Generator Repair Approval

! On December 10, 1982, we provided the Staff with Topical Report 008, Rev. 1, I our safety evaluation for return of TMI-l to service following repair of the i

steam generators. Revision 2 to this document was supplied to the Staff on i March 31, 1983. A number of the reference documents to the topical report

have also been made available.

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The Topical Report covers the testing and analysis which shaped our conclusions, and the comprehensive precritical and posteritical test program planned to confirm them.

The completed testing and analysis, support the following conclusions:

1. We have sufficient understanding of the failure mechanism to assure safe operation and have taken steps to prevent its recurrence or reinitiation.

2. Our inspection techniques have been adequate to find ano characterize relevant darrage in these steam generators ano the remainder of the reactor coolant system.

3. Our kinetic expansion repair technique is adequate to remove from service all significant defects about 8" above the lower face of the upper tubesheet. The repair creates a new tube-to-tubesheet joint below this point which meets the licensing basis of the original joint, and removes the degraded portions of tubing from the primary system pressure 4

boundary.

4. The number and distribution of tubes pluggeo is such that the performance of the steam generator remain within the licensed basis during normal, transient, and accident conditions.

5. All tubing remaining in service has been examined and found to have no defects of a size which woulo propagate to fa.i lure due to normal

operational vibration or loading, or-to transient or accident loads.

6. Neither the performance of.the kinetic expansion ano plugging repairs, nor the operation of the repaired steam generators will have a detrimental effect on the remainoer of the plant or on the environment, These items have in turn led us to concli , that the repaired steam generator can once again be considered operable a' part of the primary pressure boundary within'the licensea basis.

Because the original licensing basis is not changed, it is concluded that operation using the repaired steam generators ooes not:

i 1. Increase the probability or consequences of an accident previously i evaluated.

2. Create the possibility of a new or different kino of accident from any accident previously evaluated.

3. Involve a reduction in a margin of safety.

Thus, it is concluded that return of the steam generators to service following repair involves no significant hazards considerations.

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