ST-HL-AE-5026, Application for Amend to License NPF-76,revising TS 3.4.5 to Modify SG Tube Plugging Criteria.Nonproprietary & Proprietary Version of W E-Series F* Qualification Rept Encl.Proprietary Version of Rept Withheld

Application for Amend to License NPF-76,revising TS 3.4.5 to Modify SG Tube Plugging Criteria.Nonproprietary & Proprietary Version of W E-Series F* Qualification Rept Encl.Proprietary Version of Rept Withheld

ML20080T416
Person / Time
Site:	South Texas
Issue date:	03/01/1995
From:	Cloninger T HOUSTON LIGHTING & POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML19311B755	List: ML20080T427 ML20080T442 ST-HL-AE-5026, Application for Amend to License NPF-76,revising TS 3.4.5 to Modify SG Tube Plugging Criteria.Nonproprietary & Proprietary Version of W E-Series F* Qualification Rept Encl.Proprietary Version of Rept Withheld
References
ST-HL-AE-5026, NUDOCS 9503130308
Download: ML20080T416 (10)

Text

The Light companySat IIouston Lighting & Power exas mject ect c enenting tadon P. O. Box 289 Wadsworth, Texas m83 March 1, 1995 ST-HL-AE-5026 File No.: G20.02.01 10CFR50.90, 10CFR50.92, 10CFR51 U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555 South Texas Project Units 1 & 2 Docket No. STN 50-498 Unit 1 Technical Specifications 3.4.5 Houston Lighting & Power Company proposes to amend its Operating License NPF-76 for the South Texas Project Electric Generating Station, Unit 1, by incorporating the attached proposed change to Technical Specification 3.4.5. The purpose of this amendment is to modify the Steam Generator tube plugging criteria in Technical Specification 3.4.5, Steam Generators, and the associated Bases. These changes will allow the implementation of alternate steam generator tube plugging criteria for the tube-to-tubesheet joints (known in the industry as F*).

Houston Lighting & Power has reviewed the attached proposed amendment pursuant to 10CFR50.92 and determined that it does not involve a significant hazards consideration. In addition, Houston Lighting & Power has determined that the proposed amendment satisfies the criteria of 10CFR51.22(c)(9) for categorical exclusion from the requirement for an environmental assessment. The South Texas Project Electric Generating Station Nuclear Safety Review Board has reviewed and approved the proposed changes.

The required affidavit, along with a Safety Evaluation and No Significant Hazards Consideration Determination associated with the proposed changes, and the marked up affected pages of the Technical Specifications are included as attachments to the letter.

13004G 4

/C [#4 / M 9503130 sos 950301 8 DR ADOCK 0500 ([p/  :

Project Manager on Behati of the Participants in the South Texas Project .

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Houston Lighting & Power Company .  ;

South Texas Project Electric Generating Station ST-HL-AE-5026 File No.: G09.06 Page 2 As Attachment 4 contains information proprietary to B&W Nuclear Technologies, it is supported  !

by an affidavit signed by B&W Nuclear Technologies, the owner of the information. The affidavit sets forth the basis on which the information may be withheld from public disclosure by the Commission and addresses with specificity the considerations listed in paragraph (b)(4) l of Section 2.790 of the Commission's regulations.  ;

i Accordingly, it is respectfully requested'that the information which is proprietary to B&W '  !

Nuclear Technologies be withheld from public disclosure in accordance with 10 CFR Section j

2.790 of the Commission's regulations.

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Correspondence with respect to the copyright or proprietary aspects of the items listed above or j the supporting B&W Nuclear Technologies Affidavit should reference BAW-10203P and should be addressed to J. Taylor, Manager of Licensing Services, B&W Nuclear Technologies, P. O.  ;

Box 10935, Lynchburg, Virginia 24506-0935. {

In accordance with 10CFR50.91(b), Houston Lighting & Power is providing the State of Texas -  !

with a copy of this proposed amendment. v i

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If you should have any questions concerning this matter, please call Mr. M. A. McBurnett at j (512) 972-7206 or myself at (512) 972-8787. j 1

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. H. Cl inger i Vice P side , ,

Nucl rE meering l TK/lf l

Attachment:

1. Affidavit j

2. Safety Evaluation and No Significant azards Consideration {

Determination  :

3. Mark-ups of Proposed Change to Technical Specifications 3.4.5. ,

4. BAW-10203P, "E E-Series F* Qualification Report", Proprietary l

5. BAW-10203, "W E-Series F* Qualification Report", {

Non-Proprietary l

T5C oheune 002 J

T h n:

Houston Lighting & Power Company ST-HL-AE-5026 -  !

South Texas Project Electric Generating Station File No.: - G02.02.01 -

Page 3 l c:  :

l

' Leonard J. Callan Rufus S. Scott-- .;

Regional Administrator, Region IV' Associate General Counsel - -l U. S. Nuclear Regulatory Commission Houston Lighting & Power Company 611 Ryan Plaza Drive, Suite 400 P. O. Box 61067 l Arlington, TX 76011-8064 Houston, TX 77208 Thomas W. Alexion Institute of Nuclear Power  ;

Project Manager: Operations - Records Center U. S. Nuclear Regulatory. Commission 700 Galleria Parkway j Washington,: DC 20555-0001 13H15 ' Atlanta, GA 30339-5957 1 David P. Loveless Dr. Joseph M. Hendrie  !

Sr. Resident Inspector - 50 Bellport Lane .l c/o U. S. Nuclear Regulatory Comm. Beliport, NY 11713. ,

P. O. Box 910.  !

Bay City, TX 77404-0910 Richard A. Ratliff _

'i Bureau of Radiation Control J. R. Newman, Esquire Texas Department of Health 'I Morgan, Lewis & Bockius 1100 West 49th Street 1800 M Street, N.W. Austin, TX 78756-3189 l Washington, DC 20036-5869  !

U. S. Nuclear Regulatory Comm.'

K; J. Fiedler/M. T. Hardt Attn: Document Control Desk l

City Public Service Washington, D. C. 20555-0001 i P._ O. Box 1771  !

San Antonio, TX 78296 l t

J. C. Lanier/M. B. Lee J. R. Egan, Esquire _ l City of Austin Egan & Associates, P.C. 'l Electric Utility Department 2300 N Street, N.W. l 721 Barton Springs Road Washington, D.C. _20037 Austin, TX 78704 j l G. E. Vaughn/C. A. Johnson

• Central Power and Light Company ,

~ P. O. Box 2121  !

Corpus Christi, TX 78403 ,

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ATTACHMENT 1 AFFIDAVIT -

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. UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION

, In the Matter of ')

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Houston Lighting & Power ) Docket Nos. 50-498 Company, et al., )

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p South Texas Project ' )

Units I and 2 )

AFFIDAVIT I, T. H. Cloninger, being duly sworn, hereb depose and say that I am Vice President, Nuclear Engineering, of Houston Lighting & Power Company; that I am duly authorized to sign -

and file with the Nuclear Regulatory Commission the attached revision'to proposed changes to Technical Specification 3.4.5; that I am familiar with the content thereof; and e matters set forth therein are true and correct to the best of my knowledge and beli fA

. H. Cloni er Vice Pres

• ent, Nuclear ngi ering STATE OF TEXAS )

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Subscribed and sworn to before me, a Notary Public in and for the State of Texas, this /#'

day of Muc A ,1995.

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• a M e A A M lfA w Notary Public in and for tid'

[< s,fg/ my c==== wa dl88d7gfE State of Texas

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i ATTACHMENT 2 SAFETY EVALUATION AND NO SIGNIFICANT HAZARDS CONSIDERATION DETERMINATION FOR STP UNIT 1 F* TUBE PLUGGING CRITERIA Tsceswum l

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e :l ST-HIeAFe5026 Attachment 2 Page 1 of 4 1

i. Description of the Proposed Change h .

L .< Houston Lighting & Power company (HL&P) requests to amend Technical Specifications

'(TS) 3.4.5 Steam Generators, and the associated bases to allow the use of an alternate plugging criteria'(known in the industry as F*) on steam generator tubes that are defective or degraded within certain areas within the tubesheet.- The areas where the alternate criteria will .

E be employed are those portions of the tubes within the tubesheet that have been determined by analysis to be structurally non-relevant to the safe operation of the. steam generator. In the

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tubes that are appropriately rolled into the tubesheet and where cracking is well below the l y point where the tube is rolled to the tubesheet, the 40% through-wall plugging limit will not be imposed. Cracking greater than the 40% limit in this area will not have an adverse impact on the integrity of the pressure boundary of the tube-to-tubesheet joint.

Copies of the Technical Specification pages with the proposed changes indicated are included in Attachment B to this submittal.

< Description of Current Requirement:

The current requi ements identified in Technical Specifications Section 3/4.4.5, Steam Generators, requires tubes to be plugged when degradation exceeds 40% through-wall.

Safety Analysis:

South Texas Project is requesting a change to the technical specifications to allow the use of an alternate plugging criteria for certain areas of the tubing within the tubesheet that exhibit primary water stress corrosion cracking (PWSCC). This will allow more tubes to remain in service and will preserve the function of the tube as a heat transfer surface.

This change applies to STP Unit 1 only. STP Unit 2 tube-to-tubesheet joints are expanded by a hydraulic process and this process is not covered by this requested amendment.

In tubes that are appropriately rolled into the tubesheet, cracking well below the point where the tube is rolled to the tubesheet will not have an adverse impact on the integrity.of the pressure boundary of the tube-to-tubesheet joint. Eddy-current inspections will ensure that the tube-to-tubesheet joint is appropriately configured in the areas that are structurally relevant.

The parameters that are required to determine the characteristics of the tubes where this attemate criteria can be applied and the distances below the secondary face of the tubesheet where the use of the criteria is appropriate, have been determined by analysis and testing.

This analytical work is included in this submittal as attachment 4 and is titled " .W_ E-Series J F* Qualification Report"; BAW-10203P and was prepared by B&W Nuclear Technologies.

TSC-93wHWLOQ2 1

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bb j Attachment 2 Page 2 of 4 Certain tubes have been identified in the Unit I steam generators which are not suitable for application of this criteria. These tubes contain certain rolling anomalies that are characterized as " wavy" and as such are specifically excluded from application of the F*

criteria. These tubes are designated in the Technical Specification change mark-up attached.

Bases of the Proposed Amendment:

The F* altemate plugging criteria has been developed with the objective of preservation of the structural margin specified by the original design. This alternate criteria would allow many tubes to remain in service before operationally constraining the steam generator when  !

compared to removal of the tubes from service by plugging.

Impact of the Proposed Change:

The implementation of the proposed F* attemate criteria does not introduce significant or adverse changes to the plant design basis. Use of the F* criteria will continue to maintain the overall tube bundle structural integrity at a level consistent with that of the originally designed and supplied tubing during all plant conditions.

Based on the above, the proposed amendment request has no significant negative impact on any system or operating mode.  ;

NO SIGNIFICANT HAZARDS CONSIDERATION DETERMINATION Pursuant to 10CFR50.91, this analysis provides a determination that the proposed change to the Technical Specifications described previously, does not involve any significant hazards consideration as defined in 10CFR50.92, as described below: i 1

1. The proposed change does not involve a significant increase in the probability or consequences of an accident previously evaluated.

The proposed changes to the Steam Generator section of Technical Specifications do not affect any accident initiators or precursors and do not alter the design assumptions for the systems or components used to mitigate the consequences of an accident. The requirements approved by the NRC will not be reduced by this request. Since F* utilizes the "as rolled" tube configuration that exists as part of the original steam generator design, all of the design and operating characteristics of the steam generator and connected systems are preserved.

The F* joint has been analyzed and tested for design, operating and faulted condition loadings in accordance with Regulatory Guide 1.121 safety factors. At worst case, a tube leak would occur with the result being a primary to secondary leak. +

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I ST-HleAFe5026 Attachment 2 l Page 3 of 4 l

b itt d by f

Should a tube leak occur, the impact is bounded b I ii f i t increased from the l

created by the use of F* criteria. The potential for a tube rupture s nod as the design f f accident original submittal, thus there is no impact on accidents ev previously evaluated. kind of

2. The proposed change does not create the possibility of a new or differ accident from any accident previously evaluated.

i ificant or adverse The use of the proposed F* alternate plugging criteria in i d unplugged will not introduce s gn changes to the plant design basis. The failuref the oftubesheet, a tube itswhich leak rema nehich is a p accordance with the F* criteria would result inf a tube leak, w f i t sting and previous condition. Since this leak would occur below the seconda a l akages. This 4

experience indicates that normal d used at other and faulted leakage operating conclusion is consistent with previous F* programs approved an plants. l the F*

3 i

However, in the unlikely event the failed bh tube t due toseveredits length ofcompletely at a p region, the remaining F* joint would retain engagement in the tu es eenting a expanded contact within the tubesheet bore, preveF* region, then it is covered by the tube rupture

. tubes. If the tube severs at a point above the ibility of a new or different type of accident

_ event as a part of the UFSAR. Thus, the poss

1. ' rom any accident previously evaluated is not created. f fety.

i Je proposed change does not involve a significant reduction In a m i f the steam generator are at previous responses (above), d hich satisfies theall of protective the necessary boundar e

, draded expanded interface with the tubesheet an w l Specifications.

( and leakage requirements per Reg. Guide 1.121 and i d fthe Technica joint is constrained within the tubesheet bor

'does not reduce the margin of safety.

ges do not involve a significant reduction l d dinthat the margin of safety on the above evaluation, Houston Lighting & Power has conc u e

' ' involve any significant hazards considerations.

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c ST-HIeAFe5026 Attachment 2 Page 3 of 4 Should a tube leak occur, the impact is bounded by the ruptured tube evaluation submitted by ,

'IIL&P for the STP Unit 1 operating license. No new or unreviewed accident conditions are created by the use of F* criteria. The potential for a tube rupture is not increased from the original submittal, thus there is no impact on accidents evaluated as the design basis.

Therefore use of the F* criteria will not increase the probability of occurrence of an accident previously evaluated.

2. The proposed change does not create the possibility of a new or different kind of  ;

accident from any accident previously evaluated.

The use of the proposed F* alternate plugging criteria will not introduce significant or adverse changes to the plant design basis.The failure of a tube which remained unplugged in accordance with the F* criteria would result in a tube leak, which is a previously analyzed  ;

condition. Since this leak would occur below the secondary face of the tubesheet, its leak rate would be limited by the tube-to-tubesheet interface. Qualification testing and previous experience indicates that normal an:1 faulted leakage would be well below the technical specification limits creating no threat associated with tube rupture type leakages. This conclusion is consistent with previous F* programs approved and used at other operating plants.

Ilowever,in the unlikely event the failed tube severed completely at a point below the F*

region, the remaining F* joint would retain engagement in the tubesheet due to its length of expanded contact within the tubesheet bore, preventing any interaction with neighboring tubes. If the tube severs at a point above the F* region, then it is covered by the tube rupture i event as a part of the UFSAR. Thus, the possibility of a new or different type of accident from any accident previously evaluated is not created.

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3. The proposed change does not involve a signifiant reduction In a margin of safety. i Based on previous responses (above), the protective boundaries of the steam generator are preserved. A tube with degradation can be kept in service through F* criteria which provided an un-degraded expanded interface with the tubesheet and which satisfies all of the necessary ,

stmetural and leakage requirements per Reg. Guide 1.121 and the Technical Specifications.

Since the joint is constrained within the tubesheet bore there is no additional risk associated with tube rupture. Since the UFSAR analyzed accident scenarios remain bounding the use of an F* criteria does not reduce the margin of safety.

Thus, these changes do not involve a significant reduction in the margin of safety.

Therefore, based on the above evaluation, Houston Lighting & Power has concluded that these changes do not involve any significant hazards considerations.

TSC-95WSw1W12 l l

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i ST-IIleAB5026 Attachment 2 Page 4 of 4 l Ilouston Lighting & Power has evaluated the proposed amendment against the criteria for identification of licensing and re p. atory actions requiring environmental assessment in i accordance with 10CFR51.22(c)(9). It has been determined that the proposed change meets  !

the criteria for a categorical exclusion as provided for under 10CFR51.22(c)(9). This ,

I determination is based on the fact that the proposed change does not involve a significant hazards consideration as discussed in Attachment C to this letter, will not involve significant changes in the types or amounts of any radioactive effluents, does not affect any of the permitted release paths, and does not involve a significant increase in individual or cumulative '

occupational exposure. Therefore, this change meets the categorical exclusion requirements permitted by 10CFR51.22(c)(9).

Schedule Requirements:

llouston Lighting & Power requests this amendment be given an expeditious review and approval prior to April 10,1995 the end of the upcoming STP Unit I refueling autage.

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