ST-HL-AE-3906, Application for Amends to Licenses NPF-76 & NPF-80,revising Updated Final Safety Analysis Rept for Extended Burnup Fuel. No Significant Impacts Associated W/Proposed Change & License Amend Will Have No Significant Effect of Environ

Application for Amends to Licenses NPF-76 & NPF-80,revising Updated Final Safety Analysis Rept for Extended Burnup Fuel. No Significant Impacts Associated W/Proposed Change & License Amend Will Have No Significant Effect of Environ

ML20079L195
Person / Time
Site:	South Texas
Issue date:	10/30/1991
From:	Rosen S HOUSTON LIGHTING & POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20079L196	List: ML20079L225 ST-HL-AE-3906, Application for Amends to Licenses NPF-76 & NPF-80,revising Updated Final Safety Analysis Rept for Extended Burnup Fuel. No Significant Impacts Associated W/Proposed Change & License Amend Will Have No Significant Effect of Environ
References
ST-HL-AE-3906, NUDOCS 9111060158
Download: ML20079L195 (15)

Text

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"**'""" "" ""' # "^*""'l" Cetober 30, 1991 ST llL-AE 3906 File No, C25 10CFR50 U. S. Nuclear Regulatory Commission Attention: Document Control Desk Vashington, DC 20555 South Texas Project Electric Generating Station Unita 1 & 2 Docket Nos. STN 50-498, STN 50-499 Proposed Revision to Updated Final Safety Analysis Report for Extended Burnup Fuel South Inmfrgip.St Electric ,Q.gturnline Statign_MIf19M Pursuant to 10CFR50.90, Houston Lighting & Power Company (HIAP) hereby proposes to amend its Operating Licenses NPF 76 and NPF-80 with the attached changes to the Updated Final Safety Analysis Report for Units 1 6 2.

H14P has reviewed the proposed change in accordance with the requirements of 10CFR50.59 and 10CFR50.92. The change involves an Unteviewed Safety Quertion (USQ) since revised equipment doses exceed the current NRC acceptance limit in the STPEGS Safety Evaluation Report (SER), NUREG-0781.

Based upon SER Supplement 4 which presents the riRC acceptence criteria, the proposed changes to UFSAR Table 3.11 1 for equipment doses inside contaitunent (1.5E48 rads) exceed the previously re/lewed and accepteo NRC accept.ance criteria of 3.4E+8 rada. llowever the increased doses remain substantially below established limits and no modification to plant design in involved.

The proposed change involves increasing the STPEGS cycle length and therefore the burnups assumed in developing the radiological source terms.

The purpose of the proposed change is to reflect the use of longer fuel cycles at STPECS by increasing the nominal cycle length to 20,000 MVD/MTU, the core average burnup to 40,000 it?D/MTU, and the region average discharge burnup to 45,000 MVD/MTU.

The amendaent revises UFTAR Sections 3.11.5.2, 4.3.1.1, 4,3.2.1, 4.3.2.4.14, 11.1, 12.2.1.2, and Tables 1,6-1 and 3.11 1, as shown on the marked up pages in Attachment 2. Sections 11.1.6, 12.2.3, and 15.A.4, as shown in Attachment 2, are added to the UFSAR.

The change in core average discharge burnup limit is needed for operation of the current Unit 1, Cycle 4 to its design burnup of 456 effective full power (EFPD). IllAP requests the NRC to review this USQ expeditiously so that STPEGS will be able to implement the proposed change by June 10, 1992, prior to the end of Unit 1 Cycle 4. 'ly m1 _ i_

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..llouston Ll;hting & Power Company 1 South Texas Projut Elutric Generating Station ST IIL AE 3906 File No G25 j Page 2 i t

Based on the inforsaation contained in this submittal and the NRC Final Environmental Asseesment for South Texas Units 16 2, lilAP has concluded that pursuant to 10CFR51.22 there are no significant radiological or non-  ;

radiolo6 1cal impacts associated with the proposed change and that the proposed license amendment will not have a significant effect on the quality of the human environment. ,

The South Texas Project Nuclear Safety Review Board has reviewed and ,

approved the attached proposed revir,lon and concurs with the 10CFR50.59 determination.

In accordance with 10CFR50.90. HLAP therefore requests that if censes

- NPF 76 and NPF 80 for STP Units 1 and 2 be amended to allow incorporation of ,

the proposed change to equipment doses.

In accordance with 10CFR50.91(b), lilAP is providing the State of Texas with a copy of this proposed amendaent.

If you should have any questions on this matter, please contact  ;

Mr. A. V.-alarrison at (512) 972 7298 or me at ($12) 972 7138.

S. L. Rosen ,

Vice President.

Nuclear Engineering SDP/an:p

. Attachment (s); 1) Description of Change

2) Determination of No Significant flazards ,

3) Proposed UFSAR Revisions d

)

i USQ\91-267.001 m - v- --.- ~ . ~ .m - . . . - . . , . _ . _ . _ _ _ _ _ . _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ . _ _ _ _ _ _ _ _ _ . _ _ _ _ _ _ _ _ _ _ _ . _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ . _ _ _ _ . _ _ _ _ _ . _ _ _ _

4 ST ilL AE-3906 File No. G25 Page 3 UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION In the Matter )

)

Houston Lighting 6 Power ) Docket Nos. 50-498 Company, et al., ) 50 499

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South Texas Project )

Units 1 and 2 )

Aff11%.Y11 S. L. Itosen, J r. heing duly sworn, hereby deposes and says that he is Vice Presidtnt, Nuclear Engineertry;, of Houston Lighting & Power Company; that he is duly authorized to sign and file with the Nuclear Regulatory Commission the proposed revistor to the Updated Final Safety Analysis Report for extended burnup fuel; is familiat with the content thereof; and that the matters set forth theteln are true an.1 correct to the best of his knowledge ai.d belief,

..a &

L. Rosen s..e Presider.t. Nuclear Engineering STATE OF TEXAS )

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)

Subscribed and sworn to before me, a Notary Public in and for The State of Texas this cAfi/ day of ddM//L , 1991, M 2

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sAvANhA $ FRA to ,rutw.!an sinn N tary Public in and f or the-

[8[,hJ. u, c. mew bro r tr,$4 Mate of Texas

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s ST llL- AE* 2 90 6 llouston 1.is;htir.g & Power Compai y File No.: t; 2 5 South Texas Projut 1;tettric Generating Station Page 4 cc:

Regional Administrator, Region IV Rufuu S. Scott Nuclear Regulatory Comminulon Associate General Counsel 611 Ryan Plaza Drive, Suite 400 llouston 1.ighting f. Power Co:tpany Arlington, TX 76011 P. O. Box 61867 Ilouriton, TX 77208 George D';k, Project Manager U.S. W..olear Re6ulatory Commission INPO Vashington, DC 205% Records Center 1100 Circle 75 Parkway J. 1. T4pla Atlanta. CA 30339-3966 Senior Resident Inspector c/o U. S. Nuclear Regulatory Dr. Jorieph M. llendrin Commission 50 Bellport Lane P. O. Box 910 Bellport, NY 1171')

Bay City, TX 77414 D. K Lacker J. R. Newman, Esquire Bureau of Radiation Control Ne wman & lloitzinger, P.C. Texas Department of llealth 1615 L Street, N.W. 1100 Vest 49th Street Washington, DC 20036 Austin, TX 78756 3189 D. E. Ward /T. M. Puckett Central Power and Light Company P. O. Box 2121 Corpus Christi, TX 78403 J . C . 12nic r/M . B . Le e City of Austin Electric Utility Departnient P.O. Box 1088 Austin, TX 78767 K. J. Fledler/M. T. liardt City Public Servico Board P. O. Box 1771 San Antor TX 76296 Revised 10/11/91 L4/NRC/

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ATTACllMLNT 1 DESCRIPTION OF CllANGE l

Ut.Q101 28' .001

4 Attachment 1 ST-ill. AE. 3906 Page 1 of 4 D MCRIPTION OF CHANGE The radiological source terms which appear in the STPEGS Updated Fina' Safety Analysis Report (UFSAR) are used for determining the radiological aspects of the plant design. The current source term values reflect a nominal 12 month fuel cycle. The source terms are based on a three region, equilibrium core with a cycle length of 11,900 MVD/HTU, a core average burnup of 23,700 MVD/MTU, and a discharge burnup of 35,600 MVD/MTV. The current core avetage burnup limit is approximately 23,740 MVD/HTU (Reference 1).

The purpose of the proposed change is to reflect the use of longer fus) cycles at STPEGS by increasing the nominal cycle length to 20,000 MVD/MTU, tF.

core average burnup to 40,000 MVD/MTV, and the region average discharge burtep to 45,000 MVD/MTU.

The proposed change involves an Unreviewed Safety Question since the revised equipment -es will exceed the current NRC acceptance limit in the SER (Reference 2). The increases in equipn. cut qualification radiation doses due to the proposed change are enveloped by the qualification data with sufficient margin as required by 10CFR50.49 and other qualification standards (References 3 and 4). Therefore, the proposed changes to equipment doses do not pose a significant increase in hazard.

The effects of the pre osed changes on other radiological analyses do not significantly impact the results of these analyses as presented in the UFSAR and do not poso a significant increase in hazards.

Erpposed C.hange The proposed change is to modify UFSAR Sections 3.11.5.2, 4.3.1.1, 4.3.2.1, 4.3.2.4.14, 11.1, 12.2.1.2, and Tables 1.6-1 and 3.11 1, with the marked-up sections as shown in Attachment 2. Sections 11.1.6, 12.2.3, and 15.A.4, as shown in Attachment 2, are added t< .he UFSAR.

Ea[ gly ly.a1uation The purpose of this section is to discuss the impact of the proposed thange on the design and licensing basis of the plant. This section will aidress lupacts on the following areas:

Equipment Qualification; Accident Analyses Offsite Doses; Normal Plant Radionuclide Inventeries, Releases, and Doses; Plant Shielding and Worker Occupational Radiation Doses.

14Q\ 91-267. 001

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l Attachment 1 ST ill- AE 3906 Page 2 of 4 The NRC has approved the use of extended burnup tvel as documented ir NUREG/CR 5009, " Assessment of the Use of Extende(' Burnup Fuel in Light Water Power Reactors" (Reference 5). This NUREG was referenced in >ER Supplement 6 (Reference 6) to approve the extension of Unit 2 Cycle 1 to 400 FFPD.

[mtirment Ogallfl.c.at.[pm The analyses which supporta the equipment qualification doses presented in UFSAR Table 3 11 1 were updated to incorporate the proposed change in _

source terra. A summary of the changes in equipment qualification doses is given in Table 1.

The proposed source ' ems were calculated on a basis of a cycle length of approximately 20,000 MWD /MTU, a eire average burnup of approximately 40,000 MVD/MTU, and a region discharge but:.up of approximately 60,000 MVD/MTU. These assumptions bound the UFSAR proposed change to e 20,000 MWD /MTU cycla length, ,

a 40,000 MVD/MTU core averago burnup, end a 45,0' 0v MWD /MTU region discharge burnup. The proposed source terma also use an increased fuel enrichment of 4.S veight percent U-235. The effects of the change in design enrichment have previoucly been analyzed by illAP and approved by the NRC in Reference 1.

The NRC acceptance criteria for equipment qualification is defined by SER Supplement 4 (Rsference 2). Section 3.11 of this Supplement states:

"The maximum value specified by the applicant for use in equipment qualification inside containment and in areas outside containment exposed to post-IDCA recirculating fluid environment is 1.4E+8 rads (gamma plus beta).

This value is acceptable for use in the qualification of equipment." .

Based upon this acceptance criteria, the proposed changes to Table 3.11 1 for equipment doses inside containment (1.5E48 rads) exceeds the previously reviewed and accepted NRC acceptance criteria of 1.4E48 rads.

IlL&P has evaluated the radi it ion doses due to the proposed change and concluded that the increased dos.n are still enveloped by the qualification data with sufficient margin as required by 10Cra50.49 and other qualification standards (References 3 and 4). Therefore, the changes to equipment doses do not pose a significant increase in hazard.

Proposed changes to Sect. ion 3.11.5.2 and Table 3.11-1 of the UFSAR reflect ti,e use of tl.e revised source terms and the revised equipment doses.

03Q)D1-287.001

4 Attachment 1 ST ilt- AE-3906 Page 3 of 4 6grisient Analyset Offsite Qo m Accident ar.9 yser offsite doses are discussed in UFSAR Chapter 15, the Environmentel Report, and the Final Environmet t cl Statement . NUREC/CR-5009,

" Assessment of the Usa of Extended Burnup Fuel in Light Vater Power Reactors" (Reference 5) discusses the impact of high burnup fuel on accidents.

NUREG/CR 5009 reviewed accidents that involved the damage or melting of the fuel in the reactor core. For accidents in which the core remains intact, involving only volatile fission products, it was determined that no increases in impacts would occur. For nore severe accider.is, ones involving fuel melt, only a few fission preducts and the actinides would increase in inventory with increased burnup. NUREC/CR 5009 concluded that the factors of increases in the radioactive sources were less than the uncertainty involved in deterr ia'ng the overall risk to the public.

The fuel handling accident is impacted because the calevlated iodine-131 gap-release fraction is 20% greater than the Regulatory Guide 1.25 assumed value of 0.10. Ther* fore, the calculated thyroid doses with extendeu burnup fuel resulting from a rael handling accident could be 20% higher than estimated using the Regulatory Guide.

The NRC has reviewed the ef fect of the usa of extended burnup fuel (up ,

to 60,000 MVD/MTU peak rod) at STP Unit 2 Cycle 1 and found it to be acceptable (Reference 6) for a Cycle 1 length of 400 EFPD. A t04 increase in the thyroid dose due to a fuel handling accident would increase the STPECS dose value from 24.6 rem to 29.5. This is still belca the tRC acceptance 14.mit of "less than or equal to 25% of the ICCFF10 caragraoh 11 axposure guideline values, i.e., less than or equal tt 75 r a to the thyroid . _

(Reference 6).

Normal Pla.1r &acienuclide Inventories. Releas m and Doses Normal plant radionuclide inventories, relesses, and doses are discussed in the UFSAR Chapter 11, the Environmental Report, wel the Fir.a1 Environmental Statement. NUREC/CR-5009 discussed the change in release fractions for the major isotopes affecting doses from normal operation. Although the system inventoties would increase, the normal plant cleanup systems could handle this increase. NUREG/CR-5009 concludes that "the environmental impact for normal operation will not change when extending fuel burnup."

USQ\91 '!B7.001

2 Attachment 1 -)

ST-llL AE-3906 i Page 4 of 4

Plant Shielding and Werker Occunational Radiation Doseg Plant shielding and worker occupational rrdiat',on doses are discussed in UFSAR Chapter 12, the Environmental Report, the Fin'al Environmental: Statement,- 'I

- and the Offsite Dose Calculation Manual. NUREG/CR 5009 discussed the change

.in release fractions for the major isotopes affecttng doses from normal operation.- Although the-system inventories would tr. crease,_the normal plant cleanup systems could handle this increase. Radiation Zones, both inside and

.- outside the-plant,.would not be impacted. The plant shielding design would not be significantly impacted by, extended burnup fuel.

Sinct no significant change in system inventories would occur, i-occupational dosos;to workers would not change. Indeed NUREG/CR-5009 states that worker doses due to refueling operations would decrease, since there -

would be fewer refueling campaigns.

UNPa P287.001

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l ATTACHMEN7 2 DETF"MINATION OF NO SIGNIFICANT IIAZARDS i

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t USQi91 287,001

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-Attachment 2 ST-HL AE.3906  :)

Page 1 of 5 i DETERMINATION OF NO SIGNIFICANT HAZARDS Pursuant to 10CFR50.91, this analysis provides a determination that the 1 proposed change to the UFSAR_does not involve significant hazards

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considerations as defined in 10CFR50.92. 1 (1) The proposed change does not involve a significant increase in the probability or consequences of an accident previously evaluated.

Eculoment Oualification Based upon SER Supplement 4 which presents the NRC acceptance criteria, the proposed changes to UFSAR Table 3.11-1 for equipment doses inside containment (1.5E+8 rads) exceeds the previously 14 reviewed and accepted NRC acceptance criteria of 14E+8 rads.

- HL&P has evaluated the . increased doses -against the present

- equipment qualification documentation. This evaluation concludes that the increases in radiation doses due to the proposed change are still enveloped by the qualification data with sufficient margin as required by 10CFR50.49 and other qualification standards (References.3 and 4). Therefore,-the changes to equipment doses do not involve a significant increase in the probability or consequences of an accident previously evaluated.

Other Radiological Analyses 1 Extended burnup fuel has been approved by the NRC in NUREG/CR-5009,

" Assessment of the Use of Extended Bu.:nup Fuel in Light Water

' Power Reactors". 'This document was referenced in SER Supplement 6 (Reference-6) to approve the extension of Cycle 1-of Unit 2 to-400 EFPD.

NUREG/CR-5009 states that for Chapter 15 accidents, except for the  :

fuel handling accident, "the factors of increases in the radioactive sources are less-than the uncertainty involved in determining the overall risk to-the public."

A 20% increase in the thyroid dose due to a-fuel handling accident would increase the STPEGS dose value from 24.6 rem to-29.5. This E is still below the NRC acceptance limit of "less than or equal to 25% of the 10CFR100, Paragraph 11 exposure guideline values, i.e., ,

less than or equal to 75 rem to the thyroid" (Reference 6).

USQ\9 M 47.001

e Attachment 2 ST.HL AE-3906 Page ? of 5 Therefore, based on the NPC's findings in NUREG/CR 5009 and in the

.l STPEGS SER Supplement 6 (Reference 6), the effects of the proposed changen on the radiological consequences of postulated accidents do not significantly impact the results of these analyses as presented  ;

in the UFSAR and do; not involve a significant increase in the l probability or consequences 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, Eculoment Oualification Since the equipment in the impacted areas has been qualified for dose levels greater than the revised dose projections, the

. probability for equipment failure has not been increased.

Therefore, the proposed change does not create the possibility of a q new or different kind of accident from any accident previously evaluated.

Other Radiological Analyses The proposed change involves increasing the cycle length and,

. therefore, the burnups assumed in developing the radiological

source terms. NUREG/CR-5009 states that the effect on the source terms is small. This proposed change does not create the I' '

possibility of a new' or different kind of accident from any

. accident previously evaluated.

(3) The proposed change does.not involve a significant reduction in a margin of safety.

ll Eautoment Oualification HL&P has evaluated the increased doses- against the present

-equipment qualification documentation. This evaluation concludes

.that the increases in radiation doses due to the proposed change are still enveloped by the qualification data with sufficient margin as required by 10CFRSO.49 and other qualification standards

-(References 3 and 4). Therefore, the changes to equipment dowes do

-not involve a significant reduction in a margin of safety.

Other Radiological Analyses

. NUREG/CR-5009 states that for Chapter 15 accidents, except for the-fuel handling accident, "the factors of increases in the radioactive sources are less than the uncertainty involvad in det

rmining the overall risk to the public."

5 UNE91-287.001

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Attachment 2 ST HL AE 3906 Page 3 of 5 For the fuel handling accident, a 20% increase in the thyroid dose due to a fuel handling accident would increase the STPEGS dose value from 24.6 rem to 29.5. This is still below the NRC acceptance limit of less than or equal to 25% of the 10CFR100, Paragraph 11-exposure Buideline values (Reference 6).

The effects of the proposed changes on plant system radioisotopic inventories, plant shielding, normal radioisotope releases, normal offsite doses, worker occupational doses, and on the radiological consequences of postulated accidents do not significantly impact the results of these analyses as presented in the UFSAR and do not involve a significant reduction in a margin of safety.

Conclusion i l

The proposed changes to the UFSAR, as described above, are l acceptable because the proposed changes to source terms to reflect the use of extended burnup fuel do not pose a significant increase in hazard or involve a significant reduction in a margin of safety, llL&P requests approval of the proposed changes.

USQ\91-Z87.0'1

.t-Atcachment 2 ST llL-AE-3906 Page 4 of 5

. TABLE 1 Environmental Qualification Accident. Doses Effected By Proposed Change Present Proposed Acceptance Acceptance Inside Containment Present Dose Limit Limit ~

Reactor Cavity 1,4EtB Rads 1.4E+8 Rads 1.5E+P Rads (Rms._001, 002)

. 1 Other Areas Inside 1. 4 E+ 8 1.4E+8 1.5E+8 Secondary-Shield j (Below El. 19:ft, l Rm. 004)

-Other Areas Outside 1.4E48 1,4E+8 1. 5 E4 8 Secondary Shield a

USQ\91 287.001-

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-Attachment 2 ST-llL AE-3906 Page 5 of $~

Referenegg

1. -ST AE HL 92490, Issuance of Amendment Nos. 16 and 6 to Facility Operating License Nos. NPF-76 and NPF South Texas Project, Units 1 and 2. (Change permitting-the use of fuel with maximum enrichments Lof 4.5 veight percent Uranium 235.)

2. Safety Evaluation Report, NUREG-0781, Supplement 4

3. IEEE 323 1974, " Qualifying Class IE Equipment for Nuclear Power Generating Stations."

4. NUREG-0588, Rev 1, " Interim Staff Position on Environmental Qualification of Safety-Related Electrical Equipment."

5. " Assessment of the Use of Extended Burnup Fuel in Light Water Power Reactors", NUREG/CR 5009, February 1988, 6, Safety Evaluation Report, NUREG-0781, Supplement 6, Appendix Z,

" Annotated FSAR Revisions Regarding the Revised Cycle 1 Core Design / Energy Requirements."

1 4

USQ\ 91-287. 001 5

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ATTACILMENT 3 MARK-UPS_OF PROPOSED UFSAR REVISIONS 1

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