ST-HL-AE-3387, Application for Amends to Licenses NPF-76 & NPF-80,revising Tech Spec 5.3.1 to Allow Max Enrichment of 4.5 Weight % U-235 to Increase Fuel Discharge Burnups in Future. Criticality Analysis of South Texas Units 1..., Also Encl
| ML20012B091 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 03/01/1990 |
| From: | Rosen S HOUSTON LIGHTING & POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20012B092 | List: |
| References | |
| ST-HL-AE-3387, NUDOCS 9003130489 | |
| Download: ML20012B091 (8) | |
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(Houston Li ng & Power March 1 1990 ST HL AE-3387 File No.: C9.06, G20.01 10CFR50.90 10CFR50.92 10CFR51 U. S. Nuclear. Regulatory Commission Attention: Document Control Desk Washington, DC" 20555 South Texas Project Electric Generating Station Units 1 & 2 Docket Nos. STN 50-498, STN 50-499 Proposed Amendment to the Unit 1 and Unit 2 Technical Soecification 5.3.1
. Pursuant to 10CFR50.90, Houston Lighting & Power Company (HL&P) hereby.
. proposes to amend its' Operating Licenses NPF-76 and NPF-80 by incorporating-the attached proposed change to the Technical Specifications for'the South-Texas Project Electric Generating Station (STPEGS) Units 1 and 2.
'The proposed change consists of allowing a maximum enr!chment of Uranium 235 (U-235) of 4.5 weight percent to allow STPEGS to increase fuel discharge burnups.in the future. A cycle specific Reload Safety Evaluation, including an environmental evaluation considering offsite radiological consequences will be-performed prior to exceeding the burnup assumptions in the._STPEGS FSAR.
HL&P has reviewed the attached proposed amendment pursuant to 10CFR50.92 and determined that it does not involve a significant hazards consideration.
The basis for this determination is provided in the attachments.
In addition, based.on the information contained in this submittal and in the NRC Final
-Environmental Statement related to the operation of STPEGS Units 1 and 2, HL&P has concluded that, pursuant to 10CFR51, there are no-significant radiological
.or non-radiological impacts associated with the proposed action and the proposed license amendment will not have a significant effect on the quality of the environment.
The STPEGS Nuclear Safety Review Board has reviewed and approved the proposed changes.
In accordance with 10CFR50.91(b), H14P is providing the State of Texas with a copy of this proposed amendment.
A1/009.N12 A Subsidiary of Houston Industries incorporated hh 9003130489 900301 PDR ADOCK 05000498 p-PDC I. /
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ST-HL AE-3387 File No.:
C9.06,-C20.01-Page 2 If you should have any questions concerning this matter, please contact Mr. M. A. McBurnett at (512) 972 8530 or myself at (512) 972-7138.
S. L. Rosen Vice President Nuclear Engineering and Construction GCS/n1 Attachments:
1.
Significant Hazards Evaluation for a Maximum U-235 Enrichment of 4.5 Weight Percent 2.
Proposed Technical Specification Change 5.3.1 3.
Criticality Analysis of the South Texas Units 1 and 2 Fresh Fuel Racks 4.-
Mark-up of the Updated Final Safety Analysis Report I
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' ST HL-AE 3'87 Houston Lighting & Power Company-File No.: 0>.06, G20.01 South Texas Project Elcetric Generating Station Page 3 cc:
Regional Administrator, Region IV Rufus S. Scott Nuclear Regulatory Commission Associate General Counsel 611 Ryan Plaza. Drive, Suite 1000 Houston Lighting & Power Company Arlington, TX: 76011 P. O. Box 61867 Houston, TX 77208 George Dick, Project Manager U.S. Nuclear Regulatory Commission-INPO Washington, DC 20555 Records Center 1100 Circle 75 Parkway J. I. Tapia-Atlanta, CA 30339 3064 Senior Resident Inspector c/o U. S. Nuclear Regulatory Dr. Joseph M. Hendrie Commission 50 Be11 port Lane P.-0.
Box 910 Be11 port, NY 11713
-Bay City, TX 77414 D. K. Lacker J. = R. Newman, Esquire Bureau of Radiation Control Newman & Holtzinger, P.C.
Texas Department of Health 1615 L Street, N.W.
1100 West 49th Street Washington, DC 20036 Austin, TX 78704 D. E. Ward /R P. Verret Central Power & Light Company P
- 0. Box 2121 Corpus Christi, TX 78403
- J. C. ianier -
Director of Generation City of Austin Electric Utility 721 Barton Springs Road
-Austin, TX 78704 R. J. Costello/M. T. Hardt City Public~ Service Board P. O. Box 1771 San Antonio, TX 78296 Revised 12/15/89 LA/NRC/
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UNITED STATES OF AMERICA I
NUCLEAR RECULATORY COMMISSION In the Matter
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Docket Nos. 50-498 Company, et al.,
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AFFIDAVIT S. L. Rosen being duly sworn, hereby deposes and says that he is Vice President, Nuclear Engineering and Construction, of Houston Lighting & Power Company; that he is duly authorized to sign and file with-the Nuclear Regulatory Commission the attached proposed change to the South Texas Project Electric Cenerating Station Technical Specification 5.3.1 is familiar with the content thereof; and that the matters set forth therein are true and correct to the best of his knowledge and belief, d
1 S. L M osen Vice President Nuclear Engineering and Construction Subscribed and sworn to before me, a Notary Public in and for The State
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1 ATTACHMENT 1 SIGNIFICANT HAZARDS EVALUATION FOR A MAXIMUM U 235 ENRICHMENT OF 4.5 WEIGHT PERCENT
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ATTACHMENT 1 SIGNIFICANT HAZARDS EVALUATION FOR A-MAXIMUM U-235 ENRICHMENT OF 4.5' WEIGHT PERCENT Backcround In order to reduce fuel costs and conserve spent fuel storage STPEGS is e
. planning to increase discharge burnups.
This will require storage of fuel with r
enrichments higher than those currently allowed by Technical Specifications.
The current Technical Specification 5.3.1 contains a maximum enrichment limit of
'3.5 weight percent for U-235.
STPEGS currently plans to receive shipments of 3.6 weight percent fuel in June of 1990.
Therefore, a change to Technical Specification 5.3.1 will be required.
STPEGS may store new fuel in either the Fresh Fuel Racks or Region I of the High Density Spent Fuel Racks.
STPECS performed an analysis for storing new fuel in Region I of the High Density Spent Fuel Racks with enrichments up to 4.5 weight percent U 235.
The High Density Spent Fuel Racks have also been analyzed for storage of spent fuel with. initial enrichments up to 4.5 weight percent U 235. These analyses were submitted to the NRC by letter.(ST-HL-AE-2417) dated March 8, 1988. The NRC approved this proposal in the Amendment 2 to Operating License, NPF-76 dated November 1, 1988. The same design was approved for Unit 2 at the time its operating license was issued.
The Safety Evaluation below confirms acceptability of the STPECS Fresh Fuel Racks for storage of new fuel with enrichments of up to 4.5. weight percent
'U-235.
Proposed Chance Change Technical Specification 5.3.1'to allow a maximum U-235 enrichment of 4.5 weight percent.
Safety Evaluation Westinghouse has completed a " Criticality Analysis of the South Texas Units 1 and 2 Fresh Fuel Racks".
This analysis demonstrates that Westinghouse 17x17STD, XL, OFA, and Vantage 5 fuel with an enrichment of 4.5 weight percent can be stored in'every location of the fresh fuel rack (Attachment 3).
The NRC Standard Review Plan (SRP) 9.1.1, "New Fuel Storage" requires that effective multiplication factor (K.rt) be maintained less than 0.95 for full density moderation and less than 0.98 for low density moderation.
The design bases for preventing criticality outside the reactor is that there is a 95 percent probability at a 95 percent confidence level that the K.tr of the fuel assembly array will be less than 0.95.
This is recommended in ANSI 57.3-1983 and in the NRC letter to all Power Reactor Licensees dated April 14, 1978.
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- Determination of Sicnificant Hazards
- Pursuant to 10CFR50.91 this analysis provides a determination that the proposed change to Technical Specifications does not involve any significant hazards consideration as defined in 10CFR50.92.
(1) The proposed change does not involve a significant increase in the probability or consequences of an accident previously evaluated. A criticality analysis was performed for the Fresh Fuel racks at STPEGS. This analysis demonstrates that the-criteria of the Standard Review Plan, Section 9.1.1 "New Fuel Storage" is met.
The fresh fuel racks when fully loaded in a flooded condition maintain K.tr at 0.9252 which is below the required maximum of 0.95.
The fresh fuel racks under low density conditions maintain a K,gg of 0,9361.which is below the maximum of 0.98.
Additionally, the evaluation of a fuel assembly drop demonstrated that the K,gg remains below 0.95.
The High Density Spent Fuel Racks have been approved for storage of spent fuel up to 4.5 weight percent U-235 and Region I of these racks has been approved for storage of new fuel with enrichments up to 4.5 weight percent.
Therefore, since the above conditions are the accidents previously evaluated and K,gg is maintained within the appropriate acceptance criteria the probability or consequences of an accident previously evaluated are not signif1cantly increased.
(2) The proposed change does not create the possibility of a new or different kind of accident from any previously evaluated. There are no new scenarios for new accidents or equipment malfunctions created.by the proposed change. Additionally, there are no changes to systems or fuel handling procedures as a result of the proposed change.
(3) The proposed change does not involve a significant reduction in a margin of safety. The Standard Review Plan, Section 9.1.1 provides the margin to criticality. The worst case K,gt evaluated is within the acceptance criteria of the Standard Review Plan. Therefore, the proposed-change does not significantly reduce the margin of safety.
Conclusion Based on the above, HL&P concludes that the proposed change satisfies the significant hazards consideration standards of 10CFR50.92(c) and a no
- significant hazards consideration finding is justified.
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Page 2 Safety Evaluation. Cont'd.
In the criticality analysis performed for STPECS for full water 8
density _a moderator density of 1.0 gm/cm was selected with the water at 68'F.
This results in a K.tr of 0.9252 at a 95/95 probability confidence level.
Since K.tr is less than 0.95, including uncertainties, the acceptance criteria is met.
The maximum rack K rr under low density moderation conditions occurs e
a at 0.043 gm/cm water density. The K rr under these conditions including e
uncertainties is 0.9361.
This K.rt at a 95/95 probability confidence level is below 0.95 and the acceptance criteria for criticality is met.
The analytical methods used are AMPX for the neutron cross section generation and KENO IV, a Monte Carlo computer code for the reactivity determination. These codes have been found acceptable by the NRC staff because_the results obtained for the criticality experiments are satisfactory and these codes are widely used by the industry for fuel storage rack analyses. Additional details of the criticality analytic methods are contained in Attachment 3.
In' evaluating the postulated accidents under normal conditions the fresh fuel racks are normally dry. The introduction of water is a worst caso scenario. The full density and low density optimum moderation cases are bounding accident situations which result in the bounding K.tr.
In the evaluation of a fuel-assembly drop, ANSI N16.1-1975 does not require two unlikely independent concurrent events to protect against a criticality accident.
Therefore, the absence of a moderator in the fresh fuel racks is the initial condition of an accident involving a fuel assembly dropping.
The maximum reactivity increase for postulated accidents will be less than 10%
delta k/k. The normal, dry fresh fuel rack reactivity is less than 0.70.
Therefore, for postulated accidents the maximum rack K.tr will be less than 0.95.
The fission product inventories identified in Appendix 15A of the Updated Final Safety Analysis Report are bounding for a core-average burnup of 23,740 Megawatt Days / Metric ton (MWD /MT). A cycle specific Reload Safety Evaluation is performed for each cycle. A cycle specific Reload Safety Evaluation, including an environmental evaluation considering offsite radiological consequences, will be performed prior to exceeding a core-average burnup of 23,740 KWD/MT. These evaluations will be performed in accordance with 10CFR50.59.
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