ML20064E359
| ML20064E359 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 03/04/1994 |
| From: | Powers K TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9403140263 | |
| Download: ML20064E359 (8) | |
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4 HA Tennem va, Aumomy em o%e tu nema, tam tre,eme ana March 4, 1994 U.S. Nucicar Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555 Gentlemen:
In the Matter of
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Docket Nos. 50-327 Tennessee Valley Authority
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50-328 SEQUOYAll NUCLEAR PLANT (SQN) - UNITS 1 AND 2
" EVALUATION OF INCREASED FUEL BURNUP ON EQUIPMENT QUALIFICATION"
Reference:
NRC letter to TVA dated November 30, 1993 Based upon NRC's review of SQN's' justification for continued operation (JCO) listed in the above reference, SQN was requested to perform a reassessment of equipment qualification for 1,000 effective full power days.(EFPD) burnup. The purpose of this letter is to provide the revised JC0 as requested in the above reference.
SQN has reanalyzed the loss-of-coolant-accident analysis to evaluate radiation doses associated with 4.5 percent Uranium (U)235 enrichment nuclear fuel with a reactor core burnup at -1,000 EFPD.
The reanalysis is based upon the source terms provided in Technical Information Document 14844 and Regulatory Guide 1.89.
Following this analysis, a review of the 10 CFR 50.49 binders was performed. The qualification doses documented in each of the equipment qualification binders were compared to that calculated for 1,000 EFPD.
Based upon this comparison, SQN's 10 CFR 50.49 equipment and cabling remain qualifiable to the increased radiation dose.
The enclosure contains the revised JC0 that bounds reactor core designs with U235 average enrichments less than 4.5 percent.
This includes the Unit 2 Cycle 6, Unit 1 Cycic 7, and Unit 2 Cycle 7 fuel cycles.
Further-analysis is planned to bound higher U235 enrichments (i.e., 5 percent) for a core burnup cycle of 1,000 EFPD.
9403140263)940304 3
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PDR-ADOCK 05000327 T
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March 4, 1994 i
Please direct questions concerning this issue to W. C. Ludwig at (615) 843-7460.
S!ncerely, ff I hr K. P. Powers Ac. ting Site Vice President bequoyah Nuclear Plant Enclosures cc (Enclosures):
Mr. D. E. IaBarge, Project Manager U.S. Nuclear Regulatory Commission One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852-2739 I
NRC Resident Inspector Sequoyah Nuclear Plant 2600 Igou Ferry Road Soddy-Daisy, Tennessee 37379-3624 Regional Administrator U.S. Nuclear Regulatory Commission Region II 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323-271)
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4 Enclosure Sequoyah Nuclear Plant (SQN)
Justification For Continued Operation-(JCO)
For Problem Evaluation Report SQPER900372*
1 Pages 6 through 13 contain proprietary information and have been.
deleted from the~ attached JCO. The proprietary information'provides the core loading plans for SQN Unit 2 Cycle 6, Unit 1 Cycle 7, and Unit 2 Cycle 7 supplied by Westinghouse Electric Corporation.
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SITE STANDARD SSP-3.4 CORRECTIVE ACTION REV: 8 PRACTICE Page 29 of 49 No. 50 PER 90O372.
Q Revision 4
PROBLEM EVALUATION REPORT (PER)/
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Pag b ef INCIDENT INVESTIGATION (II) FORM s
CONTINUATION SHEET l uf 13
', > E,g C"Qg@ WPdWCdM NTiO N 4I58
% d i#dMWY Identify the information that is being continued on this sheet (For example: Desc NOTE: Entries made on this sheet shall be signed and dated JCO FOR BQPER 900372 BACKGROUND CAQR SQP 900372 fuel enrichments and cycle average exposures to valuesaddresse greater than those assumed in SQN's design basis documents.
At the time this PER was written, the design basis documents were based on radiation dose associated with a double ended Large Break LOCA having a reactor core burnup not to exceed 650 Effective Full Power Days 4.0% U235 enrichment.
(EFPD) with fuel not to exceed Fuel alterations increased the reactor core burnup level to a maximum of 1000 EFPD with
-U235 enrichments not to exceed 5.0%.
These nuclear fuel changes were made to enable SQN to have longer fuel cycles.
Extending the reactor core burnup to 1000 EFPD and radiation dose to plant equipment than that previous
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calculated in SQNs' design basis documents.
j TECHNICAL EVALUATION J
As discussed above, SQN EQ design basis documents are i
currently based on 650 EFPD burn up with 4.0% U235 fuel enrichment; Reference NE calculation SQN TIRPS-48 Rev 5 and TECH SPEC change 90-12.
As a results of the conditions addressed in SQPER900372, parameters may reach 843 the subject nuclear fuel EFPD with a maximum of 4.2%
enrichment of U235 by the end of tho'U2C6 fuel cycle 4
931021800).
(L36 To asses this condition, the post LOCA reactor ORIGEN computer code (25 910809 001) with 1000 EFP burn up and 4.5% U235 enrichment was used as input to the computer models used in SQN TIRPS-48.
the analysis is provided on sheets 4 and 5. Additional details of The new radiation values were forwarded to NE-EE environmental qualification section.
A review of the all of the equipment remained qualifiable to 4.5% U23510 enrichment nuclear fuel with a reactor core burn up at 1000 EFPD.
See sheet 3.
SITE SSP 3A STANDARD CORRECTIVE ACTION REY: 8 1*RACTICE Page 29 of 49 No.5G PER 9003 ~R PROllLEM EVALUATION REPORT (PER)/
Page S L 2 Revision
.4-INClDENT INVESTIGATION (II) FORM CONTINUATION SIIEET l i N Ud TINUXTi 3@ M[
ai EM; in Ri-ER Identify the information that is being continued on this sheet (For example: Description of Condition)
NOTF.: Entries made on this sheet shall be signed and dated JCO FOR SQPER 900372 (CONTINUED)
CONCLUSION This JCO bounds reactor core designs with U235 average enrichments less than 4.5%.
This includes the U2C6, UIC7, and U2C7 fuel cycles; see sheets 6 thru 13.
NE is currently evaluating the new approved fuel parameters composed of 5.0%
U235 enrichment with a core burn up not to exceed 1000 EFPD.
2-b Calvin W.
Burrell Jr.(j Nuclear Engineer b'%
2.1% 94 Vince A.
Bianco NE-NSSS Supervisor MifE J. Lof ek NE-MN Lead Engineer M g A
Ma'kJ.Qufzynski r
NE-PE l
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ASSESSMENT OF 1000 EPPD WITH 4.5% ENRICHMENT i
The 1000 EFPD radiation values provided by the attached sheets were reviewed to determine if equipment qualification was impacted.
The SQN EQ design is currently based on 650 EPPD.
The qualification doses documented in each each of the EQ binders was compared to I
that shown on the sheets for 1000 EFPD and all of our 10CFR50.49 equipment and cabling remains qualifiable when using these numbers.
Prepared f J/
2/7/7//
Checked haviMflsh
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d ASSEBBMENT OF 1000 EFPD WITH 4.5% U235 ENRICUMENT SQN EQ design basis evaluations,are currently based on 650 EFPD burn up with 4.0% U235 fuel enrichment; Reference NE calculation j
SQN TIRPS-48 Rev 5 and TECH SPEC change 90-12.
As a result of the conditions addressed in SQPER900372, the subject nuclear fuel parameters may reach 843 EFPD with a maximum of 4.2% enrichment of U235 by the end of the U2C6 fuel cycle (L3 6 9310218 00).
To asses this ccndition, the post LOCA reactor core inventories from Oak Ridge National Laboratory (ORNL) ORIGEN computer code (25 910809 001) with 1000 EFPD burn up and 4.5% U235 enrichment was used as input to the computer models used in SQN TIRPS-48.
The results are provided below in rads and are compared to the current design basis radiation levels.
The change in radiation levels are also given in (%).
Room or Area 100 Day Acc.
100 Day Acc.
650 EFPD 0 4.0%
1000 EFPD @ 4.5%
U235 U235 Upper Containment Gamma 2.79+07 3.07+07
+10%
Beta 3.42+08 3.13+08
-8,5%
Lower Containment Gamma 2.43+07 2 73+07
+12%
Beta 3.42+08 3.13+08
-8,5%
Accumulator, Fans, Instrument Rooms Gamma 1.35+07 1.07+07
-21%
Beta 3.42+08 3.13+08
-8.5%
Raceway Gamma 1.64+07 1.21+07
-26%
Beta 3.42+08 3.13+08
-8.5%
Ice Bed Condenser Gamma 1.02+07 1.12+07
+9.8%
1 Beta 3.42+08 3.13+08
-8.5%
Anhulus Gamma 8.15+06 Beta 5.40+05 5.04+05
-6.7%
- Gamma doses in the annulus varies as shown below:
0 0
0 00 thru 280 6,61+06 281 thru 291
= 6.75+06
=
- 291 U 0
0 thru 318 1.06+07 318 thru 328
= 6.75+06
=
U 0
328 thru 360 6.61+36
=
- Region within the annulus that gamma increased, +30%.
It is noted that beta radiation was reduced inside containment as a result of reducing the post LOCA Cs inventory from 50% to 1%,
to be consistent with TID 14844, and the noble gas spectrum change due to the extended burn up.
In the Auxiliary Building, gamma radiation in the air spaces increased 7.4 %.
Gamma dose to equipment fron ECCS piping located in the pipe chase, CCP, RHRP, SIP rooms and the respective heat exchanger rooms increased 52%.
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' ASSESSING EQ' IMPACT USING 1000 EFPD WITH 4.5% U235 ENRICHED FUEL
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On January 4, 1994, NE-NM provided NE-EE an Assessment Of 1000 EFPD With 4.5% U235 Enrichment to determine what impact, if any, continuous operation of the U2C6 fuel cycle will have (n) the EQ analysis, as a result of the adverse' condition addressed in SQPER 900372.
Butch Woodley requested additional information that will provide further explanation in performing this task.
INSIDE CONTA7.NMENT Data in the Assessgent Of 3000 EFPD With 4.5% U235 Enrichment was compared to the current design basis radiation doses (650'EFPDJ@
4.0% U235) inside containment.
The percent difference in1these doses was also provided in the right column.
The impact to the.
EQ analysis can be evaluated by multiplying the radiation values in the EQ Binders (via Location Specific Dose (LSD), Calculations or Radiation QIRs) times the percent delta dose from the upper c
and lower containment values as needed.
For example, if a lower containment ISD Calculation provided a' gamma and beta dose values of 8.4E6 rads and 9.7E7 rads respectively, the impact would be evaluated in the following manner since Gamma increased 12%'and Beta decreased 8.5%:
New Gamma = 1.12 X 8.4E6 rads = 9.41E6 rads New Beta
=.915 X 9.7E7 rads = 8.88E6 rads ANNULUS In the Annulus, gamma and beta radiation are less than-the doses inside containment therefore, the equipment in the Annulus that penetrate containment should inherently be qualified.- If there exist equipment in the Annulus that does not penetrate containment, use the radiation doses provided for the Annulus as they apply.
AUXILIARY BUILDING In the Auxiliary Building, gamma radiation in areas with out ECCS piping increased 7.4 %.
In areas with ECCS piping (ie... pipe chase, CCP, RHRF, SIP rooms and the respective heat exchanger rooms) gamma radiation increased 52%.
The impact to the EQ analysis'would be evaluated in the same manner as shown above inside containment.
New Gamma In Spaces Without ECCS Pipimg = 1.074 X LSD calculation New Gamma In Spaces With ECCS Piping = 1.52 X LSD calculation-
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If you have any questions with regard to this subject matter, consult NM Radiation Protection.
Calvin W.
Burrell Jr.
January 7,1994
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