ML20023B279
| ML20023B279 | |
| Person / Time | |
|---|---|
| Site: | Seabrook  |
| Issue date: | 12/20/1982 |
| From: | Devincentis J PUBLIC SERVICE CO. OF NEW HAMPSHIRE, YANKEE ATOMIC ELECTRIC CO. |
| To: | Knighton G Office of Nuclear Reactor Regulation |
| References | |
| SBN-407, NUDOCS 8212270188 | |
| Download: ML20023B279 (9) | |
Text
.
PUEBLIC SERVICE ssAs m swiw
%s omw.
Companyof New Hampshre 1671 Worceaer Road Framinoham, Massasosetts 01701 (6171 - 872 - 8100 December 20, 1982 SBN-407 J
T.F. B7.1.2 Unitea States Nuclear Regulatory Commission Washington, D. C. 20555 Attenticn:
Mr. George W. Knighton, Chief Licensing Branch No. 3 Division of Licensing
References:
(a) Constructica Permits CPPR-135 and CPPL--136, Docket Nos. 50-443 and 50-444 (b) USNRC Memorandum, dated October 14, 1982, " Notice of Meeting Regarding Open Items in the Safety Review,"
L. L. Wheeler to J. D. Kerrigan
Subject:
Response to Open Items; (SRP 4.2; Core Performance Branch)
Dear Sir:
In response to the open items discussed at the referenced meeting, we offer the following:
Item:
Confirm that cladding collapse is predicted to occur subsequent to the anticipated lifetime of the fuel.
Response: Westinghouse has performed an anclysis of the Seabrook fuel using the generic methods given in NRC approved Westinghouse Topical Report, WCAP-8377, " Revised Clad Flattening Model " This analysis demonstrated that for all fuel regions in the Seabrook initial core, cladding collapse is not predicted to occur until well in excess of 40,000 effective full power hours (EFPH) which is well in excess of the anticipated lifetime of the fuel.
Iteu:
Provide supplerental ECCS calculations which evaluate the potential impact of using fuel rod models presented in draf t NUREG-0630,
" Cladding Swelling and Rupture Models for LOCA Analysis."
Responee: Attachment 1 provides the supplemental ECCS calculations for Seabrook Station.
Item:
Applicant to demonstrate conformance to Appendix A of Standard Review Plan Section 4.2, " Evaluation of Fuel Assembly Structural l
Response to Externally Applied Forces to Standard Review Plan l
Section 4.2."
CK ohhh PDR
United States Nuclear Regulatory Commission December 20, 1982 Attention:
Mr. George W. Knighton Page 2 Response: Seabrook is encompassed by the response spectrum given in WCAP-94Gl-P-A, " Verification 7ecting and Analysas of the 17 x 17 Optimized Fuel Assembly." However, 17 x 17 Incocal grid (or
" Standard") fuel assemblies are intended to be used for the initial core. Westinghouse performed a sensitivity study of the impact of various mixed core loading configurations of optimized and standard fuel for the plants encompassed by UCAP-9401-P-A, (MS-EPR-2573, E.
P. Rahe, Westinghouse to J. R. Miller, NRC, dated March 19, 1982).
Included in this study was a configuration of all standard fuel.
This study demonstrated that for a full core of standard fuel grid, loads well below the allowable are obtained.
Very truly yours, YANKEE ATOMIC ELECTRIC COMPANY G' k*v'Y y
-v J. DeVincentis Project Manager ALL/fsf cc: Atomic Safety and Licensing Board Service List
?
t l
l
)
ATTACHMENT 1 SEA 8 ROOK - SUPPLEMENTAL ECCS CALCULATIONS A.
Evaluation of tne potential impact of using fuel rod models presented in draft NUREG-0630 on tne Loss of Coolant Accident (LOCA) analysis for Seaorook Station.
Tnis evaluation is based on the limiting break LOCA analysis identified as follows:
BREAK TYPE DOUdLE ENDED COLD LEG GUILLOTINE BREAK DISCHARGE COEFFICIENT 0.3 WESTINGHOUSE ECCS EVALUATION MODEL VERSION February 1978-CORE PEAKING FACTOR 2.32 HOT R00 MAXIMUM TEMPERATURE CALCULATED FOR THE BURST REGION OF THE CLAD l'908 *F = PCT8 ELEVATION -
6.0 Feet HOT R00 MAXIMUM TEMPERATURE CALCULATED FOR A NON-RUPTURED REGION OF THE C;AD 1965
- F = PCTg ELEVATION 7.5 Feet CLAD STRAIN DURING BLOWDOWN AT THIS ELEVATION 2.45-Percent MAXIMUM CLAD STRAIN AT THIS ELEVATION
-2.45 Percent Maximum temperature for tnis non-burst node occurs wnen the core reflood rate is greater than 1.C inch per second and reflood heat transfer is caseo on the FLECHT calculation.
AVERAGE HOT ASSEMBLY R00 BURST ELEVATION 6.0 Feet HOT ASSEMBLY BLOCKAGE CALCULATED 46.6 Percent 3204Q:1/111582
7 1.
BURST N0DE The maximum potential impact on the ruptured clad node is expr.essed in letter NS-TMA-2174 in terms of the change in the peaking factor limit (FQ) required to maintain a peak clad temperature (PCT) of 2200*F and in terms of a change in PCT at a constant FQ.
Since the clad-water reaction rate increases significantly at temperatures above.2200*F, individual effects (such as APCT due to changes in several fuel rod models) indicated here may not accurately apply over large ranges, but a simultaneous change in FQ which causes the PCT to remain in the n.eighborhood of 2200.*F justifies use of this evaluation procedure.
From NS-TMA-2174:
For the Burst Node of the Clad:
0.01 AFQ > ~ 150*F BURST N0DE APCT Use of the NRC burst model and the revised Westinghouse burst model could require an FQ reduction of 0.027 The maximum estimated impact of using the NRC strain model is a required FQ reduction of 0.03.
Therefore, the maximum penalty for the Hot Rod burst node is:
aPCT1 = (0.027 +.03) (150*F/.01) = 855*F Margin to the 2200*F limit is:
292
- F APCT2 = 2200.*F - PCTB=
The FQ reduction required to maintain the 2200*F clad temperature limit is:
3204Q: 1/110182
3
\\
r aFQB = (aPCT1 - APCT ) ( 50 F }
2 l
- (855 - 292) ( O)
=.0375 (but not less than zero).
2.
NON-BURST N0DE The maximum temperature calculated for a non-burst section of clad typically occurs at an elevation above the core mid-plane during the core reflood phase of the LOCA transient The potential impact on that maximum clad temperature of using the NRC fuel rod models can be estimated by examining two aspects of the analyses.
The first aspect is the change in pellet-clad gap conductance resulting from a differ-ence in clad strain at the non-burst maximum clad temperature node elevation.
Note that clad strain all along the fuel rod stops after clad burst occurs and use of a different clad burst model can change the time at which barst is calculated.
Three sets of LOCA analysis results were studied to establish an acceptable sensitivity to apply generically in this evaluation.
The possible PCT increase resulting from a change in strain (in the Hot Rod) is +20*F per percent decrease in strain at the maximum clad temperature locations.
Since the clad strain calculated during the reactor coolant system blowdown phase of the accident is not changed by the use of NRC fuel rod models, the maximum decrease in clad strain that must be considered here is the difference between the " maximum clad strain" and the " clad strain at the end of RCS blowdown" indicated above.
l Therefore:
) (MAX STRAIN - 8 LOWDOWN STRAIN) aPCT3*
.01 ain
=(
) (.0245
.0245) l
= 0.0 l
l l
3234Q: 1/110182
e-The second aspect of-the analysis that can increase PCT is the flow blockage calculated.
Since the greatest value of blockage indicated by the NRC blockage model is 75 percent, the maximum PCT increase can be estimated by' assuming that the current level of blockage in the analysis (indicated above) is raised to 75 percent and then applying "an appropriate sensitivity formula shown in NS-TMA-2174.
Therefore, aPCT4 = 1.25'F (50 - PERCENT CURRENT BLOCKAGE)
+ 2.36*F (75-50)
= 1.25 (50 - 46.6) + 2.36 (75-50)
= 63.25 *F If PCTN occurs when the core reflood rate is greater than 1.0 inch per second aPCT4 = 0.
The total potential PCT increase for the non-burst node is then aPCT5 = APCT3 + APCT4 = 0.0 Margin to the 2200*F limit is aPCT6 = 2200*F - PCTN = 235.0 The FQ reduction required to maintain this 2200*F clad temperature limit is (from NS-TMA-2174)
AFQN = (aPCT5 - APCT ) (10 F T) 6 f
AFQN = -0.235 but not less than zero.
> 0.0 l
l 3204Q: 1/102982
b The peaking factor reduction required to maintain the 2200*F clad temperature limit is therefore the greater of AFQ and aFQ '
B N
1 or; aFQPENALTY = 0.0375 l
B.
The effect on LOCA analysis results of using improved analytical and modeling techniques (which are currently approved for use in the Upper Head Injection plant LOCA analyses) in the reactor coolant system blowdown calculation (SATAN computer code) has been quantified via an analysis which has recently been submitted to the NRC for review.
Recognizing that review of that analysis is not yet complete and that the benefits associ-ated with those model improvements can change for other plant designs, the NRC has established a credit that is acceptable for this interim period to he.lp offset penalties resulting from application of the NRC fuel rod models.
That credit for two, three and four loop plants is an increase in the LOCA peaking factor limit of 0.12, 0.15 and 0.20 respectively.
C.
The peaking factor limit adjustment required to justify plant operation for this interim period is determined as the appropriate aFQ credit iden-tified in section (B) above, minus the aFQPENALTY calculated in section (A) above (but not greater than zero).
FQ ADJUSTMDIT =
.2
-.0375
> 0.0 3204Q: 1/10 982
i DOCUMENT
SUMMARY
Document Id:
2168D Document Name:
SRP 4.2 OPEN ITEMS Operator:
fsf Author:
LEGENDRE, A. L.
Comaents:
.16.CO.
12/20 STATISTICS OPERATION DATE TIME WORKT'M\\.
KEYSTROKES j
Created 12/20/82 13:57
- 09 2158 Last Revised 12/20/82 14:59
- 01 273 Last Printed 12/20/82 15:03 Last Archived
/ /
onto Diskette Total Pages:
2 Total Worktime:
- 10 Total Lines:
72 Total Keystrokes:
2431 Pages to be printed 2
Notify U22 on system VOL1.
This Document Will Be DELETED:
.M-
a.---..
ASLB SERVICE LIST Philip Ahrens, Esquire Assistant Attorney General Department of the Attorney General Augus ta, ME 04333 l
Representative Beverly Hollingworth Coastal Chamber of Commerce 209 Winnacunnet Road Hampton, NH 03842 William S. Jordan, III, Esquire Harmon & Weiss 1725 I Street, N.W.
Suite 506 Washington, DC 20006 E. Tupper Kinder, Esquire Assistant Attorney General Office of the Attorney General 208 State House Annex Concord, NH 03301 Robert A. Bachas, Esquire 116 Lowell St cet P.O. Box 516 Manchester, NH 03105 Edward J. McDermott, Esquire Sanders and McDermott Professional Association 408 Lafayette Road Hampton, NH 03842 I
Jo Ann Shotwell, Esquire Assistant Attorney General Environmental Protection dureau Department of the Attorney General One Ashburton Place, 19th Floor Boston, MA 02103 1
.