ML17333B004
| ML17333B004 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 08/14/1997 |
| From: | Rampall I HOLTEC INTERNATIONAL |
| To: | |
| Shared Package | |
| ML17333B003 | List: |
| References | |
| HI-971763, NUDOCS 9708250095 | |
| Download: ML17333B004 (26) | |
Text
IS%58 HOLTEC I N T E R N A T I 0 N A L Hdltec Center, 555 Lincoln Drive West. IVlarfton NJ 08 "53 Telephone (609) 797- 0900 Fax (609) 797 - 0909 DOCUMENTMAME:-
REVIEWANDCER7IHCATlON LOG Responses to RAIon Holtec Report HI-951389 forthe O.C. Cook Spent Fuel Pool HOLTEC DOCUMENTI.D. NUMBER:
971763 HOLTEC PROJECT NUMBER:
70851 CUSTOMER/CUENT:
American Electri Power RFVlSION BLOCK REVISION NUMBER ORIGINAL REVISION I REVISION 2 REVISION 3 AUTHOR &
'ATE REVIEWER &
DATE tNbREyyg
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'Y-wV"8"l APPROVED&
DATE z
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REVISION 4 REVISION 5 REVISION 6 This document conforms to the requirements ofthe design specification and the applicable sections of the governing codes.
Note: Signatures and printed names required in the review block.
A revhion ofthis document willbe ordered by the Project Manager and carried out ifany of its contents is materially affected during evolution of this project. The determination as to the need for revision willbe made by the Project Manager with input from others, as deemed necessary by him.
Must be Project Manager or his designee.
x Distribution:
C:
Client M:
Designated Manufacturer F:
Florida Office Report categoly on the cover page indicates the contractual status ofthis document as A = to be submitted to client for approval I = for client's information N = not submitted externally THE REVISION CONTROL OF THIS DOCUMENTIS BYA
SUMMARY
OF REVISIONS LOS" PLACED BEFORE THETEXT OF THE REPORT.
97G825GG95 97G8<9 POR AOQCK GSGGGM5 P
POa
SUMMARY
OF REVISIONS REVISION 0: This revision contain the followingsections and pages.
TitlePage Review and CertiGcation Log Summary ofRevision Log Table ofContents Figures Appendix A Appendix 8*
14
~ Note: This appendix contains Holtec proprietary information, is therefore not distributed.
This appendix is available for review at Holtec's corporate ofices.
Holtec Report HX-971763 Holtec Project 70851'
TABMOF CONTENTS K,Nil'l
~ae I;0.
Xntroduction 2.0 AEP Request - Description ofAnalysis Methods 3.0 NRC Request I 4.0 NRC Request 2 5.0 NRC Request 3 6.0 References Tables Figures Appendix A Proprietary Appendix B~
'ote:
This appendix contains Holtec proprietary information, is therefore rot distributed.
This appendix is available for review at Holtec's corporate offices.
Holtec Report HI-9? 1763 Holtec Project 70851
1.0 INTRODVCTION This report documents analyses performed. in support of American Electric Power (AEP) personnel responding to a USNRC'Request.for Additional Information (RA@ on the thennal-hydrauEcanaIysis oftheCook Nuclear Plant'spent fuel "pool.(SFP) P}; This report addresses the use ofthe Unit2 uprated reactor power in decay heat calculations.
Sections 2.0 through 5.0 each contain the response to an individual NRC or ABP question.
Where appropriate, references to and comparisons with the result ofthe previous analyses [1} are performed. Not all ofthese four sections contain analyses.
Holtec Report HI-971763 page 1
Holtec Project 70851
2.0 AEP REQUEST - DESCRIPTION OF ANALYSISMETHODS 2.1'ecay Heat Analysis Method All;decay heat calculations. are performed using implementations.of the-OIUGB52 [2J computer code developed at Oak Ridge National Laboratory.
This program has a long history ofuse in the commercial nuclear power industry for both isotope production and thermal power calculations.
The OMGEN2 code is a rigorous isotope generation and depletion code which accurately predicts the products and by-products ofQssion and the resulting heat generation rates.
The decay heat generation rate in the pool consists oftwo components: the decay heat generated by previously discharged fuel assemblies and the decay heat generated by &eshly (recently) discharged assemblies.
The decay heat contribution of previously discharged fuel assemblies changes very little over short periods of time, and is therefore held constant in the analyses.
Because ofthe nature of exponential decay, this simplification is conservative.
The Holtec QA Validated LONGOR [3] computer proem, which incorporates the ORIGEN2 code, is used to calculate this decay heat component.
The decay heat contribution of the freshly discharged 'fuel assemblies changes substantially over even very short periods of tune.
'I'his decay heat contribution is therefore evaluated as time>>
varying.
The Holtec QA Validated BULKTEM[4] computer pro~~
which incorporates the ORIGEN2 code, is used to calculate this decay heat component.
2.2 Bulk SFP Temperature Analysis Method Due to the time-varying decay heat component, the total decay heat is also time-varying.
The bulk SFP temperature is therefore'calculated as a function oftime. The following energy balance is solved to obtain the temperature at each instant in time:
where:
C
= Q
( )-0 ('1)-0 (T)
C is the SFP thermal capacity, Btu/'F T is the bulk SFP temperature, 'F z is the time after reactor shutdown, hr Qc+w) is the decay heat generation, Btu/hr QHx(T) is the SFPCS heat rejection, Btu/hr
~Ap(T) is the evaporative'heat,loss, Btu/hr The evaporative heat loss term includes both evaporative and sensible heat transfer from the surface of the SFP.
The implementation of this term has been benchmarked against actual in-plant test data [5]. The solution of this first-order ordinary differential equation is performed using the BULKTEMpro~ [43 Holtec Report HI-971763 page 2 Holtec Project 70851
Tune-to-Boil Analysis Method I:o11owing a loss offorced cooling, the continuing decay heat load in the SFP willcause the bulk SFP temperature to use.
The equatioa energy balance. which defines this transient phenomena is sitmhrto the.ODE.presented in Section 22, but does not include the.QRz term and does include a time varying SFP thermal capacity, to account for the evaporative water losses.
The time available for corrective action before bulk SFP boiling occurs is determined using the Holtec QA Validated TBOILcomputer program [6].
The decay heat generation and evaporative heat loss terms in this formulation are identical to those defined in Section 2.2, except for the followingtwo differences:
o The decay heat is calculated using the correlations ofUSNRC Branch Technical Position ASB 9-2 I'7] instead ofORIGEH2.
~
No incremental credit is yven for evaporative heat loss at SFP bulk temperatures greater than 170'F.
2.4 Local Temperatures Analysis Method
\\
The decay heat generated by the fuel assemblies stored in the SFP induced a buoyancy driven flow Geld upward through the fuel rack ceHs.
Cooler water is supplied to the bottom ofthe racks cells through the rack-to-wa)l gaps and rack-to-floor plenum.
A computational method for modeling this phenomena is given by Sin~~
et al. I'8). The method presented in the reference has been incorporated into the Holtec QA Validated computer pro~
THERPOOL [9), this is used to perform this analysis.
Holtec Report HI-971763 page 3 Holtec Project 70851
3.0 NRC REQUEST 1
"Withregard to the spent fuel pool (SFP) cooling analyses for the normal refueling scenarios, Case lAand 2'as presented in February 1, 1996 submitta1 are based on the spent &el assunblies dischar ed Gom Unit.1 during Cycle.25A Since Unit 2.
willbe operating at a higher power level than Unit 1 (3588 MWt vs 3250 MVt),
the analyses for Case IA and 2 should be revised based on the spent fuel assemblies discharged trom the Unit 2 reactor during Cycle 20B. Also, Tables 3, 4 and 5, and Figures I, 3, 6 and 8 should be revised to include the results from the above revised analyses."
In addition to the difference in reactor thermal power between Unit 1 and Unit 2, there are differences in the maximum burnup, initial U~q enrichment and &el assembly uranium weight.
These, differences are summarized in the Table 1. Allofthe values in Table I are extracted from Reference 1.
As requested, the cases designated as IA and 2 are re-evaluated using the Unit 2 values for the four parameters presented in Table I. Allinput values are taken from Reference I, and all inputs except those presented in Table 1 are identical to those used in the reference work.
Unlike the oriynal.calculations, however, the thermal transient evaluations performed in ths report utilize version 3.0 of the BULKTEM program tlI].
This newer version of the BULKTEM code contains modification to the evaporative loss correlations [12], which are slightly more accurate than the original correlations, The effects ofthis modification on the results ofthe analysis are minimal.
The results ofthe maximum SFP bulk temperature analyses are presented in Table 2, where they are also compared with the previously reported values (I]. Temperature profiles for each case are presented in Figures 1 and 2. Net decay heat load and evaporative heat loss pro6les for each case are presented in Figures 3 and 4.
As expected, the maximum bulk SFP temperatures are marginally higher than previously reported.
The results ofthe bulk temperature analysis are propagated through to the time-to-boil and local temperature
- analyses, the results of which are presented and compared with the corresponding previously reported values [I]in Tables 3 and 4, respectively.
As expected, the minimum time-to-boil is slimly less than previously reported, and the maximum evaporation rate and local temperatures are slightly higher than previously reported.
Holtec Report HX-971763 page 4 Holtec Project 70851
4.0 NRC REQUEST 2 "In.the analyses for the scenario ofback-to-back Rll core discharge withtwo SFF
'ooling trains (Case,3),"'pent fuel assembEes Rom Unit 2;are assutned,to be discharged m three:groups'each with. a diQerent burnup:vaIue= Provide curves to show the decay heat rates as a function oftime generated in the SFP Rom each of these youps."
Figure S presents the decay heat profiles for each of the three groups of the Rll core discharge batch for Case 3.
As expected, the decay heat generation rate and the reactor exposure are directly proportional.
Holtec Report HI-971763 page 5 Holtec Project 70851
~
5.0 NRC REQUEST 3 "In the response (A 4) to the staQ's RAX presented in Pebtuary 1,'1996 submittal, decay heat generation rates for spent fuel assemblies Rom each previous discharge cycle are provided Decay heat generation rates Rom. these previously discharged spent fuel assemblies are also provided in the Attachments 2 and 3 to the letter dated August 1, 1996. However, decay heat generation rates presented in August 1, 1996 submittal deviate significantly Rom that presented in Pebruaty 1, 1996 submittal. Provide clarification and justification for this discrepancy."
The February 1, 1996 submittal is in response to an NRC RAI on Holtec Report HI-941183. The August 1, 1996 submittal is in response to an NRC RAI on Holtec Report HI-951389.
A discussion of these diQ'erences between these decay heat generation rates has previously been provided in response I.C ofthe August 1, 1996 submittal [10].
Holtec Report HI-971763 page 6 Holtec Project 70851
6.0 REFEIU2lCES
[1]
"Updated Thermal-Hydraulic Analysis of Spent Nuclear Fuel Pool,.- Donald C. Cook Nuclear Plant" Holtec Report HI-951389, Revision'.-
[2]
A.G. CrofE "ORNL Isotope Generation and Depletion, A User's Manual for the ORIGEN2 Computer Code," ORNL/TM-7175, RSIC/CCC-371, Oak Ridge National Laboratory, July 1980.
[3]
"QADocumentation forLONGOR v1.0," Holtec Report HI-951390, Revision 0.
[4]
"QADocumentation forBULKTEMv2.0," Holtec Report HI-951391, Revision 0.
[5]
Wang, Yu, "Heat Loss to the Ambient trom Spent Fuel Pool: Correlation ofTheory with Experiments," Holtec Report HI-90477.
[6]
"QADocumentation for TBOILv1.6," Holtec Report HI-92832, Revision 2.
[7]
USNRC Branch Technical Position ASB 9-2, "Residual Decay Energy for Linet Water Reactors forLong Term Coolino " Revision 2, July 1981.
[8]
Sin+~, K.P. et. al., 'Method for Computing the Maximum Water Temperature in a Fuel Pool Containing Spent Nuclear Fuel", Heat Transfer Engineering, Volume 7, Number 1-2, pp. 72-82, 1986.
[9]
"QA Validation for THERPOOL v 1.2", Holtec Report HI-87120, Revision 2.
[10]
Letter Gom E.E. Fitzpatrick (AEP) to USNRC, Docket Numbers 50-315 and 50-316, Document ID AEP:i&C.C:1202B, Attachment 1, Response 1.C.
fl1]
"QADocumentation for BULKTEMv3.0", Holtec Report Hl-951391, Revision 1.
[12]
"An Improved Correlation for Evaporation from Spent Fuel Pools," Holtec Report HI-971664, Revision 0.
Holtec Report HI-971763 page 7 Holtec Project 70851
T P
TABLE 1 DIFFERENCES BEWVEENUNITIANDUNIT2 NORMALDISCHARGES Parameter Reactor Thermal Power (MVt)
Maximum Average Burnup (MWdMTU)
InitialU~ Enrichment (%)
Assembly Uranium Weight (kg)
UnitI Value 3,250 52,200 3.50 461 Qmt 2 Valee 3,588 68,400 4.00 410 Holtec Report H1-971763 Holtec Project 70851
TABLE2 RESULTS OF MAXIMUMBULKSPP TEMPERATURE ANALYSES Parameter Current Results (Unit2)
Previous Results (Unit 1)
Case IA Magnum SFP Temperature Coincident Time After Shutdown Coincident Net Heat Load to HXs Coincident Evaporative Heat Loss Maximum SFP Temperature Coincident Time After Shutdown Coincident Net Heat Load to HXs Coincident Evaporative Heat Loss 156.56'F 138.0 hrs 28.50x10 Btu/hr 2.79x10 Btu/hr Case 2 129.84'F 130.0 hrs 30.75x10 Btu/hr 0.99xlO Btu/hr 154 37'F 138.0 hrs 27.19xl0 Btu/hr 2.35x10 Btu/hr 128.68oF 131.0 hrs 29.32x10 Btu/hr 0.57xl0 Btu/hr Holtec Report HI-971763 Holtec Project 70851
TABLK3 RESULTS OF BOILINGTMFS ANALYSES Parameter Current Results (Unit2)
Previous Results (Unit I)
Case lA Time to Start ofBoiling Maximum Evaporation Rate Time to Start ofBoiling Maximum Evaporation Rate 8.53 hrs 66.83 gpm Case 2 12.11 hrs 67.30 gpm 9AS hrs 63.35 gpm 13.37 hrs 63.64 gpm Holtec Report HI-971763 Holtee Project 70851
TABLE4 RESULTS OF MAXIMUMLOCALTEMPERATURES ANALYSIS (Case.IA Only)
Parameter Current Results (Unit 2)
Previous Results (Unit 1)
No Blocka~e Maximum Local Water Temperature Maximum Fuel Clad Temperature Maximum Local Water Temperature Maximum Fuel Clad Temperature 166 O' 216.3'P 50% Blocha e
226. lop 256.8'P 163.6'P 214.5'P 223 5'F 254 3oP Holtec Report HI-971763 Holtec Project 70851
'V
~ ~
FlGURE 1: Spent Fuel Pool Bulk Wateg Temperature Profiles Case 1A, Normal Discharge, 1 Cooling Train 160 155 150 0
1<5 E
~
140 63 135-130 0
50 100 150 200 250 300 Time After Reactor Shutdown (hrs) 350 400 450 500 Hoitec Report Hl-971763 Holtec ProJect 70851
FfGURE 2: Spent Fuel Pool Bulk Water Temperature Profiles Case 2, Normal Discharge, 2 Cooling Trains 130 128 C
126 LL 124 Q
122 L
~~
120 Ql 118 116 114 50 100 150
. 200 250 300 Time After Reactor Shutdown (hrs) 350 400 450 500 Holtec Report Hi-971763 Holteo pro/cot 70851
FIGURE 3: Spent Fuel Pool Decay Heat Load and Loss Profiles Case 1A, Normal Discharge, 1 Cooling Train 35.0E46 30.0E+6 M
4I Vl 0
C Clx'a Ccf'0 tl$
O C$
x C
Qn 25.0E46.-
20.0E+6
'15.0E+6 10.0E46 Net Decay Heat Load 5.0E+6 Evaporative Heat Loss 000.0E+0 50 100 150 200 250 300 Time After Reactor Shutdown (hrs) 350 400 450 500 Holtec Report Hl-9?1763 Holtec Project 70851
\\
~
FIGURE 4: Spent Fuel Pool Decay Heat Load and Loss Profiles Case 2, Normal Discharge, 2 Cooling Trains 35.0E46 30.0E+B 3
25.0E+6
~
~
g 20.0E+6 '
o 15.0E+B 5
10.0E4B A
z 5.0E+B-Net Decay Heat Load 000.0E40 50 100 150 Evapora(ive Heat Loss 200 250 300 Time After Reactor Shutdown (hrs) 350 400 500 Hoitec Report Ht-971763 Hottec ProJect,70851
r I
~
FIGURE 6: Decay Heat Generation Rate for Each Discharge Batch ln the Full Core Back-to-Back Discharge Case 3 15.0E+6 14.0E+6 Three Exposure Cycles 13.0E+6 Two Exposure Cycles Pg 12.0Et6 PLc 11.0E+6 10.0E+6 6
9.0E+6 n
8.0E+6 One Exposure Cycle 7.0E<6 6.0E+6 50 100 150 200 250 300 350 Tlrne After Second Reactor Shutdown (hrs) 400 450 500 Holtec Report Hl-971763 Holtec Project 70851
r C
I
ATTACHMENT 2 TO AEP:NRC:1202D
RESPONSE
TO QUESTION 4 REQUEST FOR ADDITlONAL INFORMATION REGARDING REFUELING OPERATIONS DECAY TIME
Attachment 2 to AEP:NRC:1202D Page 1
NRC uestion 4.0 "Is full-core offload a current practice during normal refueling?"
Res onse to uestion 4.0 Current practice is to perform full core offloads.