ML20211J233
| ML20211J233 | |
| Person / Time | |
|---|---|
| Site: | Duane Arnold  |
| Issue date: | 10/03/1997 |
| From: | IES UTILITIES INC., (FORMERLY IOWA ELECTRIC LIGHT |
| To: | |
| Shared Package | |
| ML20211J229 | List: |
| References | |
| NUDOCS 9710080040 | |
| Download: ML20211J233 (8) | |
Text
t 4
Attact. ment 3 to NO 971$78
- PageI i
PROPOSED CilANGE fRTS 2961 TO Tile DUANE ARNOLD ENERGY CENTER OPERATING LICENSE
)
'lhe holders oflicense DPR 49 for the Duane Arnold Energy Center propose to amend l
Operating License by deleting the following current page and replacing it with the l
attached, new page. The Affected Page is given below, i
AFFECTED PAGE l
l Operating License page 2 i
l
SUMMARY
OF CilANGES:
Eagt Descrintion of Channe OL 2 Revise Operating License item 2.B (2) to allow refueling activities pursuant to letters dated March 26,1993 and October 3,1997.
9710000040 971003 DR ADOCK 050003 1 -
9,
G.
The issuance of this operating license will not be inimical to the common defense and security or to tne health and safety of the public; H.
After weighing the environmental, economic, technica4, and other benefits of the facility against environmental costs and considering available alternatives, the issuance of Facilit operating License No. DPR-49 is in addordance with 10 CFR Part 50, Appendix D, of the Commission's regulations and all applicable requirements of said Appendix D have been satisfied; 1.
The receipt, possession, and use of source, by-product and special nuclear material as authoriaed ley this license will be in accordance with the Commission's regulations in 10 CFR Part 30 and 70, including 10 CFR section 30.33, 70.23 and 70.31.
Revision to OL 2.
Facility Op rating License No. DPR-49 is hereby issued Amendment 0198 to IE3 Utilities Inc., Central Iowa Power Cooperative 05/13/94 (CIPCO) and Corn Belt Power Cooperative (Corn Belt) to read as follows:
Revision to OL A.
This license applies to the Duane Arnold Energy Amendment fl98 center, a boiling water reactor and associated equipment the 05/13/94 f acility), owned by the licensees and operated by IES Utilites Inc.
The facility is located on the licensees' site near Palo in Linn County, Iowa. This site consists of approximately 500 acres adjacent to the Cedar River and is described in the " Final Saf ety Analysis Report" as supplemented and amended (Supplements 1 through 14) and the Environmental Report as supplemented and amended (Supplements 1 through 5).
B.
Subject to the conditions and requirements incorporated herein, the Commission hereby licenses:
Reveion to OL (1)
IES Utilities Inc., pursuant to Section 104b of the Amendment #198 Act and 10 CFR Part 50, " Licensing of Production and 05/13/94 Utilization Facilities," to possess, use, and operate the f acility and CIPCO and Corn Belt to possess the facility at the designated location in Linn County, Iowa, in accordance with the procedures and limitations set forth in this license; June 1992 and as Supplemented by letter dated March 26, 1993 Revision to OL (2)
IES Utilities Inc., pursuant to the Act and 10 CFR Part Amendment fl98 70, to receive, possess and use at any time special 05/13/94 nuclear material as reactor fuel, in accordance with the Revision to OL limitations for storage and amounts required for reactor Amendment 89 operation, as described in the Updated Final Safety 6/3/75 Analysis Report, as supplemen nd amended as of Jung nt 1
Q 02/02/94
/o/3/n RTs-a
$ to NG 971$78 Pagei 1
SAFETY ASSESSMENT l.
INTRODUCTION I
By letter dated October 3,1997, IES Utilities Inc submitted a request for revision to the Operating License for the Duane Arnold Energy Center (DAEC). The proposed change supplements the thermal hydraulle analysis submitted as Reference 1 on March 26,1993. Specifically, this amendment request introduces three new refueling scenarios which will allow fuel movement to begin as soon as 60 hours6.944444e-4 days <br />0.0167 hours <br />9.920635e-5 weeks <br />2.283e-5 months <br /> after shutdown instead of the 120 hour0.00139 days <br />0.0333 hours <br />1.984127e-4 weeks <br />4.566e-5 months <br /> decay time required by Reference 1 and Operating License Amendment 195, Reference 2.
Case A of Attachment 5 to NG 97-1578 assumes a planned (i.e., follows 18 -
months of power operation) full core ofiload with one FPCCU train running before Residual Heat Removal Supplemental Fuel Pool Cooling (RHR SFPC)is initiated. RHR SFPC is assumed to be in service when SFP temperature reaches 120'F. RHR SFPC provides cooling to the Spent Fuel Pool (SFP) and reactor cavity by taking suction from the Residual Heat Removal (RHR) Shutdown Cooling system piping and diverting a portion of flow to the SH. The transfer j
canal gates are assumed to be open and water is able to flow from the SFP to the flooded reactor cavity. FPCCU is conservatively assumed to be secured when RHR SFPC is used. This assumption is made for analysis purposes only as both systems can be operated together to remove decay heat.
Case B of Attachment 5 to NG 971578 is identical to Case A ex:ept it assumes a planned full core ofiload with two FPCCU trains running prior to initiation of RHR SFPC, Case C of Attachment 5 to NO-971578 assumes an unplanned full core offload with two FPCCU trains running prior to initiation of RHR SFPC. RHR SFPC is assumed to be in service when SFP temperature reaches 120'F. This scenario consists of a normal 36 day refueling outage followed by 45 days of full power operation and a subsequent unplanned transfer of the entire core to the SFP. The analysis conservatively assumes the recently loaded fresh fuel has undergone 18
- months of exposure even though it has been in the reactor for only 45 days.
The loss of forced cooling event assumes a cask pit isolation gate failure occurs when the SFP bulk temperature is at the calculated maximum. The minimum time to take action following a loss of forced cooling with cask pit isolation gate failure event in order to prevent fuel in the SFP from being uncovered is hereafter teferred to as " minimum time to action".
o 4 to NO 971578 Page 2 The three cases analyzed in Attachment 5 to NO.971578 evaluate the control and removal of decay heat generated by full core discharges. During a partial core discharge or "shuflie", the rate of heat transfer to the SFP as well as the total decay heat transferred to the SFP would be less than that expected for a full core discharge. Therefore, the three cases analyzed in Attachment 5 to NO 971578 are considered to bound a fuel shuffle scenario at DAEC.
I ne computational fluid dynamics analysis performed in Attachment 5 to NO.97-1578 has been performed using an industry standa~1 FLUENT flow and heat transfer modeling program. This program was not used in the thermal hydraulle analysis submitted as Reference 1. Therefore, the improved modeling capability of the FLUENT program removes some of the excess conservatism that was present in the Reference I analysis. IES Utilities understands the NRC has reviewed and approved computational fluid dynamics analyses submitted by several other licensees which used FLUENT.
2.
ASSESSMENT The following table compares the maximum bulk SFP temperatures, maximum local water and fuel cladding temperatures, and loss of forced cooling with cask j
pit isolation gate failure results calculated for Cases 3 and 4 of Reference 2 (Amendment 195) and the three new Cases A, B and C proposed in Attachment 5 to NO 971578. The shaded columns represent the bounding cases.
For simplicity, only the bounding scenarios will be compared, it can be noted that the proposed Case C (which assumes fuel movement begins 60 hoes after shutdown) results in lower maximum bulk SFP, local water and local fuel clad temperatures than those previously calculated for Case 3 of Amendment 195 (which assumes fuel movement begins 120 hours0.00139 days <br />0.0333 hours <br />1.984127e-4 weeks <br />4.566e-5 months <br /> after shutdown). This improved thermal perfonnance is attributable to the use of RilR-SFPC for Case C versus use of the FPCCU system for Case 3.
J to NO.97 l$78 Page 3 Plant Amendment 195 RTS 296 Parameter Case 3 Case 4 Case A Case B Casec Maximum SFP Temperatures and in Core lloid Time Results l
Maximum bulk SFP 164.61 163.2 154.31 154.30 l $9.87 <
l temperature (*F)
Max. temp at # hours 190 189 124 124 124 aller shutdown (*F)
Maximum heat load
.18.73" 18.37 20.87 20.87 22.54 m 6
(10 Blu/hr)
Local Water and Fuel Cladding Temperatures Results Max. local water temp 216.6 a not calculated for non bounding 171.749
('F) scenarios Max, local fuel clad 264.4-not calculated for non bounding 230.46 :
temp ('F) scenarios Loss of Forced Cooling Results Minimum time to action 5.5.
5.7 5.0 5.0 4.5-i (hours)
Boil otTrste (gpm) 43.11.
42.14 48.82 48.82
$2.78 Maximum Bulk SFp Temperatute Results in the above table, the maximum bulk SFP temperature for the bounding case proposed in Attachment 5 to NO 971578 (Case C)is less than that calculated for the bounding scenario of the Reference 1 analysis (Case 3),i.e.,159.87'F versus 164.61'F. This maximum SFP temperature is below the temperature associated with the onset of boiling and therefore meets the guidance of Section 9.1.3 of Standard Review Plan (SRP) which addresses providing adequate cooling for the postulated SFP inventory under full core ofiload conditions, it can also be seen that the pr,oposed Case C maximum heat load of 22.54x 10' Btu /hr exceeds the 18.73x10 Btu /hr previously calculated for Case 3 of the Refeience 1 analysis. As supported by the analysis of Attaciunent 5 to NO 97-1578, the RIIR-SFPC is capable of adequately removing the heat load of the proposed Case C.
Maximum Local Water And Fuel Clad Temneratures
~
in the above table, the maximum local water temperature and maximum local fuel clad temperature for the proposed Case C are significantly below those temperatures previously calculated per the Reference 1 analysis.
f to NO.971578 l' age 4 Minimum Time To Action Follmvine 1.oss Of Forced Cooline With Cask Pit Isolation Gate Failure As stated in Amendment 195 (Reference 2), the DAEC will use Emergency Service Water (ESW) as the Seismic Category I makeup source in the event of a loss of forced cooling with cask pit isolation gate failure. In the above table, the minimum time to take action before SFP fuel is uncovered has decreased from 5.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> in the Reference I analysis, to 4.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> in the proposed Case C. This l
represents a slight impact on safety, however, it is estimated that it will take no more than 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> to provide ESW makeup to the SFP. Therefore, the calculated minimum time to action of 4.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> for the proposed case is acceptable and will allow enough time to provide ESW makeup to the SFP before fuel is uncovered.
It can also be seen that the proposed Case C results in a slightly greater boil off rate,i.e., $2.78 gpm. A special test of the ESW flow to the SFP conducted at the DAEC on September 26,1996 demonstrated an ESW flow of 59.75 gpm, which is in excess of the 52.78 gpm required. As discussed in Amendment 195, makeup to the SFP can also be supplied from fire water hoses.
Use of RIIR SFPC The three cases analyzed in Attachment 5 to NO 971578 evaluate the control and removal of decay heat generated by full core discharges. During a partial shufile discharge or "shuflic", the rate of heat transfer to the SFP as well as the total decay heat transferred to the SFP would be less than that expected for a full core discharge. It is not anticipated, therefore, that initiating RilR SFPC would be required for a core shuffle. Ilowever, RilR SFPC could be initiated ifit was detennined that the FPCCU system was not adequately removing decay heat or if the FPCCU system was removed from service (e.g., maintenance). The decay heat removal capacity of RilR SFPC is larger than that of the FPCCU system, and would be more than adequate to remove the SFP heat generated during a core shuffle.
DAEC procedures require the use of FPCCU and/or RilR SFPC to maintain SFP temperatures below 150*F. For a fuel shuille, the DAEC will control SFP temperatures using SFP heatup rates and decay heat generation curves to ensure RilR SFPC is initiated if needed to preclude SFP temperature from exceeding the maximum SFP temperature calculated for Case C of Attachment 5 to NO 97-1578,i.e.,159'F. For a full core ofiload, DAEC procedures will be changed to direct operators to ensure RliR SFPC is in service prior to SFP temperature exceeding 120*F, thereby precluding SFP temperature from exceeding 159'F.
I to NO 971578 Page$
Use of RilR to provide SFP cooling wu reviewed and approved per the original DAEC Safety Evaluation Report (SER). Procedural controls are in place to allow RilR in Supplemental Fuel Pool Cooling mode when the reactor is in cold shutdown. Procedural controls are also in place to ensure the RilR SFPC is available for use while discharging fuel to the SFP.
As demonstrated in Attachment 5 to NO 971578, the maximum SFP temperature does not occur until afler all the fuel has been transferred to the SFP. Therefore, it is allowable to take less than ten minutes to transfer an individual assembly provided that it takes at least 61.3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> to transfer the entire core. As p.Jt of implementation of this Operating License change, procedural controls will be put in place to ensure fuel discharge does not begin prior to 60 hours6.944444e-4 days <br />0.0167 hours <br />9.920635e-5 weeks <br />2.283e-5 months <br /> aner shutdown and full core ofiload is not completed prior to 121.3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> after shutdown.
i j
13ased upon the above assessment, we conclude that this request is acceptable.
4 Anachment 4 to NO.97 1578 Page1 ENVIRONMENTAL, CONSIDERATION 10 CFR Section $1.22(c)(9) identifies certain licensing and regulatory actions which are eligible for categorical exclusion from the requirement to perfonn an environmental assessment. A proposed amendment to an operating license for a facility requires no environmental assessment if operation of the facility in accordance with the proposed amendment would not: (1) involve a significant hantrds consideration; (2) result in a significant change in the types or significant increase in the amounts of any emuents that may be released offsite; and (3) result in a significant increase in individual or cumulative occupational radiation exposure. IES Utilities Inc. has reviewed this request and determined that the proposed amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR Section $1.22(c)(9). Pursuant to 10 CFR Section $1.22(b),
no environmental impact statement or environmental assessment needs to be prepared in connection with the issuance of the amendment. The basis for this determination follows:
liash The ci.ange meets the eligibility criteria for categorical exclusion set forth in 10 CFR Section St.22(c)(9) for the following reasons:
1.
As demonstrated in Attachment 1 to this letter, the proposed amendment does not involve a significant hazards consideration.
2.
The proposed amendment includes changes which allow initiation of core omond as soon as 60 hours6.944444e-4 days <br />0.0167 hours <br />9.920635e-5 weeks <br />2.283e-5 months <br /> aller shutdown. Attachment 5 shows maximum bulk SFP temperatures, minimum time to action following loss of forced cooling with cask
)
pit isolation gate failure, and local water and fuel clad temperatures will remain within acceptable limits and will not initiate bulk pool boiling, challenge fuel rod integrity orjeopardize the structural integrity of the SFP. Thus, there will be no significant change in the types or significant increase in the amounts of any emuents that may be released offsite.
3.
The proposed amendment includes changes which allow initiation of core omoad as soon as 60 hours6.944444e-4 days <br />0.0167 hours <br />9.920635e-5 weeks <br />2.283e-5 months <br /> aller shutdown. Attachment 5 shows maximum bulk SFP temperatures, minimum time to action following loss of forced cooling with cask pit isolation gate failure, and local water and fuel clad temperatures will remain within acceptable limits and will not initiate bulk pool boiling, challenge fuel rod integrity orjeopardize the structural integrity of the SFP. Thus, there will be no significant increase in either individeal or cumulative occupational radiation exposure.
M