ML20031E741
| ML20031E741 | |
| Person / Time | |
|---|---|
| Site: | Clinton  |
| Issue date: | 10/09/1981 |
| From: | Wuller G ILLINOIS POWER CO. |
| To: | John Miller Office of Nuclear Reactor Regulation |
| References | |
| L32-81(10-09)-6, L32-81(10-9)-6, U-0305, U-305, NUDOCS 8110160374 | |
| Download: ML20031E741 (4) | |
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ILLIND/S POWER 00MPANY 49 3
(79_99y_g 500 SOUTH 27TH STREET, DECATUR,11LINOIS 62525 October 9,1981 g
1 Mr. James R. Miller, Chief Standardization & Special Projects Branch E
J.
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Division of Licensing 5 WTI S 1'9b 1
Office of Nuclear Reactor Regulation g.,
so.wim m U. S. Nuclear Regulatory Commission
_,,Jj Washington, D. C.
20555
.d C /
Dear Mr. Miller:
Reference:
NRC letter 9/30/81, J. R. Miller to G. Wuller, IP, subject:
Discrepancies in Thermal Analysis Clinton Power Station Unit 1 Docket No. 50-461 The attached information in response to the referenced letter, which we received on October 5, 1981, explains the discrepancy in the thermal discharge analyses and provides the basis for the numbers used in our calculations.
Please let us hear soon if you have any further questions on this matter.
Sincerely, l
G. E. Wuller Supervisor-Licensing l
Nuclear Station Engineering GEW/sc Enc.
cc:
H. H. Livermore, NRC Resident Inspector J. H. Williams, NRC Clinton Proj ect Manager John Lehr, NRC Environmental Engineering Branch J. H. Opelka, ANC syrl
!si !M*daa*f, POR J
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Response to " Request for Additional Information - Thermal Hydrology" 1.
The discrepancy in question has been traced to several factors.
The information presented in the text of the 1980 thermal demonstration (p. 3-1) is not what was actually used as input to the modeling that was conducted.
The information as incorrectly referenced in the text and that actually used in the modeling is as follows:
Text Used in Modeling Cire. Water Flow Rate 1267 cfs 1447 cfs (3-pump operation)
Heat Rejection 100%
6.4 x 10 Btu /hr.
5.9 x 10 Btu /hr.
9 92%
5.9 x 10 Btu /hr.
5.4 x 10 Btu /hr.
AT 100%
12.6 C
10.1 C
(Based on above heat and flows) 92%
11.6 C
9.3 C
Note:
92% values are calculated and were not directly referenced in the text.
Flow Rates The circulating water flow rate of 1267 cfs that was referenced in the text is the design basis minimum flow rate at a very high head, i.e., with a lake elevation of 677' MSL.
In conducting the modeling a flow rate of 1447 cfs was used.
The basis for this number (which was selected in 1978) was that it is the midpoint flow rate when considering the flow rate range calculated from the Williams and Hazen's equation for old pipe (C = 100) and new pipe (C - 140) conditions.
The j
. old pipe (worst case) calculation shows a flow rate of 1370 cfs at lake elevation 690' MSL.
The worst case value was not used in the modeling because other worst case assumptions were being included in other areas, e.g., 100% load factor and 1955 meteorology / hydrology in some cases.
Heat Rejection Rates l
The condenser heat rejection rate intended to be used was that for 100% load, i.e., 6.4 x 10 Btu /hr.
However, the heat 9
l rejection value used (5.9 x 10 Btu /hr.) was that listed in the original thermal demonstration as' that for " maximum expected operating conditions."
This " maximum expected operating condition" was 92% during the summer months and this was the basis of the oririnal thermal demonstration.
Thus, the 100% load cases shown in the 1980 thermal demonstration are, in I
fact, 92% and those listed as 92% are actually 85%.
l Temperature Reduction in Discharge Flume l
One additional area of discrepancy should be mentioned.
The statement on page 5-18 of the 1980 thermal demonstration report relative to the 0.5 C heat loss in the discharge flume is an average value.
The range for this is 0.2 C to 1.9 C.
The actual value for the 1955 case is abcat 0.5 C as indicated in the NRC staff's table, however, for the 1978 case the actual o
value is about 1.0 C.
. 2.
The total design service water flow rate is 44,000 gpm (98 cfs) and it will have a temperature rise conservatively estimated at 10 F.
Under normal operations about 95% (93 cfs) of this service water will go to the discharge flume, mix with condenser cooling water, and be discharged to the lake
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at the end of the flume.
Service water flow was not considered in the modeling done for the 1980 thermal demonstration although this flow would provide some reduction in the fiume temperature because of its lower temperature rise when compared to that of the circulating water system.
The combined circulating and service water temperature rise o
o for one unit operating at 100% powcr would be 20.1 F (11.2 C) 9 when using a heat rejection rate of 6.61 x 10 Btu /hr. (6.4 j
circulating and 0.21 service) and a cooling water flow l
rate of 1463 cfs (1370 circulating and 93 service).
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