ML18347A625
| ML18347A625 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 11/21/1975 |
| From: | Bixel D Consumers Power Co |
| To: | James Keppler NRC/RGN-III |
| References | |
| Download: ML18347A625 (3) | |
Text
Mr James G. Keppler Office of Inspection Region III US Nuclear Regulatory 799 Roosevelt Road Glen Ellyn, IL 60137 Commission DOCKET 50-255, LICENSE DPR-20 PALISADES PLANT, THERMAL DISCHARGE
./
On October 24, 1975 the temperature differential between the intake and dis-charge exceeded 5°F for a period of about one hour.
The maximum differential temperature reached 6.3°F during this period of time.
An analysis of this event showed that after subtracting the effect of the service water (which is ex~mpt from the temperature limits) the actual discharge temperature would have been less than 5°F and, therefore, no Technical Specification limit was exceeded.
This method of analysis (with respect to the 5°F Technical Speci-fication limit) was discussed in our letter to Dr George W. Knighton dated July 11, 1975 and was also discussed with members of your staff dl.l.r>ing a meeting held on September 17, 1975.
The attached is a description of the analysis used to show the effect of the service water and is provided for *your information.
David A. Bixel Assistant Nuclear Licensing Administrator CC:
Director of Nuclear Reactor Regulation File
- 13382
/
PALISADES.PL.ANT
.. EXAMPLE CALCULATION EFFLUENT DISCHARGE T~ERATURE The total heat rejected to the lake is:
Where:
~ = [mcp~T
= (ll\\i + ~D + ~)Cp(T:MB-TI) m = Mass Flow Lb/h T = Temperature, °F W = Wier BD = Blowdown Pipe D = Dilution Water
- MB = Mixing Basin Discharge I = Inlet Cp = Specific Heat of Water =
1 Btu lb x °F (1)
The maximum allowable heat rejected to the lake permitted by the 5°F limit on the closed cycle cooling system is:
Qccs ~ (ll\\i + ~D + ~)Cp(50F)
The heat rejected to the lake from the closed cycle cooling system (adjust-ing the total by subtracting the heat of the service water system, which is exempt from this requirement) is:
~- m x Cp x ~T SW SW or Solving for (T:MB - TI) gives:
/
TMB -
TI =
Q
+ M x Cp x ~T CCS SW SW (1\\, = ~D = ~)Cp
To determine the maximum permissible total discharge temperature which will meet the 5,°F limit for the closed cycle cooling system substitute Q (in the limit) equal to (rilw + ~D + mD)Cp(5°F) or:
ccs (rilw + ~D + ~)Cp(5°F) + msw x Cp x ~Tsw (11\\i + ~D + ~)Cp On October 24, 1975, a discharge temperature of 6.3°F was observed.
The following data was measured*~ conservatively estimated for use in deter-mining heat rejected to the lake.
TMB TL = 6.3°F 11\\i
= '5;;400 gpm = 2.70 x 106 Lb/h
~D
= 1,800 gpm = 9.oo x 105 Lb/h
~
= 60,000 gpm = 2.998 x 107 Lb/h m
= 10,000 gpm = 5.0 x 106 Lb/h SW
~T
= 10°F SW From equation (1) the total heat rejected to the lake is:
8 QT = 2.12 x 10 Btu/h (42% of Limit)
From equation (2), the maximum permissible total discharge temperature is:
= 5°F + 5.0 x 106.Lb/h x 10°F 3.36 x 107 Lb/h
= 5°F + L49°F (2)
November *21, 1975