ML13304B519
| ML13304B519 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 02/26/1979 |
| From: | Baskin K Southern California Edison Co |
| To: | Moore V Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML13304B520 | List: |
| References | |
| NUDOCS 7903140381 | |
| Download: ML13304B519 (7) | |
Text
REGULATORY FORMATION DISTRIBUTION SY*M (RIDS)
ACCESSION NBR:7903140381 DOC.DATE: 79/O/26 NOTARIZED: NO DOCKET4#
FACIL:50-361 SAN ONOFRE NUCLEAR STATION, UNIT 2, SOUTHERN CALIFORN 050 6
50-362 SAN ONOFRE NUCLEAR STATION, UNIT 3, SOUTHERN CALIFORN 0500 62 AUTH.NAME AUTHOR AFFILIATION BASKINK.P.
SOUTHERN CALIFORNIA EDISON CO.
RECIP.NAME RECIPIENT AFFILIATION MOORErV.A.
ASSISTA T DIRECTOR FOR E V RONMENTAL PROJECTS
SUBJECT:
FORWARDS REPTS ON AT TREATMENT VECO 'MENDATIONSPROTOTYPE STUDY FOR HEAT TREATMENT & EFFECTS OF UNITS ON MARINE ENVIRONAS REQUIRED BY GOVT OF CA AS CONDITION F-R THERMAL EXCEPTION FOR ELkVATED DISCHARGE TaMPS.
c DISTRIBUTION CODE: ZZZZB CO fIES RECEI VED:LTR.
N EN L SIZE:
4 TITLE:
- S P E C I A L D I S T R I B U T I NOTES:
RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL L(J*
TOTAL NUMBER OF COPIES REQUIRED: LTTR 0 ENCL 0
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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 MEMORANDUM FOR:
TERA Corp.
FROM:
US NRC/TIDC/Distribution Services Branch
SUBJECT:
Special Document Handling Requirements Please use the following special distribution list for the attached document.
L PDR LPOZ' O L JC~
- 2. The attached document requires the following special considerations:
M Do not send oversize enclosure to the NRC PDR.
Only one oversize enclosure was received -
please return for Regulatory File storage.
Proprietary information -
send affidavit only to the NRC PDR 8ther: (specify) cc: DSB Files TIDC/DSB Authorized Signarure
Southern California Edison Company P. 0. BOX 800 2244 WALNUT GROVE AVENUE ROSEMEAD, CALIFORNIA 91770 K. P. BASKIN TELEPHONE
- MANAGER, GENERATION ENGINEERING 213-572-1401 February 26.
1979 Director, Office of Nuclear Reactor Regulation Attn: V. A. Moore Asst. Director Environmental Projects Division of Site Safety and Environmental Analysis U.S. Nuclear Regulatory Commission Washington, D.C.
20555 Gentlemen:
Subject:
Docket Nos. 50-361 and 50-362 San Onofre Nuclear Generating Station Units 2 and 3 This letter is for the purpose of submitting for your infor mation the final report on studies required by the California State Water Resources Control Board as a condition to the Thermal Exception granted to allow the use of elevated dis charge temperatures (heat treatment) for the control of fouling organisms in the circulating water system.
The submittal contains six copies of the following enclosed reports:. Heat Treatment Recommendation for San Onofre Nuclear Generating Station, Units 2&3.. San Onofre Nuclear Generating Station.
Units 2 and 3 Prototype Study for Heat Treatment Procedures, Final Report, December, 1978.. Spatial and Temporal Pattern of Temperature, Nutrients, Seston, Chlorophyll-A and Plankton Off San Onofre from August, 1976-September, 1978, and the relationships of these patterns to the SONGS Cooling System and Preliminary Reoort of Patterns of Abundance of Ichthyoplankton Of San Onofre and Their Relationship to the Cooling Operations of SONGS; (Marine Review Committee, California Coastal Commission) January 31, 1979.
The studies were aimed at optimization of the heat treatment technique.
The result is a proposed screenwell and intake heat treatment scheme that is at a lower temperature than was our comm ' Fe
, 1 r
a similar duration.
The 7 9 0T3FILE COPY 790314038
-2 frequency for heat treatment of the intake conduit is generally reduced while the discharge conduit will not need heat treat ment under most conditions.
The specifics of our proposed heat treatment scheme are presented in Enclosure 1.
The Marine Review Committee report on plankton is taken from on-going work for the Coastal Commission and provides information pertinent to normal operation as well as heat treatment.
Southern California Edison Company has requested that the State Board approve this work as a successful demonstration in accordance with section 316 (a) of the Federal Water Pollution Control Act, and remove all conditions from the Thermal Excep tion granted.
State Board approval of the proposed method of determining the frequency, degree, and duration of heat treatment was also requested.
Sincerely, cc:
Collette Gilson, MRC
ENCLOSURE 1 HEAT TREATMENT RECOMMENDATION FOR SAN ONOFRE NUCLEAR GENERATING STATION, UNITS 2&3 I. General Conditions A. The frequency of heat treatment will be determined, in part, by a growth model for the Bay Mussel, Mytilus edulis, as described in Figure 1. Measurements and observations of biological material from the conduit, an'd observation of cooling water system parameters will also be used.
System operational constraints may require that a heat treatment be conducted prior to the time scheduled using the parameters above, typically during the prior weekend.
B. Heat treatment temperature and duration will be based on the Time-Temperature Mortality Curve for the Bay Mussel, Mytilus edulis (Figure 2), which includes an additional amount of time added to account for tempera ture measurement inaccuracy, non-homogeneity of temper ature in the cooling water system, and other unknown factors.
The highest temperature consistent with plant operating requirements will be selected to keep the heat treatment time to a minimum. Target times will be rounded up to the nearest five minutes.
C. The target temperature and time is subject to th.e precision which can be practicably attained by station operators.
Consequently, during the temperature rise period, before initiating heat treatment, and as the influent temperature varies, temperatures may be inadvertently increased above the target temperature due to equipment limitations; however, the target temperature is not expected to be exceeded by more than 50F or more than ten minutes.
If temperature sensor readings differ slightly, the target temperature will be reached using the sensor with the lowest reading.
D. One or more heat treatments of the intake and discharge conduits will be conducted early in the initial operation of each of the units, as part of the startup testing of all plant equipment and systems.
Heat treatment operations will be flexible with respect to temperature, duration and frequency for this period and for at least the first year of commercial operation, in order to adjust to the specific operational and biofouling conditions of Units 2&3.
-2 Specific Conditions A. Intake Conduit and Screenwell
- 1. Heat treatment of the intake conduit, fish return system and screenwell will be performed at 100 0F (as measured in the screenwell) for 2.1 hours1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />.
100 F represents the presently expected, maximum temperature capability of each unit.
The heat treatment temperature will be adjusted upward or downward to the highest temperature compatible with station operation during initial operation of the units.
A corresponding change will be made to the heat treatment duration in accordance with the Bay Mussel Time-Temperature Mortality Curve (Figure 2).
(Heat treatment duration represents the period of time at the target te perature, and not the time required to reach 100 F and the time to return to normal operation).
- 2. Heat treatment of the intake conduit, fish return system and screenwell will be conducted at intervals predicted by a growth model, which is based on ambient water temperature. Heat treatments will be scheduled using the San Onofre Units 2&3 heat treatment Decision Flow Chart (Figure 1).
Heat treatments will also be conducted prior to or following a station outage, if the outage period is anticipated to extend-beyond the time of the next (growth model) predicted heat treatment.
B. Discharge Conduit
- 1. As long a8 normal operating discharge tempesatures exceed 80 F for a minimum of 1000 hours0.0116 days <br />0.278 hours <br />0.00165 weeks <br />3.805e-4 months <br />, 85 F for 150 hours0.00174 days <br />0.0417 hours <br />2.480159e-4 weeks <br />5.7075e-5 months <br /> or 900F for 31 hours3.587963e-4 days <br />0.00861 hours <br />5.125661e-5 weeks <br />1.17955e-5 months <br />, the discharge conduit will not require heat treatment.
Unless these conditions are met, it must be assumed that settling and growth of biofouling organisms has occurred. When these conditions are not met, growth calculations, based on ambient intake water temperatures, will be used to schedule a discharge conduit heat treatment.
- 2. When required, the discharge conduit for Unit 2 wil; be heat treated at a discharge emperature of 105 F for 1.1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> and Unit 3 at 105 F for 0.9 hour1.041667e-4 days <br />0.0025 hours <br />1.488095e-5 weeks <br />3.4245e-6 months <br />.
These times are the onshore heat treatment times required to treat the furthest point offshore for 0.58 hours6.712963e-4 days <br />0.0161 hours <br />9.589947e-5 weeks <br />2.2069e-5 months <br />, the time indicated by the Time Temperature Mortality Curve for the Bay Mussel (Figure 2).
The differences compensate for conduit lengths which become significant because of different discharge velocities between heat treatment and normal operation.
RVR:lyn 2BRVR20.8