ML19350E348
| ML19350E348 | |
| Person / Time | |
|---|---|
| Site: | Duane Arnold  |
| Issue date: | 06/08/1981 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML19350E347 | List: |
| References | |
| NUDOCS 8106170354 | |
| Download: ML19350E348 (2) | |
Text
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UNITED STATES
..Og "
' 'g NUCLEAR REGULATORY COMMISSION E
.. p WASHINGTON, D. C. 20555
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO. 70 TO LICENSE NO. DPR-49 IOWA ELECTRIC LIGHT AND POWER COMPANY CENTRAL IOWA POWER COOPERATIVE CORN BELT POWER COOPERATIVE DOCKET NO. 50-331 DUANE ARNOLD ENERGY CENTER Introduction The Duane Arnold Energy Center (DAEC) river water supply system consists of two river water supply pumps, each of 6000 gpm capacity, in each of two loops. This system supplies river water for the residual-heat removal service water system (RHRSWS) and emergency service water system (ESWS) via the wet-pit sump of the RHRSW & ESW systems.
The RHRSWS supplies cooling water for heat removal from the Residual Heat Removal (RHR) heat exchangers and a source of water if post accident flooding of the core or primary containment is needed. The ESWS provides a supply of cooling water to essential safeguards equipment. Two one-half size RHR ervice water pumps supply each of the two RHRSWS trains, and one full size ESW pump supplies each of the two ESWS trains.
One ESW pump (rated at 1200 gpm) and two RHRSW pumps'(cach rated at 2400 gpm) are required to supply to at least one train of the ESWS and RHRSW systems (respectively) in event of either a design basis accident or loss of offsite AC power. The combined total flow requirements of the RHRSWS and ESWS is thus 6000 gpm. This flow must be provided by the river water supply system to the RHRSWS and ESWS wet-pit sump.
This minimum flow requirement can be satisfied by one of ~the four service water supply pumps, which are cach rated at 6000 qpm.
Evaluation Minimum river level at DAEC is 724' 9".
The maximum elevation to which the water must be pumped is 769' 8", for a minimum Total Dynamic Head (TDH) requirement of slightly less than 45 feet.
From this point, the water flows downhill about 18' 8" through pipes to the discharge level in the l
ESWS and RHRSWS wet-pit sump at slevation 751' 0".
Total system discharge losses from the river water supply pump discharge to the discharge into the wet-pit sump have been measured to be no more than 18 feet at i
6000 gpm. Total system losses from the river water supply pump discharge to the pit discharge are therefore less than the head available due to the elevation difference between these two points. Consequently, the TDH 8106170 3hh
- required to deliver the required flow to the wet-pit sump is slightly less than 45 feet.
The licensee has proposed changing the DAEC Technical Specifications to modify the surveillance requirements pertaining to the river water supply system to 1) increase the frequency of routine flow rate tests,
- 2) add additional flow rate tests when river elevation drops below a certain predesignated level, and 3)' provide for daily denonstrations of operating pump flow rates. In addition, the licensee has proposed changing the requirement for a demonstration of pump manufacturer's nameplate data of a pump TDH of 57 feet to a demonstration of pump TDH of 46 feet, to more clearly reflect the requirements of the system.
We have reviewed the proposed revisions to the Technical Specifications and find them acceptable. Based on our review of the information provided by the licensee, we have concluded that the Technical Specification requirement to demonstrate a river water supply pump TDH of 57 feet is based only on manufacturer's nameplate data and does not represent system requirements. We have also concluded that the TDH requirement proposed by the licensee is adequate to meet these requirements and that the increased surveillance requ1rements proposed provide additional assurance that adequate river water supply for the ESWS and RHRSWS is available.
Environmental Considerations We have determined that the amendment does not involve a change in effluent types or total amounts nor an increase in power level and will not result in any significant environmental impact. Having made this determination, we have further concluded that the amendment involves an action which is insignificant from the standpoint of environmental impact and pursuant to 10 CFR Section 5.1.5(d)(4) that an environmental impact statement or negative declaration and environmental impact appraisal need not be prepared in connection with the issuance of the amendment.
Conclusions We have concluded, based on the considerations discussed above, that:
(1) because the amendment does not involve a significant increase in the probability or consequences of accidents previously considered and does not involve a significant decrease in a safety margin, the amendment does not involve a significant hazards consideration, (2) there is reasonable assurance that the health and. safety of the public will not be ndangered by operation in the proposed manner, and (3) such activities will be conducted in compliance with the Commission's regulations and the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.
Dated: June 8,1981 e