ML18046A427
| ML18046A427 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 02/20/1981 |
| From: | Hoffman D CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | Crutchfield D Office of Nuclear Reactor Regulation |
| References | |
| REF-GTECI-A-02, REF-GTECI-RV, TASK-A-02, TASK-A-2, TASK-OR NUDOCS 8102250057 | |
| Download: ML18046A427 (5) | |
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General Offices: 212 West Michigan Avenue, Jackson, Michigan 49201 * (517) 788-0550
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!~.rt February 20, 1981 Director, Nuclear Reactor Regulation Att Mr Dennis M Crutchfield, Chief Operating Reactors Branch No 5 US Nuclear Regulatory Commission Washington, DC 20555 DOCKET 50-255 - LICENSE DPR PALISADES PLANT - ASYMMETRIC LOCA LOADS Consumers Power Company letter dated August 29, 1980 informed you of our active participation in the CE Owners Group (GEOG) for resolution of the effects of Asymmetric LOCA Loads for the Palisades Plant.
As stated in that letter, several plant specific analyses were required to obtain the correct loads on the cavity shield wall.
These analyses were not completed when the generic plant GEOG was submitted on July 1, 1980.
A structural analysis for the Palisades reactor vessel cavity walls was completed by Bechtel in November 1980.
This analysis was performed using loads calculated by Combustion Engineering (CE) and Ebasco for a full two-area cold leg break assuming minimal cavity vent areas.
The resultant loads in the cavity wall structure exceeded FSAR code allowable limits.
Ebasco is currently reanalyzing the reactor cavity pressurization and CE is reanalyzing the reactor vessel and intact reactor coolant pump loads.
Credit is being taken for the actual geometry at Palisades (see attached Figures l and 2).
The small gap between the cold leg and the removable bricks, located in the pipe passageway through the biological shield wall, limits the break area to -1000 inches 2
- After the pipe impacts on the bricks, it rebounds and sufficient pressure is generated at the location of the break to push the movable bricks and the liner out of the pipe passage.
This will allow the broken cold leg to move to a full two-area break.
Conservative assumptions are being made for the brick blowout times for the pipe break area opening calculations and for the reactor cavity pressurization calculations.
The attached schedule shows the analyses being performed and their expected completion dates.
Preliminary calculations have been performed by Bechtel,
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based upon Ebasco's reactor cavities pressurization analysis for a 1000-inch 2/fo break which indicates that the current analysis will likely yield acceptable
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results.
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Director, Nuclear Reactor Regulation Palisades Plant February 20, 1981 If the-results of the Bechtel structural cavity wall analysis show that unac-ceptable loads exist, one of the following actions may be taken by Consumers Power Company:
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CE may be requested to reperform the reactor vessel and intact loop reactor coolant pump loads analysis using nonlinear softened support load deflection curves provided by Bechtel.
Bechtel would then perform another Palisades reactor cavity evaluation.
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Consumers Power may request Bechtel to complete a plant modification con-ceptional design that would limit the cold leg break area.
The decision will be based on many conditions which are now still variables.
We will inform you of our decision as to what course of action we intend to follow.
David P Hoffman Nuclear Licensing Administrator
. CC Director, Region III, USNRC NRG Resident Inspector-Palisades Attachments C3l
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FIGURE 1 - PALISADES PRIMARY COOLANT SYSTEM PIPING (DRAWING M-3)
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PALISADES ASYMMETRIC LOADS ANALYSIS SCHEDULE EBASCO MINIMUM BLdW,..OUT TIME 1/15 COMBUSTION DEFINE AREA DEVELOPMENT CURVE 1/19 COMBUSTION TWO-STEP MASS ENERGY RELEASE 2/13 EBASCO CAVITY PRESSUREI~
ZATION ANALYSIS 2127 I
BECHTEL RC STRUCTURAL ANALYSIS 4/17 '
EBASCO SEND PRESSURE*
DAT A TO_ COMBUSTION CASES:
- 1) 1000 IN2 BRK WITH VENTING-BRICKS.
BLOWING OUT 2).1000 IN2 BRK-BRICKS RESTRAINED 1/22 COMBUSTION RV & INT ACT LOOP Rep-LOADS ANALYSIS (LINEAR ELASTICS SUPPORTS & REDUCED PRESSURE) 2/20