ML18078A694

Fuel Grid Impact Loads for Salem Unit No 2. Supplements NS-TMA-1996 & Provides Maximum Fuel Grid Impact Loads from Seismic & Blowdown Forces

ML18078A694
Person / Time
Site:	Salem
Issue date:	01/12/1979
From:	WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP.
To:
Shared Package
ML18078A693	List: ML18078A692 ML18078A694
References
NUDOCS 7901230264
Download: ML18078A694 (3)

Text

WESTINGHnusE NON-PROPRIETARY e

Attachment B Fuel Grid Jmoact Loads for Salem Cnit No. 2 The information presented below supplements the contents of Section 3.5 of Referen~e (a) and provides revised maximum fuel grid imps.ct loads from seismic and blowdown forces. A* summary of the fuel grid. impact loads is provided in Table A-1. The rationale employed in developing the revised impact loads is as follows:*

1. The 95 x 95 grid crush strength test value at operating temperature has increased from. [ f pounds, which was used in Reference (a) to [

• Jc pounds. This improved grid strength is justified by the results of additional grid impact tests.

2. The previously r-eported loss-of-coolant . grid impact load of [. Jc pounds was for a double ended break opening area at the pump outlet nozzle.

This break location is no longer considered in the evaluation for grid.impact loads; the rigidity of the primary equipment supports li:nits the actual break opening area to a very low; value and the resulting' grid im[;Jact loads are low in magnitude. This conclusion was drawn from calcuhtions for break opening area using the transient broken pi9e end displacements with applied blowdown forces for a double ended pump outlet nozzle rupture. The calculations v1ere performed for many Westinghouse plants. In no case did the maximum area exceed .40 square inches. Parametric studies for fuel grid impact loads re'.'ealed that using a reduced break opening area for the pump outl2t nozzle produced low grid impact loads. Therefore, the pump outlet nozzle break location can be eliminated from consideration and the vessel inlet nozzle break location becomes the limiting.break location for grid impact loads. Toe peak grid impact load for the vessel inlet nozzle break was I f pounds.

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3. As shown in Figure 3-4 of Reference (a), the actual tr:rnsicnt brcuk opening

• area for a vessel inlet nozzle brenk hns an average value of 55 square inches.

The break opening- area used to calculate the applied blowdown 101:1ds was 100 square inches. Parametric studies on grid imp.'.l.ct loads for a break Rt the vessel inlet nozzle have shown that- the grid impact loads would ')e reduced 30% by .. the effect of this reduced break area. Therefore, the grid im~act loads for the worst case break location are approximately 70% of r .f pounds or r. :j pounds.

4. The seismic grid impact load varies with the elevation of the grid. The peak inlet nozzle break impact loads occur at the grid which has a peak seismic impact load of [ ~cpounds. The pump outlet break grid impact peak load occurs at the grid which has a seismic peak load of [ Jc pounds .

TABLE A-1 Summnrv of Revised Fuel Grid Tmonct Londs Irri.pact Loads Comments

.c 95 x 95 Limit Used in Report 95 x 95 Limit Including Recent Test Results Impact Loads for Double Ended Pump Outlet Nozzle Impact Loads for Reduced Area Pump Outlet Nozzle Breaks are Small 2

100 in RPV Inlet Nozzle Grid Load 2

55 in RPV Inlet. Nozzle Grid Load

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Seismic Impact Peak Load at Grid for \Vhich Pump Outlet Nozzle Break Peak Load Occurs Seismic Impact Peak Load at Grid for \Vhich RPV Inlet Nozzle Break Peak Load Occurs.

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