ML20236A398

Safety Evaluation Re Potential Hazards Associated W/ Operation of & Potential Explosion Accidents at Rockwood Stone,Inc Quarry.Hazards Considered Insignificant,Based on Util Confirmatory Analysis & Independent NRC Evaluation

ML20236A398
Person / Time
Site:	Fermi
Issue date:	10/15/1987
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML20236A375	List: ML20236A371 ML20236A398
References
NUDOCS 8710220236
Download: ML20236A398 (3)

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• • • • • SAFETY EVALUATION BY THE OFFICE OF NRR RELATED TO THE OPERATION OF THE ROCKWOOD STONE INC. QUARRY DETROIT EDISON COMPANY (DECO)

Fermi-2 (Docket No. 50-341)

1. 0 INTRODUCTION By letter dated February 27, 1987, the NRC staff issued a Safety Evaluation Report (SER) regarding the potential hazards associated with the operation of, and the potential explosion accidents at, the Rockwood Stone, Inc. (RSI) quarry. In that SER the staff had determined that the operation of the RSI quarry was not expected to adversely affect the safe operation of the Fermi-2 plant. In particular the staff found that the postulated explosions of bulk quantities of the explosives stored at the quarry site did not pose a significant hazard to the safe operation of the plant. The staff believed that the associated ground motion and the peak hydrostatic pressures might also be insignificant. However, the staff required the licensee, DECO, to provide a confirmatory analysis of the postulated explosions to demonstarte that the ground motion and the hydrostatic pressure change hazards are insignificant with respect to the safe operation of the Fermi-2 plant. Be letter dated April 20, 1987, the licensee has submitted the confirmatory analysis requested in the SER. This safety evaluation describes the results of the staff's review of the licensee's submittal.

l 2.0 EVALUATION In the SER Dated February 27, 1987, the staff considered the potential ground l motion effects due to the detonation of the maximum stored explosives of 80000 '

pounds of ammonium nitrate fuel oil (ANF0) at the RSI quarry and due to the i detonation of a shipment of 40,000 pounds at the closest approach (two miles from Fermi-2). The staff compared the information pertaining to the RSI i quarry at Fermi-2 with similar data related to another nuclear power plant '

(where a quarry had used 82000 pounds of explosives) which had been previously reviewed and found safe. The findings for the other power plant were that the free field peak ground acceleration was less than 0.02g due to l the detonation of the explosives at a distance of 8700 feet. In view of the Fermi-2 seismic design values (i.e., SSE = 0.15g and OBE = 0.08g) and the distance (minimum of two miles) from the quarry to the plant, the staff expected that the potential ground motion at the Fermi-2 plant site was acceptably low. However, the staff felt that differences in subsurface geology between the Fermi-2 site and the previously analyzed site could affect ground motion and hydrostatic pressures. Therefore, the staff requested DECO to provide a confirmatory analysis of the postulated explosions and their effects on ground motion and peak hydrostatic pressures to demonstrate that the potential hazard was insignificant. The analysis was also to include a review of Fermi-2 construction activities and list any damages to structures due to the blasting that has occurred at the RSI quarry.

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-l 7 In its confirmatory analysis dated April 20, 1987, the licensee nas considered o the storage of explosives in the delivery trailers -at the quarry about 4 feet  !

above the ground surface level to be equivalent to a transit condition.

Therefor, the licensee has used the Regulatory Guide 1,91 (Ref 1) as the basis to evaluate the blast induced overpressure effects. The licensee has used the U.S. Navy Design Manual 7.2 Foundations and Earth Structures (Ref 2) to estimate the ground motion effects due to blasting.

The detailed calculations furnished with the licensee's letter of April 20, 1987, confirm that neither the blast-induced overpressure nor the ground motion effects pose a hazard to the Fermi-2 plant. The licensee estimated the peak hydrostatic pressures due to blasting by relating accelerations and '

displacement due to blasting with displacements due to the safe shutdown earthquake (SSE). The increase in the hydrostatic pressure due to blasting was then compared to the hydrostatic pressure due to the probable maximum flood at Fermi-2 and found to be insignificant.

With reference to the question of any damages to structures (on site or off site) due to the blasting at the RSI quarry, the licensee has furnished a private Consultant's report to show that the blasting activities at RSI quarry were not responsible for the residential damages that have been reported off site. The licensee has also reported that the construction activities at Fermi-2 extended from 1970 through 1984 whereas the RSI quarry has been in operation since 1982. No evidence of structural damage due to blasting activities at the RSI Quarry to any safety-related structures at Fermi-2 site was noticed during an examination of these structures conducted after the Perry, Ohio, earthquake of January 31, 1986.

The staff performed an independent evaluations of the blast generated displacements, velocities, and accelerations of the ground using the empirical relationships given in Hendron's paper, " Engineering of Rock Blasting on Civil Projects" (Ref 3). This evaluation also indicated that the ground motions due to the blasting activities at the RSI quarry have no adverse effects on the safety of the Fermi-2 power plant structures. This evaluation was made assuming the shortest distance from the RSI quarry to the safety-related structures is about two miles. However, the licensee does not own the land between the quarry and the plant boundary, and has no control over the quarry operation. Therefore, the licenses should reevaluate the safety of the plant and inform the NRC if and when the distance from the quarry to the safety-related structures becomes shorter than two miles. Our preliminary evaluation indicated that there will be no safety hazard even if the distance from the quarry becomes one mile.

3.0 CONCLUSION

S The staff has reviewed the licensee's confirmatory analysis of the effects of postulated explosions in connection with the operation of the RSI quarry in )

the vicinity of the Fermi-2 plant. Based on this analysis and on the independent evaluation by the NRC staff the staff is satisfied that the hazards due to blast-induced overpressure, ground motion and hydrostatic pressure changes are insignificant with respect to the Fermi-2 nuclear plant. i The licensee should, however, reevaluate the safety of the plant if the distance from the RSI quarry to the safety-related structures at the plant becomes less than two miles.

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4.0 REFERENCES

1. U.S. Nuclear Regulatory Commission Regulatory Guide No.1.91. ,

2. U.S. Navy Design Manual No. 7.2, Foundations and Earth Structures, 1982.

3. Hendron, A.J. " Engineering of Rock Blasting on Civil Projects."

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