ML20238B235
| ML20238B235 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 05/14/1975 |
| From: | Sniezek J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| To: | Madsen G NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| Shared Package | |
| ML20238B208 | List:
|
| References | |
| FOIA-87-428 NUDOCS 8709010129 | |
| Download: ML20238B235 (2) | |
Text
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p-0 UNITED STATES NUCLEAR REGULATORY COMMISSION.
W ASHINGTON, D. C. 20555 MAY 1 4 N S l
G. L. Madsen, Chief, Reactor Construction
& Operations Branch, IE:IV REQUEST FOR INTERPRETATION / CLARIFICATION RELATIVE TO BLASTING (F40030H1)
This memorandum is in response to your request for guidance relative to excavation activities for safety related structures, especially with respect to blasting at the Comanche Peak facilities (Docket Nos. 50-445 and -446).
Generally, excavation (earth removal) is not' considered to be a safety related activity; however, certain aspects or activities related to excavation such as ground water I
control, blasting, and subsurface preparation, may be safety related.
In regard to blasting, it is not the blasting of material to be excavated that is of major concern but the effect of blasting on adjacent structures--rock structures in this l
case.
If it were certain that blasting would not affect
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anything except the material to be removed, blasting would i
not be considered to have safety significance. However, even with overbreak protection / precautions, the potential exists for structural damage to rock not intended to be damaged by blasting.
Because of the magnitude and intensity I
of energy application during blasting, widespread shattering l
of rock.could occur.
Blasting could also affect adversely the underlying or adjacent rock by fissuring.
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Due to the potential damage to adjacent rock structures l
by blasting, we agree with you that certain aspects of excavation are safety related, and that the control and monitoring of blasting are in this category. Thus, some l
excavation activities for safety related structures require that pertinent requirements of Appendix B to 10 CFR 50 apply. We have consulted with NRR on this matter and they concur in our position.
8709010129 870827 l
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G. L. Madsen MAY 1 4 575
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Apparently the licensee was aware of the safety significance of this activity since a-50.55(e) report was issued when an overcharge in blasting caused rock fractures to extend beyond the excavation perimeter.
If you have any further questions regarding this matter,
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please contact R. A. Rohrbacher or me.
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. H. Sniezek, Chief acility Inspection Branch 0ffice of Inspection
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