ML19260D092
| ML19260D092 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 01/16/1980 |
| From: | Ross D Office of Nuclear Reactor Regulation |
| To: | Bacon C AFFILIATION NOT ASSIGNED |
| Shared Package | |
| ML19260D093 | List: |
| References | |
| NUDOCS 8002070397 | |
| Download: ML19260D092 (2) | |
Text
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}. b JAN 161900 Mr. Conrad G. Bacon 2960 Hannah Avenue Norristown, Pennsylvania 19401
Dear Mr. Bacon:
Your recent letter to Mr. Harold Denton regarding the Limerick Generating Station, Units 1 and 2 has been referred to me for reply.
In your letter, you questioned the necessity for the Nuclear Regulatory Commission's (NRC) current review of the effects of blasting in the Pottstown Trap Rock Quarry on the Limerick Generating Station (Limerick f acility).
In response to your inquiry, the events which lead to this investigation and the current status of the inves-tigation are presented below.
As your letter points out, the matter began with a letter from Mr. Frank Romano.
His letter dated April 12, 1979, questioned whether the structural design and foundation of the Limerick f acility could accommodate the ground motion that results from blasting in the Pottstown Trap Rock Quarry.
The quarry is adjacent to the site boundary and the reactor buildings are about 3600 feet from the current point of closest blasting. Mr. Romano's letter was treated as a request for action under Section 2.206 of 10 CFR of the NRC's regulations, even though Mr. Romano's letter did not cite this regulation.
The geology of the Limerick site was investigated as part of the Ato'mic Energy Connission's (NRC's predecessor) review of Philadelphia Electric Company's construction permit application for the Limerick facility. The geology and seismology portion of this review briefly considered blasting at the quarry but concentrated on defining a postulated earthquake to serve as the design basis for safety structures, systems and components at the Limerick facility. A Safety Evaluation Report was issued in November 1971 and recommended issuance of a construction pennit. Later, during excavation for the foundation of the reactor buildings, faults were discovered. A geologic investigation was per-formed and was concluded in late 1974. This investigation concluded that differential movement along the fault zones had ceased 150 to 200 million years ago.
It is important to note that operation of the quarry had been underway for about 40 years when the geologic investigation was conducted.
While these pieces of information are important, they are not sufficient to com-pletely answer the question raised by Mr. Romano in light of our current require-ments for the seismic design of nuclear power plant structures.
The additional conclusions that NRC needs to reach in order to be be sure that the blasting will not adversely affect the Limerick facility are that (1) the effect of blasting is less severe than the earthquake that is postulated as the basis for the design of the safety structures, systems, and components and (2) blasting will not cause new differential movement along the faults under the reactor buildings' foundations.
1937 250 M7 80090"O M M
JAN 1 c 1330 Mr. Conrad G. Bacon To reach these conclusions we have to obtain (1) additional information on the blasting methods used in the Pottstovo Trap Rock Quarry and (2) measurements of shock waves from the blasting. Some of this information was obtained from the operators of the quarry and Philadelphia Electric Company in meetings held on December 18, 1979.
In addition, Philadelphia Electric Company is to submit additional information to the NRC by January 15, 1980.
When the NRC and our consultant, the U. S. Geological Survey complete the review of the information, a report will be issued sunmarizing our findings.
The investigation we are currently conducting would have normally been performed as a portion of our operating license review of the Limerick plant. Therefore, it does not represent an increase in the overall effort by the NRC staff or by Philadelphia Electric Company, but only a change in the normal schedule for per-forming a portion of the review.
We appreciate your concern and interest in the Limerick facility and we trust that this information is responsive to your concerns.
Sincerely, D. F. Ross, Jr., Acting Director Division of Project Management Office of Nuclear Reactor Regulation 1937 251
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