ML19248D363
| ML19248D363 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 07/06/1979 |
| From: | Jay Collins NRC - TMI-2 OPERATIONS/SUPPORT TASK FORCE |
| To: | Rusche B GENERAL PUBLIC UTILITIES CORP. |
| References | |
| NUDOCS 7908150668 | |
| Download: ML19248D363 (1) | |
Text
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UNITED STATES
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NUCLEAR REGULATORY COMMISSION 2
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s 1R h l#D 6 July 6, 1979
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? ~.' ' 4 c c 's MEMORM.'DUM FOR:
Ben C. Rusche, GPU FROM:
John T. Collins, Deputy Director, TMI-2 Support
SUBJECT:
GROUNDWATER MONITORING AT TMI-2 Reference is made to the attached memo from L. G. Hulman, Chief, Hydrology-Meteorology Branch, NRR, to R. H. Vollmer, dated June 26, 1979, subj ect as above. We request that you review the enclosed monitoring program criteria at TMI and provide me with an assessment indicating how you intend to imple-ment these criteria and the proposed schedule for implementation.
If you believe all or part of the program is not necessary you should provide technical justification to support this position. We would appreciate your response to this memo by July 13, 1979.
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Li JJohn T. Collins, Deputy Director TMI-2 Support
Enclosure:
As Stated cc:
R. Arnold, GPU p( Vollmer L. Hulman 7 90815 cGG8 op
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UNITED STATES y
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JUN 2 61979 Docket No. 50-320 MEMORANDUM FOR: Richard H. Vollmer, Assistant Director for Systems & Projects, DDR
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William E. Kreger, Assistant 0.ir or d19f
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for Site Analysis, DSE FROM:
L. G. Hulman, Chief Hydrology-Meteorology Branch, DSE
SUBJECT:
GROUNDWATER MONITORING AT THREE MILE ISLAND, UNIT 2, DOCKET NO. 50-320 During my site visit to the subject plant on June 6, I discussed the water-tightness of the Unit 2 containment and auxiliary btildings with you and J. Collins. Upon consideration of my understaading of the design of the structures and the r, umber of penetrations through the structure below grade, I recommend that the groundwater in the vicinity of the structures be closely monitored to assure that highly contaminated water is not leaking from the structures.
If such a condition is detected early by monitoring, mitigating action should be taken. Techniques of mitigation should be considered and contingency plans n. de as part of the implementation of this program. The enclosed criteria for such monitoring system is recomended.
Because of the character of the island subsurface materials, any leakage would most likely flow fairly rapidly toward the Susquehanna River (ir. as
.little as 14 days). There appears to be no possibility of regional acuifer contamination.
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. G. Hulman, enief Hydrology-Meteorology Branch Division of Site Safety and Environmental Analysis
Enclosure:
Recomended g w.
monitoring criteria cc: See next page
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n JUN 2 61979 Richard H. Vollmer.
cc: w/ enclosure H. Denton D. Muller R. Mattson R. DeYoung /
D. Eisenhut J. Collin /
R. Bangart W. Houston W. Bivins PDR T. Murphy r
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MONITORING PROGRAM CRITERIA 0 TMI The objective of the proposed seepage monitoring. program is to assure that no contaminated surface or groundwater migrates
- toward the. property boundary.
undetected. The system should be designed to provide early warning of leak-age, and to allow prompt and effective mitigation.
The gradient of the groundwater slopes away from approximately the center of the island and groundwater can move in several directions. Therefore, a ring of monitoring wells should be established around the containment and auxiliary buildings. The wells should be spaced about 200 feet apart and extend through the island sands and gravels to the shale surface. The wells should be placed as close to the buildings as is practicable. Well screens should.be. designed to alluw water. collection at all levels above the shale-sand surface. Pump-ing equipmeni. and. storage facilities should be on hand to. pump the contaminated water out if contamination occurs. Due to the potential rapid rate of ground-water movement, the wells should be monitored once every day or two by pumping and testing water samples for activity. This monitoring frequency should be sufficient.to detect activity in time to initiate mitigation measures. Mitigation measure planning should also be initiated.
The wells should be constructed to monitor groundwater above elevation 270 ft msl and shuld be large enough to handle a submergible pump. Electric power will be necessary to the pumps.
Installation of the wells should be carefully undertaken because of the large number of underground conduits.
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