ML20027D312
| ML20027D312 | |
| Person / Time | |
|---|---|
| Site: | Midland |
| Issue date: | 11/03/1982 |
| From: | Wilcove M NRC OFFICE OF THE EXECUTIVE LEGAL DIRECTOR (OELD) |
| To: | STAMIRIS, B. |
| References | |
| ISSUANCES-OL, ISSUANCES-OM, NUDOCS 8211040106 | |
| Download: ML20027D312 (11) | |
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11/03/82 UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION
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BEFORE THE ATOMIC AND SAFETY LICENSING BOARD l
In the Matter of
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CONSUMERS POWER COMPANY
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(Midland Plant, Units 1 and 2
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HRC STAFF PARTIAL RESPONSE TO j
INTERVENOR BARBARA STAMIRIS' INTERR0GATORIES AND DOCUMENT REQUEST TO THE STAFF, DATED AUGUST 30, 1982 l
I.
INTRODUCTION i
i On August 30, 1982, Intervenor Barbara Stamiris filed "Stamiris Interrogatories and Document Requests to Nuclear Regulatory Commission."
i Pursuant to 10 C.F.R. E 2.720(h)(2)(ii), written interrogatories to be answered by the Staff are to be filed with the presiding officer.
Upon making the necessary findings under that provision, the presiding officer i
may then require the Staff to answer the interrogatories. Ms. Stamiris i
i did nct comply with the prcvisions of 10 C.F.R. s 2.720(h)(2)(ii).
- However, in the spirit of cooperation between the parties and to expedite the completion of discovery in this proceeding, but without waiving the provisions of 10 C.F.R. s 2.720(h)(2)(ii) with respect to any other interrogatories, the Staff voluntarily provides this partial response to Ms. Stamiris' interrogatories.
Responses to other interrogatories contained in Ms. Stamiris' August 30, 1982 sub:nittal will be forthcoming.
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II.
DISCUSSION Interrogatory pertaining to Contention 3 Part 1:
Explain in detail how the NRC has taken into acccunt the prolonged effects of 40 years dewatering upon the plant subsoils and groundwater relationships? Provide the docu-ments which provide basis for this answer.
Part 2:
Did the FES analysis of potential radioactive release.to groundwater aquifers following a core melt accident take into into account possible weakening of intermediate soil layers--or other 40 year effects of dewatering? Explain.
Response to Part 1 The NRC Staff has considered the following information in its evaluation of the dewatering effects on the various plant subsoil layers at the Midland site over the estimated 40 years of plant operation.
a.
Because the long term dewatering will lower the groundwater level in the upper perched groundwater system to approximately el. 595 feet, there will be minimum effect to plant subsoils below this level which would include the approximately 150 feet thick preconsolidated impervious clay layer which separates the twc grotndwater systems.
The impervious clay layer has been shown by subsurface explorations to be located between approximately el. 580 feet and bottom el. 430 feet in the auxiliary buitding area, b.
In the depths of. subsoils which will be affected by dewatering, the Staff anticipates both improvements to the engineering propertiei of the foundation soils above el. 595 feet and certain adverse effects due to dewatering as discussed below.
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.* An increase in the shear strength of the subsoils' would reasonably c.
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be expected as dewatering would remove pore water and lower the water content of the foundation soils. This increased shear strength would result in higher margins of safety against bearing capacity type failures. The Staff has not required the app ~licant to j
estimate the improvement in safety if acceptable levels of safety I
l had been demonstrated under the more severe conditions (e.g.
non-dewatered condition).
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d.
Lowering the groundwater to levels below the walls of embedded structures will reduce lateral forces on foundations walls by removing water pressures. This reduction will result in an increase in structure stability.
r e.
The major disadvantage of dewatering on the plant subsoils is the removal of buoyancy.
This removal causes an increase in the e_ffective weight of the soils mass which in turn places greater loads on the foundation scih leading to greater soil compression.
I The Staff pursued resolution with the applicant of its concern for increased soil compression due to dewatering in letters to CPC dated March 21, 1979, September 11, 1979, and November 19, 1979, pursuant to 10 C.F.R. @ 50.54(f) (questions numbered 33,39(1),40(1),
41(2)(b),42(2)(e),44(2)and47(9)). The Staff is satisfied that the settlements estimated by the applicant to occur due to dewatering during plant operation are conservative and acceptable for use in structural analysis which evaluate the effects of these
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settlements.
In addition, long term settlement monitoring during l
plant operation will be carried out to verify that estimated i
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settlements are not being exceeded.
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f.
Another potential adverse effect of long term dewatering co~uld be' the removal of soil fines caused by lowering and pumping of the groundwater in the dewatering we?ls thereby causing large voids to form. The Staff's position has been, since the time dewatering was i
initially selected as a remedial measure, to ensure that a high l
quality dewatering system would be designed and properly controlled and installed in the field so as to avoid the loss of soil fines problem. The Staff efforts in this regard are documented in the above mentioned questions submitted pursuant to 10 C.F.R. 5 50.54(f)
(questions numbered 24, 47, 49, 50, 51, 52 and 53)., The Staff has met on several occasions and has participated in numerous conference calls with the applicant to resolve its safety concerns on the design and installation of the dewatering system. Two dccuments.
which summarize the Staff's review efforts are the letter of June 18, 1981 form R. Tedesco, NRC to J. Cook, Consumers Power Company and the letter of May 25, 1982 from D. Eisenhut to J. Cook.
Both letters are available in both the local public document room l
and the public document room in Washington D.C.
As a check on the acceptability of the dewatering system design,and field installation, the applicant has successfully completed the full scale field drawdown and recharge test. The monitoring for 9
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-5 loss of soil fines which has been completed with portions of both the temporary construction and permanent dewatering wells in operation has indicated that the dewatering system can safety operate and meet the required conservative acceptance criteria on loss of soil particles. The established criteria which ens'ures that the detrimental loss of soil particles will not occur requires that soil fines larger than 0.005 mm that are measured in the collected seepage water are not to exceed 10 parts per million.
If this level is reached during plant operation the applicant is required to determine which well or wells are causing the loss of fines and to stop pumping from the well(s).
If necessary, the problem well(s) will be repaired or replaced.
g.
In reviewing and evaluating the dewatering system, the Staff considered the effects that the system could have on groundwater levels in the lacustrine' sands which are located above the thick clay layer described in 1.'a. above. The Staff determined that water levels outside-of the plant fill area will no,t be significantly affected because the plant fill area is surrounded by an impervious.
trench and slurry wall and because water levels in the lacustrine sands will o,nly be lowered about 10 feet below what they were prior to plant operation.
The Staff notes that there~are no known groundwater supply wells in the lacustrine sands.
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6 Response to Part 2.
The foundation mats of the containment buildings at Midland are in an imperivous clay layer at an elevation of 572 feet. As explained in 1.a.
above, the clay layer has a top elevation of about 580 feet and a bottom elevation of about 430 feet. Thus the clay layer is about 150 feet thick. Since the dewatering system is designed to lower the groundwater to an elevation of 595 feet, groundwater levels during operation will remain about 15 feet above the top of the clay layer.
The meaning of the term " weakening of intermediate soil layers", as stated in the interrogatory is unclear to the Staff.
However, the Staff interpreted this to mean any changes to the intermediate soil layers which could result in contaminants reaching potential water users more rapidly or in higher concentrations. As explained in 1.e. above, one of the consequences of dewatering is an increase in the compressibility of the foundation clay layer. This increase in compressibility will in turn result in a corresponding decrease in the hydraulic conductivity (permeability) of the clay and make it more impervious.
However, these changes in compressibility and hydraulic conductivity will be small because the clay layer has already been preconsolidated by heavy glaciers over a long period of time.
Based on this information, the Staff concludes that the dewatering system will not result in any changes to the intermediate soil layers that could allow contaminants to reach potential water users more rapidly or in greater concentrations.
Thus, the Staff further concludes that the n
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liquid pathway effects of a core-melt accident would be similar whether the accident occurred during the first year of operation or after 40 years.
Respectfully submitted,
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i flichael N. Wilcove Counsel for NRC Staff Dated in Bethesda, Maryland this 3rd day of flovember 1982 I
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UNITED STATES OF AMERICA flVCLEAR REGULATORY COMIIISSION BEFORE THE ATOMIC SAFETY AND LICENSING APPEAL BOARD In the Matter of
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CONSUMER POWER COMPANY
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Docket No. 50 '329 OK & OL
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50-330 OM & OL (Midland Plant, Units 1 and 2)
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AFFIDAVIT OF JOSEPH KANE My name is Joseph Kane.
I am a principal geotechnical engineer, Hydrologic and Geotechnical Engineering Branch.
I am primarily responsible for providing the response to the first
. part of Intervenor Barbara.Stamiris' interrogatory pertaining to Contention 3, submitted to the Staff on August 30, 1982.
To the best of my knowledge and belief, the above information and the response to the above interrogaotry are true and cortect.
froseph Kane thisaftjandsworntobeforeme Subscribe day of Oct.,1982.
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T5tary Public My Commission expires: Qal4/ 6 #66
a UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION BEFORE THE ATOMIC SAFETY AND LICENSING BOARD 1
In the Matter of CONSUMERS POWER COMPANY
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Docket Nos. 50-329~0M & OL
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50-330 OM &.0L (Midland Plant, Units 1 and 2)
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AFFIDAVIT OF RAYM0ND 0. GONZALES fly riame is Raymond 0. Gonzales.
I am a Hydraulic Engineer in the Hydrologic and Geotechnical Engineering Branch of NRR.
In this i
capacity, my responsiblities include reviewing site flood levels and flood protection designs and nuclide migration of radioactive substances in surface and ground water.
I am primarily responsible for providing a response to the second part of Barbara Stamiris' interrogatory for contention 3, submitted to the staff on August 30, 1982.
To the best of my knowledge and belief, the above information and the responses to the above interrogatories are true and correct.
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ne this La,9nd sworn to before, 19 g Subscribed of(n,foi,o Nottary Fublic My conmission expires:
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c UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION BEFORE THE ATOMIC SAFETY AND LICENSING BOARD In the liatter of
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CONSUMERS POWER COMPANY
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50-330 OM & OL (Midland Plant, Units 1 and 2)
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CERTIFICATE OF SERVICE I hereby certify that copies of "NRC STAFF PARTIAL RESPONSE TO INTERVEN0R BARBARA STAMIRIS' INTERROGATORIES AND DOCUMENT REQUEST TO THE STAFF, DATED AUGUST 30, 1982" in the above-captioned proceeding have been served on the following by deposit in the United States mail, first class,.or, as indicated by an asterisk through deposit in the Nuclear Regulatory Commission's internal mail system, this 3rd day of November 1982:
- Charles Bechhoefer, Esq.
Frank J. Kelley Administrative Judge Attorney General of the State Atomic Safety and Licensing Board of Michigan'.
U.S. Nuclear Regulatory Commission Steward H. Freeman Washington, D.C.
20555 Assistant Attorney General l
Environmental Protection Division l
525 W. Ottawa St., 720 Law Bldg.
Lansing, Michigan t3913 Ms. Mary Sinclair 5711 Summerset Street Dr. Frederick P. Cowan Midland, Michigan 48640 Administrative Judge l
6152 N. Verde Trail Michael I. Miller, Esq.
Apt. B-125 Ronald G. Zamarin, Esq.
Boca Raton, Florida 33433 Alan S. Farnell, Esq.
Isham, Lincoln & Beale
- Dr. Jerry Harbour Three First National Plaza Administrative Judge 52nd Floor l
Atomic Safety and Licensing Board Chicago, Illinois 60602 l
U.S. Nuclear Regulatory Commission Washington, D.C.
20555 James E. Brunner., Esq.
Consumers Power Company 212 West Michigan Avenue Jackson, Michigan 49201 l
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e 2-Ms. Barbara Stamiris
- Atomic Safety and Licensing Board 5795 N. River U.S. Nuclear Regulatory Comission Freeland, Michigan 48623 Washington, D.C.
20555 James R. Kates
- Atomic Safety and Licensing Appeal 203 S. Washington Avenue Panel Saginaw, Michigan 48605 U.S. Nuclear Regulato'ry Coninission Washington, D.C.
20555 Wendell H. Marshall, President Mapleton Intervenors
- Docketing and Service Section i
RFD 10 Office of the Secretary Midland, Michigan 48640 U.S. Nuclear Regulatory Comission Washington, D.C.
20555 Wayne Hearn Steve J. Gadler, P.E.
Bay City Times 2120 Carter Avenue 311 Fifth Street St. Paul, MN 55108 Bay City, Michigan 48706 Frederick C. Williams Paul C. Rau Isham, Lincoln & Beale Midland Daily News 1120 Connecticut Avenue, NW 124 Mcdonald Street Washington, D.C.
20036 Midland, Michigan 48640 Lee L. Bishop Myron M. Cherry, p.c.
Harmon & Weiss Peter Flynn, p.c.
1725 I Street;.N.W.
Cherry & Flynn Suite 506 Three First National Plaza Washington, D.C.
20006 Suite 3700 Chicago, IL 60602 T. J. Creswell Michigan Division Legal Department Dow Chemical Company Midland, Michigan 48640 wb Michael N. Wilcove Counsel for NRC Staff "o
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