ML20010H835

Discusses Permanent Plant Dewatering Well Installation. Permanent Dewatering Well Schedule & One Oversize Drawing Encl.Aperture Cards Are Available in PDR

ML20010H835
Person / Time
Site:	Midland
Issue date:	09/16/1981
From:	Jackie Cook CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
To:	Harold Denton Office of Nuclear Reactor Regulation
References
13774, NUDOCS 8109290335
Download: ML20010H835 (7)

Text

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4 O Consumers Power James W Cook Comp 8ny na na,ua. - noyca,s,s.aa.,

< and Construction General Offices: 1945 West Parnalt Road, Jackson, MI 49201 + (517) 7880453 September 16, 1981 b M@/ N

.: Sp Mr Harold R Denton, Director g aa. ,H, Office of Nuclear Reactor Regulation 'W8 (U US Nuclear Regulatory Commission 4 p Washington, DC 20555 9 4

MIDLAND PROJECT DOCKET NOS 50-329, 50-330 PERMANENT PLANT DEWATERING WELL INSTALLATION FILE 0485.16 UFI 71*01, 00234(S) SERIAL 13774

REFERENCES:

(1) JWC00K LETTER TO HRDENTON SERIAL 11625 DATED MARCH 23, 1981 (2) JWC00K LETTER TO HRDENTON, SERIAL 11818 DATED APRIL 3, 1981 (3) RLTEDESCO LETTER TO JWC00K DATED APRIL 10, 1981 (4) JWC001( LETTER TO HRDENTON, SERIAL 11818A DATED APRIL 24, 1981 (5) RLTEDESCO IITTER TO JWC00K, DATED MAY 28, 1981 (6) JWC00K LETTER TO HRDENTON, SERIAL 12225 DATED MAY 28, 1981 (7) JWC00K LETTER TO HRDENTON, SERIAL 12243 DATED JUNE 8, 1981 (8) RLTEDESCO LETTER TO JWCOOK DATED JUNE 18, 1981.

(9) JWCOOK LETTER TO HRDENTON, SERIAL 13407 DATED AUGUST 10, 1981 (10) RLTEDESCO LETTER TO JWC00K DATED SEPTEMBER 2, 1981 ENCLOSURES: (1) TABLE 1 - PERMANENT DEWATERING WELL SCHEDULE (2) FIGURE 1 - PERM /NENT DEWATERING AND MONITORING WELL LOCATION PLAN We believe it is essential at this time that we proceed with the installation of the remaining 44 permanent dewatering wells which are identi ned in the enclosed twenty-five (25) copies of Table 1 and Figure- 1. We are writing to explain the necessity for well installation and testing in advance of the schedule indicated in Attachment 1 to our March 23, 1961 correspondence, (Reference 1) and to request NRC staff concurrence to altaw us to proceed with the installation of the remaining permanent dewatering vzilo.

In our previous correspondence of April 3 and 24,1981, May ' 8,1981, e June 8, 1981, and August 10, 1981 (Reference 2, 4, 6, 7, and 9, respectively) we forwarded complete technical details on the design, installation and testing of 20 permanent backup interceptor wells along with the quality assurance requirements applicable to these activities. We have also resolved NRC concerns and recommendations on this technical and quality assurance information. We have reviewed the draft Corps of Engineers letter of April 16, 1981, the deposition of J Kane, notes of the meeting with the staff on May 7, 1981 regarding responses te the 50.54(f) Questions 42(a), 47, 49, 50, 51, 52 and 53, and the concerns and recommendations identified in the NRC's correspondence of April 10 and May 28, 1981 (References 3 and 5). Most oc0981-0428a100 l 8109290335 810916 Edi I PDR ADOCK 05000329 gi $f A PDR [

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concerns have already been resolved in discussions with the staff regarding installation of the 20 backup inteceptor wells which is detailed in Section 10 of Specification C-88(Q). These concerns included gravel pack material, gradation of foundation materials, soil particle monitoring, incremental withdrawal of casing during gravel pack and grout placement, advancement of hole below casing, and recordkeeping durint well installation and development.

The staff's concurrence on the installation of these 20 backup interceptor wells was contained in two letters dated June 18 and September 2, 1981 i (References 8 and 10). Based on our responses to these staff concerns we are not aware of additional staff concerns that would preclude our proceeding with the installation of the remaining permanent dewatering wellt.

The remaining 44 permanent dewatering wells, consisting of 24 area wells and 20 interceptor wells, will be installed in the locations shown on the enclosed Figure 1 and to the depths listed in Table 1. Figure 1 and Table 1 are updates of the 50.54(f) Figure 47-11 and Table 47-2, respectively. It is important to note that Specification C-118(Q) for the installation of these l remaining wells has been prepared based on the technical requirements given in response to 50.54(f) Question 47-4 and on modifications to reflect the comments provided by the staff regarding Section 10 of C-88(Q) for the permanent backup interceptor wells. Therefore, Specification C-118(Q) is technically equivalent to Specification C-88(Q), Section 10, which has already been reviewed by the staff. The well design is the same as that provided in response to Question 47-4, except that: (1) grout is now specified for the surface seal; (2) the surface seal is a minimum of 18 feet thick; (3) minimum hole size is 16 inches; and (4) 87% of the filter pack is permitted to be retained on the Number 40 sieve. The interceptor and backup interceptor well locations have been modified primarily in the service water pump structure area to accommodate the planned underpinning which was presented to the staff in a meeting on May 7, 1981, and to take advantage of the thick sequence of natural sand found further from the building which was mentioned in our telecommunications of June 17, 1981 with the staff. The locations of the area wells have been modified only slightly to avoid underground utilities and to accommodate the aforementioned changes near the service water pump structure.

Also the location of Monitoring Well 4 and area Well B-2 have been interchanged as shown on Figure 1. The revised elevations corresponding to these changes for top of screen, bottom of screen and bottom of filter pack are indicated in Table 1. Moreover the same quality assurance prograc will be applied to this work as is being applied to the installation of the 20 backup interceptor wells. The Specification C-118 along with the quality program requirements applicable to this work will be made available at the site for the NRC's review.

Also identified on Figure 1 are the intended locations of well pilot holes for boring samples. Pilot holes will be drilled at permanent well locations that are not near one of the following: 1) a previously drilled permanent dcwatering boring (PD-Series); 2) an existing pilot hole; or 3) a planned pilot hole. Sand samples from the pilot holes will be tested for gradation to verify the gravel pack design.

Because preparatory work on underpinning of the auxiliary building is currently scheduled to begin in January 1982, we wish to complete the installation of the remaining 44 permanent dewatering wells prior to this date oc0981-0428a100

so that the maximum benefit will be derived from these permanent wells. We have already started pilot hole drilling for the remaining 44 permanent wells during the week of September 8, 1981, and we anticipate starting the retaining well drilling in October. At our current rate of production, completica of the permanent wells, including development and testing, can be accomplished before the start of the auxiliary building underpinning provided that we proceed immediately. Although installation of the petmanent wells could be accomplished during the auxiliary building underpinning, well development and testing could not be performed. This is due to the expectation that the temporary construction dewatering system will lower site water levels Lelow j that necessary to perform proper well development and testing. Because it is not prudent to install wells that will not be developed or tested until a much later date, it becomes essential that we proceed with the start of this work so that the completion of the permanent dewatering system will not have to be delayed until after underpinning which is scheduled for completion in 1983.

In addition, based on a review our commitments in the 50.54(f) responses, we have concluded that proceeding at this is required to allow us to establish our monitoring procedures, test criteria, maintenance plans, etc, for plant operation based on the experience gained with the remaining permanent wells during the latter stages of plant construction as well as during their use to support the temporary dewatering required for the auxiliary building underpinning construction.

We anticipate that the start of well drilling in Ocober 1981 will coincide with the beginning of the recharge test for the initial 20 backep interceptor wells already in progress. Well drilling could begin on any of the 44 remaining permanent wells because the water table elevation has no bearing on the drilling operation. Although water is added during the drilling process to prevent hole instability and to facilitate removal of drill cuttings, the quantity of water lost is very small. The permeability of the clay is 0.04 ft/ day and the permeability of the sand is 3.5 ft/ day; please refer to our 50.54(f) response to Question 47-2. Because the subcontractor will not be permitted to drill the hole below the bottom of the casing when penetrating sand, the cross sectional area available for seepage will be a maximum of only 1.8 square feet based on an 18-inch hole size. In fact, no seepage losses have been observed during the current well drilling program. Because groundwater is removed during development and testing, this phase of the work will not begin until after the recharge test is completed.

We believe that the previous information supplied to the staff on both the technical and quality program aspects of the dewatering well design, installation and testing combined with the further information contained in this correspondence should be sufficient to obtain the NRC staff's concurrence with our request to proceed with the installation of the remaining 44 dewatering wells.

JVC/RLT/cr oc0981-0428a100

4 CC Atomic Safety and Licensing Appeal Board, w/o CBechhoefer, ASLB, w/o MMCherry, Esq, w/o RJCook, Midland Resident Inspector, w/o Dr FPCowan, ASLB, w/o RSDecker, ASLB, w/o DHood, NRC, (2) w/a DFJadd, B&W, w/o TDKane, NRC, w/a FJKelley, Esq, w/o RBLandsman, NRC Region III, w/a WHMarshall, w/o W0tto, US Army Corps of Engineers, w/a WDPaton, Esq, w/o HSingh, Army Corps of Engineers, w/a BStamiris, w/o I

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oc0981-0428a100 L ______ _

Midland Plent Enclosure 1 Serial 13774

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s TABLE 1 FERMANENT DEWATERING WELL SCHEDULE (1)

El. Top of El. Bottom of El. Bottom of W11 Number Screen (f t.) Screen (f t.) Filter Pack (ft)( }

Interceptor Wells 602 587 582 C-1 C-2 598 588 583 599 589 584 C-3 C-4 600 590 585 602 592 587 C-5 586 565 560 D-1 589 565 560 D-2 589 565 560 D-3 590 565 560 D-4 D-5 588 570 565 587 575 570 D-6 587 579 574 D-7 600 590 585 E-1 600 585 580 E-2 600 580 580 E-3 600 580 580 E-4 600 580 580 E-5 600 580 580 E-6 600 580 575 E-7 600 590 585 E-8 600 590 585 E-9 Back-up Interceptor Wells 586 565 560 F-1 589 565 560 F-2

$89 565 560 F-3 590 565 560 F-4 588 570 565 F-5 587 575 570 F-6 587 579 374 F-7 602 578 573 G-1 602 575 570 G-2 602 575 570 G-3 600 572 567 G-4 600 570 565 G-5 600 575 570 G-6 597 587 577 G-7 587 573 568 G-8 585 574 569 G-9

, - Midland Plant Enclosure 1 Serial 137/l l

, TABLE 1 (Continued)

PERMANENT DEWATERING WELL SCHEDULE ( )

Well El. Top of El. Bottom of El. Bottom of Number Screen (f t.) Screen (ft.) Filter Pack (ft)

Fack-up Interceptor Wells (corntsed)

H-1 601 565 580 H-2 600 587 582 H-3 601 595 580 H-4 603 597 582

/.- ea Wells 600 580 575 A-1 A-2 600 575 570 600 575 570 A-3 A-4 600 580 575 594 576 571 A-5 B-1 600 565 575 600 590 575 B-2 600 590 575 B-3 B-4 623.5 590 575 600 590 580 B-5 600 S75 570 J-l 595 $75 570 J-2 600 575 570 J-3 600 575 570 M-1 580 565 560 M-2 590 575 570 M-3 600 575 570 M-4 595 575 570 M-5 600 575 570 N-1 600 575 570 N-2 590 575 570 N-3 600 575 570 N-4 600 575 570 N-5 585 570 565 N-6 Final elevations may vary depending on actual field conditions and results of pilot holes.

( ) Elevation at botto'a of filter pack is the elevation of bottea of the hole.

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