ML20054G115

Forwards Suppl to 820611 Response to Enclosure 8 of NRC 820525 Request for Addl Info to Complete Review of Soils Remedial Work

ML20054G115
Person / Time
Site:	Midland
Issue date:	06/14/1982
From:	Jackie Cook CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
To:	Harold Denton Office of Nuclear Reactor Regulation
References
17319, NUDOCS 8206210118
Download: ML20054G115 (67)

Text

{{#Wiki_filter:. f @ C0mpaRY t CORSUERBIS Povver Jamies W Cook vu r,,,u - r i. s.,e a.d Co.struction oeneret offices: 1946 West Pernha Road, Jockeon, MI 49201 e (617) 788-0453 June 14, 1982 liarold R Denton, Director Office of Nuclear Reactor Regulation Division of Licensing US Nuclear Regulatory Commission Washington, DC 20555 MIDLAND PROJECT MIDLAND DOCKET NO 50-329, 50-330 RESPt'(SE TO NRC STAFF REQUEST FOR ADDITIONAL INFORhTION REQUIRED FOR COMPLETION OF STAFF REVIEW 0F SOILS REMEDIAL WORK FILE: 0485.16 SERIAL: 17319

REFERENCES:

(1) D G EISENHUT LETTER TO J W COOK ' DATED MAY 25, 1982 (2) J W COOK LETTER TO H R DENTON, SERIAL'17293, DATED JUNE 1, 1982 ENCLOSURE: RESPONSE 70 TIIE NRC STAFF REQUEST FOR ADDITIONAL INFORMATION REQUIRED FOR COMPLETION OF STAFF REVIEW OF SOILS REMEDIAL WORK DATED JUNE 14, 1982 ' to the NRC's correspondence of May 25, 1982 (Reference 1) listed the information which the Staff required to conclude its review of the soils remedial work. We responded in our correspondence of June 1, 1982, and indicated that our response to the questions posed in Enclosure 8 would be forwarded by June 15, 1982. The enclosure to this correspondence represents a complete response to each L, question posed in Enclosure 8 to the NRC's letter of May 25, 1982. Supporting l information is available for audit by the NRC at Bechtel's office in Ann Arbor. We believe the enclosed information, combined with the discussion of these responses with the Staff on June 11, 1982, adequately responds to the requests and individual concerns identified by the Staff. With the submittal of the 0! 0 l oc0682-0123a100 h206210118 820614 DR ADOCK 05000329 PDR

.i 2 enclosed information, we believe that the Staff should be in a position to expeditiously review our responses and immediately thereafter provide its concurrence with our request to proceed with the remedial measures. JWC/RLT/mkh CC Atomic Safety and Licensing Appeal oard, w/o CBechhoefer, ASLB, w/o tir! Cherry, Esq, w/o FPCowan, ASLB, w/o RJCook, riidland Resident Inspector, w/o RSDecker, ASLB, w/o SGadler, w/o Jllarbour, ASLB, w/o Gilarstead, liarstead Engineering, w/a DSHood, NRC, w/a (2) DFJudd, B&W, w/o JDKane, NRC, w/a FJKelley, Esq, w/o RBlandsman, NRC Region III, w/a Wiltfarshall, w/o JPflatra, Naval Surface Weapons Center, w/a W0tto, Army Corps of Engineers, w/a WDPaton, Esq, w/o SJPoulos, Geotechnical Engineers, w/a FRinaldi, NRC, w/a llSingh, Army Corps of Engineers, w/a BStamiris, w/o oc0682-0123a100

CONSUMERS POWER COMPANY Midland Units I and 2 Docket No 50-329, 50-330 Letter Serial 17319 Dated June 14, 1982 At the request of the Commission and pursuant to the Atomic Energy Act of 1954, and the Energy Reorganization Act of 1974, as amended and the Commission's Rules and Regulations thereunder, Consumers Power Comp my submits additional information responding to NRC requests on the soils remedial work. The submittal documents our response to information requested by the NRC Staff in Enclosure 8 of the NRC's May 25, 1982 correspondence. l CONSUMERS POWER COMPANY BY Jr Projec/ W Cook, Vice Pres,r - ident 2 ts, Engineering and Construction Sworn and Subscribed Before Me This 14th Day of June 1982 w ks ~ -Notary Pub'lic j Jackson County, Michigaa j My Commission Expires September 8, 1984 r I 1 miO682-0123b100

t~ 7o ENCLOSURE RESPONSE TO THE NRC STAFF REQUEST FOR ADDITIONAL INFORMATION REQUIRED FOR COMPLETION OF STAFF REVIEW OF S0ILS REMEDIAL WORK MIDLAND PLANT UNITS 1 AND 2 DOCKET NO 50-329 and 50-330 CONSUMERS POWER COMPANY June 14, 1982 miO682-0120a100

Y 'q 4 RESPONSE TO THE NRC STAFF REQUEST FOR ADDITIONAL INFORfATION REQUIRED FOR COMPLETION OF STAFF REVIEW OF S0ILS REMEDIAL WORK INFORMATIONAL REQUEST 1 Provide the following information regarding the Auxiliary Building and Feed-water Isolation Valve Pits: REQUEST 1.1 Redesign of stiffened bulkhead against earth pressures during drift excavation to install needle beam assembly.

RESPONSE

Our response to this request was contained in the enclosure to Serial 17225 dated May 14, 1982 and is duplicated below along with the NRC's question: Review Concern 14 - Explain the design for the initial drift tunnel extended under the end of the electrical penetration area for piers W8 and E8 to the Units 1 and 2 reactor walls, respectively. Response - The initial drifts will be constructed with the cross-section shown in Figure 3. As noted in Figure 3, a provision is made to eliminate the effect of surcharge loading from the building. The drift is designed for the active earth pressure (I) because the fill behind the wall uses a 4-foot set spacing for the drift bracing. The actual drift construction will use a 2-foot set spacing, which has the earth pressure; the actual drift will then be designed for twice the earth pressure. ( ) Maximum value = 41h PSF where "h" is the height of the drift i i miO682-0120a100 l

'f t REQUEST 1.2 Revise report on crack evaluation to include consideration of the effects of multiple cracks.

RESPONSE

Several crack evaluation reports, as noted below, have been submitted previously. A final report, issued by our correspondence Serial 17320 dated June 14, 1982 is being submitted to address the criteria pertaining to crack width and the effects of multiple cracks. B_1dg Date Serial 1 FIVP 1/25/82 15493 Aux 1/29/82 15527 DGB 2/16/82 15978 SWPS 3/2/82 16009 REPAIR 4/30/82 17228 i i i miO682-0120a100

9* 4 6 e 3 REQUEST 1.3 Analysis of the construction condition using a subgrade modulus of 70 KCF and provide results.

RESPONSE

Our response to this request was contained in Enclosure 2 to Serial 17304 dated June 7, 1982 and is identified as Review Concern 2 for the Construction Phase 3. miO682-0120a100

4 REQUEST 1.4 Allowable differential settlements for Phase 3 (based on 1.3 above)

RESPONSE

The locations at which the differential settlements will be monitored and the allowable values and the technique used to calculate these values are as follows. The additional Bench Marks (B/M) have not been installed. The allowable values may slightly change as As-Built locations of these B/M are incorporated in calculat.ons. a. Locations of Deep Seated B/M Drawing 7220-C-1493 (provided with Serial 17304 dated 6/7/82) now shows all building instrumer.tation, has revised formula for calculating A1, and the three new DSBs. The three new DSBs are DSB-AS2, DSB-AS3, and DSB-AS4. DSB-AN2 was provided in the railroad bay to provide redundancy to the existing DSB-ANI. DSB-AS3 and DSB-AS4 are being located near Column Line G. In the north-south direction, the main auxiliary building north of Column Line G is more rigid than the portion between Column Lines G and II. Therefore, it is more accurate to measure relative displacements (al) with respect to DSB-AS3 and DSB-AS4 rather than DSB-ASI and DSB-AS2. b. Results of Calculations The allowable relative vertical structural displacements between the DSBs near Column Line G and the DSBs near the south wall of the electrical penetration area (EPA) and of the control tower are shown in Table 1.4. To arrive at the allowable relative displacements, the calculated existing miO682-0120a100

i e S structural displacements were subtracted from the displacements obtained from the analyses described in Part d of this response. TABLE 1.4 Allowable Relative Vertical Soil Subgrade Modulus Under Displacment, W1 (in) Main Auxiliary Building DSB-2E DSB-3E DSB-3W DSB-2W 30 kcf (See Fig 1.4.2) 0.67 0.76 0.72 0.68 70 kcf (See Fig 1.4.3) 0.63 0.73 0.71 0.56 The locations of the DSBs are shown in Figure 1.4.1. All the relative displacements are with respect to the reference point near Column Line G. Tha compatibility of the floor / roof beam connections to these building displacements is being reviewed. Because allowable displacements are slightly smaller for the subgrade modulus (k=70 kcf), the allowable deflections to be used in the field for the construction will be based on the subgrade modulus (k=70). Construction would be stopped at the allowable displacement limits. An evaluation of the construction will be made at a lower level of displacement. These lower level displacements are termed " trigger limits." The trigger limits will be established at lower than one-half of the allowable displacements. l The values in Table 1.4 are larger than the corresponding values presented to the NRC in the meeting of February 26, 1982, at Bethesda, Maryland. The reasons for this increase are as follows: miO682-0120a100 t

i e 6 1. As noted in the February 26 meeting, the results presented were based on the first iteration of the analysis. However, the results presented now are based on the last iteration of the analysis. 2. The reference point DSBs have been moved north toward the railroad bay, thus increasing the north-south distance between the reference DSBs (near Column Line G) and the DSBs near the south edge of the control tower and EPAs. c. Discussion of Significance of Results The allowable vertical relative displacements shown in Table 1.4 are the allowable structural deformations for the south edge of the control tower and EPAs with respect to Column Line G. For the loading (unfactored dead weight of the structure, blockwalls, equipment, and 25% of live load), the structure deflects to the south because the control tower and the EPAs are founded on fill material. Figure 1.4.4 shows the deflection curve under 'd the a, ed loads. Because of the relatively higher structural stiffness between Column Lines A and G, the displacement variation between Column Lines A and G was considered to be linear. The difference in displacement between the DSBs adjacent to Column Line Kc and G also include the rigid body tilting. The structural deformation Al for DSB-3E is computed as follows: A1=AKc-(AG+AG{g x L2) AA = AKc - (1 + )AG + x AA = A(DSB-3E) - (1 + ) A(DSB-AS4) miO682-0120a100

7 = AKc - (1 + )AG + x AA =A(DSB-3E)-(1+ff3EAS})A(DSB-AS4) A 1) +ffjN1)xA(DSB-AN1) (format used in Drawing 7220-C-1493) where: L1 = L(AS4,AN1) = north-south horizontal distance between (DSB-AS4) and (DSB-AN1) L2 = L(3E,AS4) = north-south horizontal distance between (DSB-3E) and (DSB-AS4) AKC = A(DSB-3E) 1 l AG = A(DSB-AS4) AA = A(DSB-ANI) f As (except A1) are the absolute vertical deflections at the DSBs. The i structural deformations Al for DSB-2E, DSB-3W, and DSB-2W are computed in a similar manner. i miO682-0120a100

8 d. Calculation Technique The allowable relative vertical displacements shown in Table 1.4 were determined from a nonlinear analysis of the structure performed to include the effects of concrete cracking. A linear finite-element program, BSAP CE800, was used. To achieve the effect of non-linearity, an iterative process was used. A three-dimensional, finite-element model was used for the analyses. This model was discussed with the NRC structural staff and a copy of the model was provided to the staff during the NRC audit held at Bechtel's Ann Arbor office on February 1 through 5, 1982. The purpose of the analyses is to arrive at the relative displacements which the structure can tolerate. In these analyses, relative displacements were induced by eliminating the soil springs to represent the first stage of soil removal and by reducing the stiffness of certain soil springs representing the fill under the EPAs and the control tower. The flow diagram (see Figure 1.4.6) shows the step-oy-step procedure for 1 the analyses. Criteria and assumptions for the analyses are presented below: 1. Ec value: Same as ACI 318 (no reduction) 2. Reduced stiffness: In the cracked areas, the reduction in stiffness based on rebar. Initial crach based on 3/fe' for shear and 4]fc' for tension. miO682-0120a100 i i

9 Criteria 1 and 2 rere discussed and agreed upon with the NRC during the staff audit held at Bechtel's Ann Arbor office on March 16 through 19, 1982.. These criteria are shown on Attachment 2 to the letter from Consumers Power Company to the NRC, File 0485.16, B3.0.1, Serial 16597. 3. Convergence would be assumed to be achieved when the following criteria are met. The number of elements to be cracked continues to progressively a. reduce. b. The number of elements to be cracked based on the last computer run is not more than 10% of the total number of elements cracked. 4. The average strain in the cracked elements is limited to two-thirds of the yield strain. miO682-0120a100

AUXILIARY BUILDING UNDERPINNING DEEP SEATED l BENCH MARK LOCATION PLAN

• i t

l l 2 DSB AN2e e l C 7 i 1 DSB-AS3 e DSB-AS4 e DSB-AS1 DSB-AS2 e \\M \\.d ~ DSB-2W

• DSB-3W e e'DSB-3E
• DSB-2E 5.3 6.6 7.8 FIGURE 1.4.1 1

l

• Exact locations are shown on drawings C-1490 and C-1491 G-2518 02 I

j

~ AUXILIARY BUILDING UNDERPINNING I l 1 k = sKW l s f k = 30KW \\ 1 Y / \\ A d / k = 1sKW g 4 I k = 17KCF k = 21KCF ,= w ,~. a. 5.3 g,g 7, em t et FIGURE 1.4.2 ASSUMED EXISTING SOIL SUBGRADE MODULUS AuxtiAnv outmosG UNDERredNH3 1126/s2 FOR SOIL UNDER TIIE AUXILIARY BUILDING

AUXILIARY BUILDING UNDERPINNING 1 I k = sKCF i i OC f I .i k = 70 ef k i. e / k=18KCF \\ g k = 17KCF k=21KCF g,yMCF g' gMCF s.3 s.s 7.s m miet FIGURE 1.4.3 ASSUMED EXISTING SOIL SUBGRADE MODULUS AuxtAnvauumeGUNDEMNN96 ffws2 VALUES FOR SOIL UNDER THE AUXILIARY BUILDING

x l I l l l Control Tower Main Auxiliary Building 4 + 3 4 6 1 1 5 + f 1 T 2 t t > L L 2 1 Displacement due to til f f. -C s a A C 2c - - - - - ~,,. - ~~~~ After iterations K 'j c g / 1 Reference point Relative displacement adjusted for tilt j g ,g G A i 1 x L2 L1 i FIGURE 1.4.4 DEFLECTION CURVE AND STRUCTURAL DEFORMATION

AUXILIARY BUILDING UNDERPINNING CONSTRUCTION SEQUENCE STAGE - 1 N g SUPPORTED ON TILL s s,,, nn s,,, i > > e, si n l ACTUAL EXCAVATION st12' 4 s ' ' ~ s' SUPPORTED ON \\ \\ EXISTING FILL l / / N M N l b / / 20' SOIL SPRINGS l REMOVED IN I ANALYSIS ELECTRICAL PENETRATION AREA (EPA) CONTROLTOWER l (WEST) j I EUARY Up EERP99GNG li2 essa FIGURE 1.4.5 e sur as

l l ANALYSIS SCHEME 1 START 1 First stage soll removal analysis results (Fig 5) identify the elements which can be considered cracked based on criteria 2 i 4 i For the cracked elements, use stiffness based on robar (see Criteria 2) a 6 I Analysis 1 1 i j No Yes Convergence? g l (See Criteria 3) '( f 4 Figure 1.4.6 I G 251841

~ i 10 REQUEST 1.5 i Horizontal movement acceptance criteria for Phase 3 for instruments at top of EPAs and control tower.

RESPONSE

Our response to this request along with the NRC's question was contained in Serial 16597 dated March 31, 1982 and is summarized as follows: Review Concern 1 - Provide instrumentation details and horizontal movement tolerance criteria with basis, for 3 instruments to be installed at top of EPA's and Control Tower (Telephone record, March 8,1982 Par. 4.c and Par. 5). Response - Three relative movement devices will be provided to measure the horizontal movement between the turbine building and the auxiliary building. These devices are as follows: Unit 1 EPA to Turbine Bldg el 705 DMD-11 Control Tower to Turbine Bldg el 705 DMD-12 Unit 2 EPA to Turbine Bldg el 705 DMD-13 These devices will be installed and read for background during phase 2A and 2B. Acceptance criterial will be established for Phase 3. Each monitoring point will be treated as a separate data base. The monitoring details are shown on drawing C-1493(Q) (Figure 4). miO682-0120a100

o 11 REQUEST 1.6 As-built report with confirmatory detail on underpinning in FSAR upon completion of construction.

RESPONSE

Upon completion of the underpinning a report will be prepared and submitted addressing the as-built condition of the underpinning and structures. This report will be submitted within 6 months after the completion of construction. ) l l I miO682-0120a100 l ~.

12 REQUEST 1.7 Acceptance criteria for strain monitors for Phase 3 i

RESPONSE

4 ) The acceptance criteria for strain monitoring is shown in Attachment 5-3 (Dwg i 7220-C-1493) to Serial 17304 dated June 7, 1982. (Review Concern SE), 1 i 2i I i ') .1 I, J t i 4 i I 1 a f i t miO682-0120a100 4 i a --.,y. y4 y__.____ y_ y, -,n y -r

13 REQUEST 1.8 Acceptability of 1.5 FSAR SSE versus SSRS as bounding design.

RESPONSE

The underpinnings for the Auxiliary Building and the Service Water Pump Structure (SWPS) and the new ring beam for the Borated Water Storage Tank (BWST) are required to be designed so as to withstand the forces from the earthquake characterized by the Site Specific Response Spectrs (SSRS). Since, during the initial design phases of the underpinnings and the new ring beam, final staff concurrence on the SSRS was not yet available, a conservative assumption was made for the design. The seismic forces used in the design were obtained by multiplying the results from the analysis using Midland FSAR design SSE spectra with median soil case by a factor of 1.5 Since Staff concurrence on SSRS was subsequently obtained studies were performed to show that the assumed seismic response on the underpinnings and the new ring beam would be more than the response obtained by using SSRS input which would result in a conservative design. The studies for the auxiliary building and SWPS compared the nodal vector accelerations from an analysis using the Midland FSAR response spectra and l nominal soil case multiplied by a factor of 1.5 to the nodal vector accelerations from an analysis using the SSRS and Midland FSAR envelope response spectra together with three soil cases, ie, nominal and plus or minus 50%. The comparisons were made for selected key nodes which are representative of the governing structure responses, miO682-0120a100

14 For the auxiliary building underpinning, the significant node for comparison is node 66 (free end of the electrical penetration areas at elevation 695'). FSAR x 1.5 Node <SSRS & FSAR> 66 1.22 < > I Envelope of response spectra curves The same ratios for the remaining portions of the underpinning were more conservative. For the SWPSs, the most significant node for comparison is node 14 (foundation level of the lower base slab at elevation 589.5'). FSAR x 1.5 Node <SSRS & FSAR> 14 1.15 The same ratios for the remaining portions of the building underpinning were more conservative. For the BWST, the comparison used the largest acceleration from both the including bottom pressure (IBP) and the excluding bottom pressure (EBP) cases. However, the EBP case is used to calculate forces on the tank and IBP case is used to calculate forces on the foundation. The largest acceleration for the ISP case was used to calculate base shear. When this was done, the base shear due to the SSRS-FSAR envelope, was 2% less than the FSAR base shear multiplied by 1.5. All other shears and moments on the foundation due to the SSRS-FSAR envelope were less than those caused by the FSAR multiplied by 1.5 1 In conclusion, the 1.5 x FSAR response spectra analysis is conservative for the auxiliary building and the SWPS underpinnings, and the BWST foundation. 1 i miO682-0120a100 -e

15 REQUEST 1.9 Method to be followed for transfer of Jacking load into permanent wall.

RESPONSE

The detailed final load transfer procedure is currently under development. The final loads in the jacking groups have been finalized and the structure found to be acceptable. The intermediate increments of loads in the jacks are being finalized. A brief overview of the anticipated procedure is as follows: (See Figure 1.9-1): 1. Install three groups of jackstands on the permanent underpinning wall under the east and west EPAs a) Group 1 (jacks 1 through 9) will carry 2800 kips, the load supported by the grillage system at pier 8 b) Group 2 (Jacks 10 through 22) will carry 2860 kips, the load supported by the grillage system at pier 5 c) Group 3 (jacks 23 through 36) will carry 3630 kips, the load supported by the grillage system at pier 2 2. Add a predetermined portion, which is being finalized, of load to Groups 1 and 3. 3. Remove the same load from the grillage 2 and 8 jacks. 4. Monitor the grillage 5 Jacks and the group 1 and 2 jacks. miO682-0120a100

4 Q 16 a) If the pressure in the grillage 5 jacks increases, Jack an additional load that corresponds to this increased pressure into Groups 1 and 3 jacks to decrease the pressure in the Grillage 5 jacks to their original pressure. b) If the pressure in Group 1 and 2 jacks increases after removing the load from the grillage 2 and 8 Jacks, convert the pressure to load and subtract this load from the next step. 5. Repeat steps 1 through 4 until all loads on the grillage 2 and 8 jacks have been transferred to the Group 1 and 3 permanent jacks. 6. Remove a predetermined amount, which is being finalized, of load from the grillage 5 jacks. The pressure in the Group 1 and 3 permanent jacks will increase. 7. Increase the load in the Group 2 permanent jacks until the pressure in group 1 and 3 jacks is reduced to the pressure at the end of step 5. 8. Repeat steps 6 and 7 until about 50% of the load on grillage 5 jacks is transferred to the group 2 permanent jacks. 9. Install group 4 jacks along column lines 5.3, 7.8, Kc, and H. Group 4 k jacks in the final condition will carry loads as follows: a. Walls on column lines 5.3 and 7.8 will carry loads of 4165 kips each. b. Wall on column line K will carry 8250 kips. c c. Column line H will carry 970 kips. k miO682-0120a100

Vl_ 17 ~_x"

10. Reduce the pressure in the jacks on the H and CT piers a k

predetermined amount, which is being finalized, the pressure in group 1, 2 and 3 Jacks will increase. 1

11. Increase the load in the group 4 permanent jacks until the pressure in group 1, 2 and 3 jacks is reduced to the pressure at the (ad of step 8.

P ers and the j_

12. Repeat steps 10 and 11 until all load from the H i

k desired load from the CT piers is transferred to the group 4 F permanent jacks. LL

13. Repeat Steps 6 and 7 until the remaining load on the grillage 5 jacks is transferred to the group 2 permanent jacks.

r-

14. If movement of the EPA or control tower occurs at any time during load transfer, proceed as follows:

r -q a. If downward movement of the EPA at the end of grillage 8 relative to the end of grillage 2 end occurs, engage X-1 and X-2 jacks. b. .If downward movement of the EPA at the end of grillage 2 relative --{ to the end of grillage 8 end occurs engage X-3 and X-4 jacks. q} c. If downward movement of the ends of either grillage 2 or 8 continues, re-engage the grillage 2 or 8 jacks respectively. ? d. If downward movement of the control tower at K line relative to c H line occurs, increase the active system pressure. _Lh d miO682-0120a100 MT l

l l 18 l l e. If downward movement at the control tower at K line still continues, re-engage all grillage jacks. i w i. Ii \\ \\ 'eiO682-0120a100 P

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19 l l 1 i REQUEST 1.10 t Complete design analyses of permanent underpinning wall. 4 j Our response to this request'was contained in an enclosure to Serial'17304 dated June 7, 1982 and is identified as Review Concern 2 for Construction i Phase 4 4 } } i i i l 1 i 1 i 4 2 ) 4 i i s f I -i ) i I miO682-0120a100 i 4

20 REQUEST 1.11 Updated construction sequence for Phases 3 and 4.

RESPONSE

The construction sequence for Phase 3 was provided in our previous correspondence Serial 17225 dated May 14, 1982. The construction sequence for Phase 4 is being prepared. A summary description of the preliminary sequence is provided below. 1. The south wall under column line K, incorporating piers CTI through CT12 c and the walls connecting CT13, CT14, and CT15 to the K line wall will be c constructed. 2. The north-south walls on column lines 5.3 and 7.8 under the control tower and the walls under the EPA will be constructed. Horizontal construction joints will be provided at suitable heights to remove temporary struts between reactor building foundation and piers under the turbine building. These struts will be replaced by shorter struts to accommodate the wall. The walls will be constructed up to approximately elevation 598'. At this time, closure strips will be left at column lines H and K ' c 3. As the walls constructed under the control tower reach an approximate elevation of 582 ft., the area will be backfilled and the diaphram slab at el 584 will be constructed and connected to the walls on column lines H and K. The lower level struts will be removed before constructing the I slab. miO682-0120a100

21 4. At the end of Step 2, the weight of the EPA and control tower will be transferred sequentially from the temporary to permanent supports as described in response to Item 1.9. 5. Following load transfer in Step 4, temporary support girders will be removed. The structure will then be supported on permanent walls for at least 30 days or until the acceptance criteria for soil settlement is satisfied. 6. During the period following load transfer, backfilling with compacted granular material will be performed. 7. As construction proceeds, dowels will be inserted from the top or rock bolts drilled to the underside of the existing foundation at suitable intervals and grouted. At the same time, horizontal dowels between the vertical faces of the underpinning walls and the permanent structure on column line H below elevation 614' will be drilled and grouted. 8. At the end of Step 6, the gap between the undersides of the superstructure and top of the underpinning walls will be backfilled with concrete and grouted. At this time, the closure strips described in Step 2 will be concreted and grouted and the upper level struts und2r pier CT will be removed. 9. The backfilling of access drifts will be sequenced to suit construction. miO682-0120a100

22 REQUEST 1.12 Settlement monitoring program to be required during plant operation with action levels and remedial measures identified (Tech. Spec.). Include RBA, EPA and Control Tower.

RESPONSE

The proposed Technical Specifications for the Midland Plant Units 1 and 2 are currently under development by Consumers Power Company for both incorporation into FSAR Chapter 16 and as the basis for issuance of OL Appendix A. The Company anticipates submitting these proposed Technical Specifications for NRC review in the Fall of 1982. The Technical Specification addressing settlement of all Seismic Category I plant structures will be submitted as a part of the overall proposed Technical Specification for the Midland Plant. This Technical Specification will meet the requirements of Section 50.36, " Technical Specifications," of 10 CFR Part 50 " Domestic Licensing of Production and Utilization Facilities." Limiting conditions for plant operation (LCO), which will be applicable to all modes of operation, will be set forth for each Seismic Category I structure. Calculated settlement values (based on ultimate design) for each structure will be set forth in the LCO. (These values may have to be revised based on As-Built conditions to be assessed six months af ter the completion of underpinning as stated in response to Item 1.6.) Settlement values set forth in the LCO as requiring actions will be conservatively based on a fraction of the acceptable settlements for each Seismic Category I structure. miO682-0120a100

23 Should a LCO settlement value (action limit) be reached or exceeded, the Technical Specification will require that a settlement evaluation be completed and the investigation results and conclusions submitted to the NRC within a specified time period. The conclusions of this settlement evaluation will detail additional actions required to ensure protection of the health and safety of the public. Utilizing this approach will provide for the implementation of appropriate remedial measures which are dependent on the nature of the settlement. The surveillance requirements section of the Technical Specification will address the settlement monitoring program. Survey settlement measurements for all Seismic Category I structures & tanks will be conducted at the frequency indicated in FSAR Section 2.5.4.13.2 on monuments to be specified in the surveillance requirements section. These measurements will provide a record of settlements experienced versus time and will be utilized to provide confirmation of predicted settlements. Permanent benchmarks and control monuments have been established at the site and used for survey reference points. Periodic evaluation checks of these benchmarks and control monuments will be made against the offsite control points. miO682-0120a100

24 REQUEST 1.13 Plans and details for permanently backfilling underpinning excavations including compaction specifications for granular fill under FIVP.

RESPONSE

The plans and details for the permanent backfill of the onderpinning excavation has been provided in the response to review concern No 2, Phase 4 provided in Enclosure 2 to Serial 17204 dated June 7, 1982. Existing Bechtel specification 7220-C-211 (Q), " Purchase of Structural Backfill", will provide the basis for the compaction requirements for the granular fill under the FIVP. i i i i i I i i l l i miO682-0120a100 l

25 P.EQUEST 1.14 Procedure to be required for detecting extent of planar openings uncovered in drift excavations and controls to minimize their effects.

RESPONSE

Our response to this request was contained in an enclosure to Serial 17225 dated May 14, 1982 and is summarized as follows: Review Concern 11 - Explain nominal area of allowable void without grouting and method of measurement, while tunneling under the turbine building. Response - A void should not exceed 8 feet beyond the access drift wall lagging line without evaluating the need to grout or use other remedial actions. The allowable void depth is based on the maximum distance the turbine building mat can safely span in one-way action. Therefore, the length of the void is not critical. The depth of the void is considered to be the maximum distance a 1/4" X 1" wooden rod can be placed into the void, without excessive force, with the rod placed approximately perpendicular to the access drift wall. miC682-0120a100

A 2-d- 26' '1 INFORMATIONAL RE', 'ST 2 Provide the following information regarding the Service Water Pump Structure: REQUEST 2.1 1 Acceptability of 1.5 FSAR SSE versus SSRS as bounding design.

RESPONSE

See response to Question 1.8 l 1 4 i i 1 i I i i i i 4 l l .i i i i 1 i i miO682-0120a100

'27 REQUEST 2.2 Slid'ing calculation using site-specific response spectra (SSRS) seismic loads and provide results with basis for assumed soil input parameters.

RESPONSE

The soil parameters used in the sliding calculations are based on the Woodward-Clyde borings of 1931. The following parameters were established for the glacial till: Angle of internal friction ($) = 36 Cohesive Force = 730 pcf The angle of internal friction, $ for the till material was established as 29* (refer to Question 41 of the Responses to NRC Requests regarding plant fill). The results of sliding calculations were provided in the response to in Serial 16656 dated April 23, 1982. That response is repeated below: Confirmatory Issue 6 - Perform sliding calculations using site-specific response spectra (SSRS) seismic loads and provide results. Response - The stability analysis calculations have been refined using seismic loads equal to 1.5 times the Midland FSAR safe shutdown earthquake (SSE) loads. these exceed the SSRS seismic loads. Factors of safety against sliding are now 1.45 in the north-south direction and 1.5 in the east-west direction. These values exceed the required value of 1.1. Hence, the foundation is acceptable. miO682-0120a100

e 28 REQUEST 2.3 Stress condition for existing parts of structure

(a) Maximum stresses (b) Critical combinations (c) Identify true critical elements based on actual rebar

RESPONSE

Our response to this request was contained in an enclosure to Serial 16656 i dated April 22, 1982. That response is repeated below: Confirmatory Issue 11 - Provide more information as to stress condition for i existing parts of structure: 4 i j Maximum stresses Critical combination Identify true critical elements based on actual rebar (To demonstrate the behavior of the structure, provide the above information for a loading combination which generally gives governing stresses for the structure.) i Response - The building has been analyzed for all the applicable loading combinations. The various structural components have been designed for the governing load combinations. It has been noted that the following load combination generally governs. i 2 U = 1.0 (D + F + L + H + S + Pg + E') miO682-0120a100

29 where 4 H - lateral earth pressure 1 i 1 4 S = surcharge 4 i E' = Midland FSAR SSE For each wall and slab in the structure, plots of the element forces due to static, preload, and seismic forces at a vertical and horizontal line of ~ elements were obtained to study the building behavior. A copy of the graphs for the south wall are attached as Figures SWPS-2 through 10. i I ( i i 1 i f f i i l i l miO682-0120a100 l i ,,n-.. ..nn .,. --, - -., - - --.... - -- - -,,., - -, - -, +

30 REQUEST 2.4 Calculation for determining lateral earth pressures under dynamic loading.

RESPONSE

The dynamic lateral soil pressures applied to the SWPS finite element model were calculated in accordance with the diagrams presented in FSAR Figure 2.5-45. The dynamic soil increment for each portion of the SWPS was calculated based on the actual soil depth acting on that particular portion of the building. For the north wall of the cantilevered portion of the SWPS, the dynamic increment was calculated based on a soil depth of 17 feet 0 inch (from El 617'-0" to 634'-0"). This is the same soil depth used to calculate the static pressure on this portion of the building. For the north wall of the lower portion of the SWPS, the dynamic increment was calculated based on a soil depth of 30 feet 0 inch (from el 587'-0" to 617'- 0"). In addition, the catilevered portion was assumed to be supported by the underpinning foundation and no surcharge was applied to the trapped soil area. Again, the soil depth used to calculate the dynamic increment was the same as that used to calculate the static earth pressure. During their structural audit of the service water pump structure (SWPS) held s March 16 through 19, 1982, NRC staff questioned why the dynamic soil increments for the north wall of the SWPS lower portion were not calculated based on the full soil depth from El 634'-0" to 587'-0". The following is a justification for the approach used in the design. The underpinning foundation was assumed to behave as a buried structure and had no dynamic soil increments applied to it. Because the wall is confined on miO682-0120a100

31 both sides by soil, a dynamic increase in soil pressure on one side is resisted by an increase in soil pressure on the other. Thus, the seismic wave, in effect, passes through. This pass-through effect is then dissipated by the trapped soil through friction. We believe the dynamic soil increments have been applied correctly; however, calculations have been performed to determine the effect on the structure of dynamic soil increments based on the full soil depth. These calculations indicate that for a north-south operating basis earthquake (OBE), the driving force on the SWPS due to the dynamic soil increments would increase by approximately 285 kips. The increase in stress due to the additional soil dynamic pressure is negligible compared to the stresses from the building inertial forces of approximately 4500 kips. With the increased forces, the factor of safety against sliding is still greater than the allowable. Calculations also indicate that an increase of this magnitude in the dynamic soil increments can safely be resisted by the walls for the effects' of transverse bending. The results of the investigation indicate that even applying the dynamic soil increment in the more conservative way, no adverse overall or local effects occur. I I l l l miO682-0120a100 ( l

32 REQUEST 2.5 Settlement monitoring program to be required during plant operation with action levels and remedial measures identified (Tech Sepc.) l

RESPONSE

1 l i 1 See response to Question 1.12 contained in this document. 1 i 1 I J i 4 i 4 4 i 1 I i i i } ~. i J i j l l i i l l 1 I miO682-0120a100 I i f

33 REQUEST 2.6 As-built report with confirmatory data on underpinning in-FSAR upon completion of construction.

RESPONSE

See response to Question 1.6 contained in this document. miO682-0120a100

34 REQUEST 2.7 Report on crack evaluation to include consideration of the effects of multiple cracks.

RESPONSE

See response to Question 1.2 contained in this document. miO682-0120a100

35 SUPPLEMENTAL INFORMATION REQUESTS TO SECTION 2.0 The following responses are applicable to the Service Water Pump Structure. SUPPLEMENTAL REQUEST 2.8 Provide the status on the interaction study between the Service Water Pump Structure and Circulating Water Pump Structure.

RESPONSE

The seismic displacement of the SWPS at the elevation of the CWIS roof slab is 1/4" for SSE. The CWIS concrete roof seismic deflection is expected to be of the same order of magnitude (calculations to verify this are being performed). The gap between the CWIS and the SWPS is 1". Hence there is an adequate gap between the two structures to prevent the hammering of the two structures during a seismic event. miO682-0120a100

36 SUPPLEMENTAL REQUEST 2.9 Provide an updated commitment on building monitoring during underpinning construction.

RESPONSE

Consumers Power Company will augment the strain monitoring program described in the enclosure to Serial 16656 dated April 22, 1982 as follows. Additional extensometers with an approximate 5 foot gage length will be located in critical areas. The location and acceptance criteria for these additional gages will be supplied at a later date. With this change Consumers will have a strain monitoring program which will support evaluations of the effect of singular and multiple cracking. Consumers is also aware of the NRC Staff's interest in utilizing the results of the settlement monitoring program. As the result of discussions with the NRC Staff, Consumers proposes the following: 1. A minimum of four deep seated benchmarks will be installed. 2. Consumers will use the data from the settlement monitoring program as a back-up to the data obtained from the strain monitoring program when evaluating the structure for the effects of underpinning construction. 3. Consumers and the NRC Staff agree to the use of a trigger value of 50 mils for the elastic differential settlement between the north and south walls of the underpinned position of the of the building. The effects or structure rotation are excluded from this value. miO682-0120a100

37 I!TFORMATION REQUEST 3 Provide the following information regarding the Borated Water Storage Tanks: REQUEST 3.1 i Adequacy of governing load combination used in design

RESPONSE

l Our response to this request was contained in an enclosure to Serial 14902 dated November 24, 1981. See Tables 1-6 and Figures 20 and 21 attached. Tables 1, 3 and 5 and Figure 20, give the forces from the governing load combinations and the capacities of the New Ring Beam, valve pit members, foundation footing and interface shear connection for the FSAR loading combinations supplemented by Q.15 " Responses to NRC questions regarding plant fill." Tables 2, 4 and 6 and Figure 21 give the corresponding figures for the same components of BWST foundation for the ACI 349 supplemented by Reg Guide 1.142 criteria. These tables and figures show that the new construction and the existing portions of the BWST foundation are adequate for both the Midland FSAR supplemented by Q 15 as well as ACI 349 supplemented by Reg Guide 1.142. j miO682-0120a100

l Mid1cnd Plcnt Unita 1 Cnd 2 Design 0; ports morcted Water i Storag2 Tcnk Foundaticn3 NRC REQUEST 3.1 j TABLE 1 i

SUMMARY

OF CALCUIATED I4 ADS AND CAPACITIES OF Tile NEW RING BEAM (MIDEAND CRITERIA) i l Axial and Flexural Interaction Asial, Shear, 'and Torsion Inte ract ion Calculated Load a n Calculated Loadin i Load Grid Axial Moment Load Crid Asial Shear Category Combination 888 Number Tension Moment Capacityl8*88 Combinationt'l Ntsaber Tension Shear Torsion 881 Capacitys t,4 p Region A 10 34 28 3 2,492 3,573 10 14 290 31 237 185 Region B 10 6 290 3,153 3,575 10 36 282 142 345 249 I -l Region C 10 5 285 3,547 6,492 10 37 278 135 394 553 l Region D 10 4 293 3,822 8,225 10 38 288 123 679 333 Region E 10 3 280 4,041 7,464 10 39 274 120 932 619 8'laefer to Section 5.0 of the Design Heport for the Borated Water Storage Tank Foundations for load combinations 48'Antal and shear are measured in kips moment and torsion are measured in ft-kips 88' Interaction capacities at calculated axial load til nteraction capacities at calculated asial load and torsion I isl ncluding torsion due to eccentricity of the interf ace shear force I lk 4 e l s uss l \\ / .m i" 2 l >s'- A - -. x

__ Midicnd Plcnt Unito 1 cnd 2 Dec1gn Reports Borcted Mtcr Stcrrg2 Tank Foundttiens URC REQUEST 3.1 TABLE 2 StMMARY OF CAlfULATED I4 ADS AND CAPACITIES OF THE NEW RING BEut ( ACI 349-76 LOAD COMBINATIONS AS SUPPLEMENTED BY REGULATORY GUIDE 1.142) Aslal and Flemural Interaction Asial, Shear, and 1braion Interaction Calculated toad 888 Calculated toad N 8 Load Grid Aslal Moment Load Grid Asial Shear Category Combinationt'l Number Tension Moment Capacityl8.38 Combinationt'8 Nuanber Tension Shear Torsionl83 Capacity (8edl Region A A 8 239 2,731 3,638 A 28 259 3 310 123 Region 8 A 6 226 3,494 3,660 A 36 309 153 439 156 Region C A 5 215 3,919 6,640 A 37 308 147 510 460 Region D A 4 211 4,316 8,458 A 38 323 130 855 193 Region E A 3 187 4,653 7,701 A 39 312 124 1,154 501

8. !!-

d 8'8Contro111ng ACI 349-76 load combination is: A. U = 1.4D + 1.4T + 1.4F + 1.7L + 1.7H + 1.9E g ease a ' ' ' trhere D = dead load a m at ' L = live load F = hydrostatic pressure from groundws. r T = differential settlement M = lateral earth pressure E = operating basis earthquake 888Antal and shear are in kips: soment and torsion are measured in it-kips isl nteraction capacities at calculated asial load I N j 8*' Interaction capacities at calculated asial load and torsion 888 Including torsion due to eccentricity of the interf ace shear force

== Midirnd Plcat Unito 1 Cnd 2 Design RIports Boretsd Wat3r Storags Tcnk Foundations NRC REQUEST 3.1 TABLE 3

SUMMARY

OF CALCULATED LOADS AND CAPACITIES OF THE VALVE PIT MEMBERS (MIDIAND CRITERIA) Axial and Flemural Interact ionia Shear Calculated Load In-Plane Transverse Axial Moment Category Combina t ionstil Calculated Capacity Calculated Capacity Tension Moment Capacitysas 180 903 1,570 Exterior walls 10 198 332 172 2,734 3,700 Interior wall 10 51 204 (ring wall) Roof slab *8 f N-8 directionUI NA 18.6 41.1 16.4 19.4 7.3 8.7 50.5 E-w directiontes gaten 18.6 60.3 4.9 19.9 0.1 3.7 33.0 Floor elab'd' N-S direction8 NA '8 28.6 45.8 15.7 23.4 16.7 20.6 27.5 l E-w directiontal 10 28.6 42.8 11.4 22.9 33.3 5.3 8.5 l'IRefer to Section 5.0 of the Design Report for the Borated Water Storage Tank Foundations for load combinations ta' Units are in kips and feet. 188 nteraction capacity at calculated axial load is-rima smaan I l*3 Forces shown are per linear foot of slab. ( % 88' Based on maximum of all load combinat' ions telDirection of the axial force nannt / X vammess suma m. N AstAL TWsted ' a.

Nidicnd Plant Units 1 and 2 Design Report: Borr.ted Watcr Stcrage Tank Foundations NRC REQlIEST 3.1 TABLE 4 SUlstARY OF CALCULATED IDADS AND CAPACITIES OF Tim VALVE PIT MEMBERS i ( ACI 349-76 IAAD COMBINATIONS AS SUPPLEMENTED BY REGUIA70RY GUIDE 1.142) Asial and Flesural Interactionsa: Shearts: calculated Load In-Plane Transverse Axial Homent Category Coebinations 'l calculated capacity calculated capacity Tension Moment capacityt88 t 192 1,411 1,570 Eaterior walls A 200 331 156 3,381 3,700 Interior wall A 71 206 (ring wall) 4 Roof slabl*l 883 NA 24.5 42.2 15.2 20.0 1.5 11.9 53.8 N-S direction E-W directioneel NA888 24.5 60.3 5.3 19.9 0 3.6 33.0 Floor slab 888 N-S direction A 34.4 45.8 15.2 23.0 16.6 26.2 27.8 3 E-W directiontes yges 34.4 42.9 13.7 23.0 32.7 7.6 9.4 l'icontrolling ACI 349-76 load combination is: A. U = 1.4D + 1.4T + 1.4F + 1.7L + 1.7H + 1.9E is-esm s samaa where ( 5 D = dead load L = live load l F = hydrostatic pressure from groundwater T = differential settlement ummer i H = lateral earth pressure l E = operating basis earthquake / 883 Units are in kips and feet. usa tuostas 88' Interaction capacity at calculated axial load s una tuostem o l*' Forces shown are per linear foot. to Based on maximum of all load combinations uut sua olrection of the axial force

Midland Plcnt Unito 1 cnd 2 Design R; port: BorOtCd Watsr Storage Tank Foundations NRC REQUEST 3.1 TABLE 5

SUMMARY

OF CALCULATED LOADS AND CAPACITIES OF THE FOUNDATION FOOTING (MIDIAND CRITERIA) Load Type of Load Combination ( S I Calculated Load (2) Capacity (2) Moment 7 3.0 37.5 Axial Tension 7 19.5 30.3 Shear 7 3.7 15.6 ( ) Refer to Section 5.0 of the Design Report for the Borated Water Storage Tank Foundations ( lunits are in kips and feet per linear foot of footing ll l s f l i p l s' s'O c 's l 't i l l i i i I /// ixm mim, yERENT SIZAR

Midicnd Plcnt Unita 1 cnd 2 DeOign Report: BorctCd Wat0r St0rtga Tcnk Foundctign3 IGC REQUEST 3.1 TABLE 6

SUMMARY

OF CALCULATED LOADS AND CAPACITIES OF THE FOUNDATION FOOTING (ACI 349-76 LOAD COMBINATIONS AS SUPPLEMENTED BY REGULATORY GUIDE 1.142) Load U8 Calculated Load (2) Capacityt2; Type of Load Combination Moment A 3.3 37.5 Axial Tension A 24.5 30.3 Shear A 4.1 14.8 Mi Contro' ling ACI 349-76 load combination is: i A. Ue 1.4D + 1.4T + 1.4F + 1.7L + 1.7H + 1.9E where D = dead load L = live load F = hydrostatic pressure from groundwater T = differential settlement H = lateral earth pressure E = operating basis earthquake j (2 Units are in kips and feet per linear foot of footing. i i '~ % ,s l / p FN g 't i I l i i e 1 l 1 e a / /// um..

I l / CAPACITY ENVELOPE j p- - - - g l l one e l 70.0 g g 1 i 1 I I I 5 80.0 j g j l i 1 1 I l l I a" 50.0 l g g y g E L----- J L o 40.0 l g n. U DESIGN FORCE ENVELOPE A 3o o MIDLAND LOAD COMBINATIONS ] / 8 / ^ i 1 20.0 g 7 4 g xe 10~0 Vv i i j 5 10 15 ,20 25 30 35 40 NRC REQUEST 3.1 O.0 C0llSUMERS POWER COMPAllY i MIDLA119 PLAIIT lill1TS 1 & 2 BWST FOUNDATION MAXIMUM DESIGN LOADS AND ? CAPACITIES OF INTERFACE SHEAR i CONNECTORS (MIDLAND CRITERIA) l FIGURE 20

nav etase 80.0 pCAPACITY ENVELOPE __q 70.0 l g I I 1 l I I I 60.0 j 3 l l I I Gi l l l l 1 I 6 '" l g L_______l _____a 40.0 8 30.0 DESIGN FORCE ENVELOPE u-FOR ACI 349 COMBINATIONS E 20.0 I \\ ^ 10.0 y gg NRC REQUEST 3.1 0.0 s i is 20 2s 30 as 4 CONSUMERS POWER COMPAllY MIDLAND PLANT UNITS 1 & 2 GRID LOCATION BORATED WATER STORAGE TANK MAXIMUM DESIGN LOADS AND CAPACITIES OF INTERFACE bHEAR CONNECTORS (ACI 349 CRITERIA) FIGURE 21

38 REQUEST 3.2 Acceptability of 1.5 FSAR SEE versus SSRS as bounding design.

RESPONSE

See response to Quertion 1.8 contained in this document. miO682-0120a100

39 REQUEST 3.3 Settlement monitoring program to be required during plant operation with action levels and remedial measures identified (Tech Spec).

RESPONSE

See response to Question 1.12 contained in this document. In addition to the above, the response to Confirmatory Issue 2 in our April 22, 1982 Serial 16656 provided details on strain monitoring and acceptance criteria. The strain provides a measure of the affects of settlement on the ring foundation. l l l l I miO682-0120a100

[ 40 PIQUEST 3.4 As-built report with confirmatory data in FSAR on completed construction.

RESPONSE

See responses to Question 1.6' contained in this document. 1 I I miO682-0120a100 i l t _., _. -. _... ~. _ _. _ _ _ _., _ -..,.... _ _. _ _.....,,. _. - _, _ _ _ _ _. _ _, _. _ _ -,. _ _.. _ _.,,. -., _.., _... _....... _.. _ _...,.

o 41 INFORMATIONAL REQUEST 4 Provide the following information regarding underground pipes: REQUEST 4.1 Basis for modeling of the piping inside the building in the terminal end analyses.

RESPONSE

The piping is modeled inside the building to a point which is considered a terminal end or anchor. The anchor point is defined by the pipe analyst as a point where the motion of the piping is completely fixed in all directions. i l miO682-0120a100

---

,n--

- - - -~ ---- - - - -

• w~r

42 REQUEST 4.2 Controls to be required during plant operation to prevent placement of heavy loads over buried piping and conduits.

RESPONSE

We have performed an aaalysis which envelopes any anticipated construction or operational load during the life of the plant. It indicates that at the buried depths of the safecy grade utilities overburden due to heavy loads will not affect the pipe. The stresses calculated from the enveloping load are still below yield point of the piping. This information was provided in our December 15, 1981 submittal and discussed in detail during our NRC staff meetings held in January and February. To prevent soil settlement that could be detrimental to the buried piping and conduits because of heavy laydown loads or other heavy loads, we will designate exclusion zones in the yard areas where buried safety grade utilities exist. The exclusion zones will be designated on the yard piping drawings along with maximum allowable loads and laydown times for these exclusion areas, which will be incorporated in the technical specifications. The control procedure will be handled in conjunction with the procedures for controlling heavy loads inside the plant according to NUREG 0612. miO682-0120a100

43 REQUEST 4.3 As-built report with confirmatory data in FSAR on completed construction.

RESPONSE

We have agreed at the April 16, 1982 meeting with the staff and in the April 15, 1982 letter, Serial 16638, to provide this as-built and confirmatory data to the NRC staff. This information will be supplied separately within 6 months of completion of construction and referenced in the FSAR. l miO682-0120a100 i l

44 REQbEST 4.4 Justification why the BWST lines are not to be rebedded from the tank farm dike to the auxiliary building.

RESPONSE

The measured profile data taken in 1979 indicates the maximum deflections measured to be within the construction tolerances for the installation of the pipe, 2 inches. Line 18-2HCB-1 from BWST tank 2T-60 had a maximum measured deflection of 1.92 inches and line 18-1HCB-2 from BWST tank 1T-60 had a maximum measured deflection of 0.96 inches. Lines 18-2HCB-2 and 18-1HCB-1 leading from BWST tanks 2T-60 and IT-60 respectively were not profiled because they were in the same pipe trench as those lines which were profiled. These lines should have similar elevation profiles because all the other 1981 profile data on buried pipes in same construction trench have similar profiles. Lines 18-2HCB-1 and 18-2HCB-2 from BWST 2T-60 have approximately 47 feet of pipe not rebedded and lines 18-1HCB-2 and 18-1HCB-2 from BWST IT-60 have approximately 20 feet of pipe not rebedded. The original design analysis of this pipe is still valid because it envelopes the construction tolerances for installation. The highest calculated stress for these lines in a faulted condition is 1477 psi with an allowoole of 45024 psi. The soils supporting the pipelines are either granular backfill or well compacted clay. The soils tests performed in the area of the BWST dike and the auxiliary building do not indicate sof t clay layers that would give long 1 term consolidation beneath these lines. The borings used to evaluate the i j miO682-0120a100

45 soils are: T-9, T-10, SWL-8 a,.d SWL-8A. These borings are referenced in the FSAR Section 2.5. miO682-0120a100

o 46 REQUEST 4.5 A list of all penetrations for underground seismic Category I piping. Revise and submit your pipe monitoring program to include periodic measurements of rattlespace for plant operating life. Provide justification for all exceptions.

RESPONSE

The penetrations for all the Seismic Category I piping to be monitored are shown on Drawing SK-C-745, Figure 7, in our March 16, 1982 submittal Serial 16269. The Category I classification on Line 48-0HBC-2 has been changed to its functional separation at the butterfly valve inside the building. We are committing in this response to monitor the penetration rattlespace for all the seismic Category I penetrations with piping which has not been rebedded. The penetrations to be monitered at the auxiliary building are associated with the following piping: 18-1HCB-1, 18-1HCB-2, 18-2HCB-1, 18-2HCB-2, 26-0HBC-19, 26-0HBC-20, 26-0HBC-15, 26-OHBC-16. At the Diesel Generator Building the following penetrations will be monitored: 8-1HBC-311, 8-1HBC-310, 8-2HBC-81, 8-HBC-82. The monitoring frequency for the penetrations will be yearly for the first five years of plant operations. Technical specifications for the penetrations will be amended to FSAR Chapter 16 with the other comitted technical specifications concerning pipe monitoring on the Midland Site. l l miO682-0120a100

47 REQUEST 4.7 (sic 4.6) Justification for the high (beyond limits) reported settlement stresses.

RESPONSE

The corrected Enclosure (2) submitted in our April 15, 1982 letter, Serial 16638, identifies by footnote the high stresses which are fictitious due to end condition affects on the piping model. This enclosure does not have any j stress allowable limit associated with it due to the unconventional load combination requested. i i I a i i k miO682-0120a100

48 INFORMATIONAL REQUEST 5 Provide the following information regarding the Diesel Generator Building: REQUEST 5.1 A structural reanalysis considering: (a) Presurcharge conditions (b) Conditions during the surcharge (c) 40-year settlement effects (d) The combined effects of (a) through (c) above

RESPONSE

Our response to this request was contained in an enclosure to Serial 17228 dated June 1, 1982. miO682-0120a100 .J

49 REQUEST 5.2 A structual reanalysis assuming reduction in soil spring stiffnesses between bays 3 and 4 on the south side and beneath adjacent cross wall.

RESPONSE

Our response to this request was contained in an enclosure to Serial 17228 dated June 1, 1982. I i i miO682-0120a100 1 - -. _ -, _ _ _ _ - _ _ _ _ _ _ _ _ _ _ _ _ _ _., _ _ _ _.. _. _ _ _ _ _. _. _.. _ _,, ~ _. - _

50 REQUEST 5.3 A statistical evaluation of settlements to evaluate impact of survey inaccuracies versus actual differnetial settlements which have been experienced.

RESPONSE

Our response to this request was contained in an enclosure to Serial 17228 dated June 1, 1982. miO682-0120a100

51 REQUEST 5.4 Acceptability of 1.5 X SSE (FSAR) versus SSRS for bounding design.

RESPONSE

The design basis of the Diesel Generator Building is the FSAR SSE. An evaluation of this building for the SSRS loading will be performed in the seismic margin review which is presently being performed. The results of this margin review will be provided along with the results of the other plant structures, equipments and components when completed. miO682-0120a100

52 REQUEST 5.5 Criteria relating crack width and spacing to reinforcing steel stress.

RESPONSE

See response to Question 1.2 contained in this document. The Diesel Generator Building has been evaluated for all existing cracks, and found to be acceptable to carry all the applicable loads. The results of this evaluation have been submitted as indicated in response to Question 1.2. Since no remedial work is planned for the Diesel Generator Building, no criteria for crack width and spacing is required. miO682-0120a100

53 REQUEST 5.6 Settlement monitoring program to be required during plant operation with action levels and remedial measures identified (Tech Spec).

RESPONSE

See response to Question 1.12 contained in this document. 4 miO682-0120a100

54 REQUEST 5.7 Evaluation of effect of past and future differential settlements to diesel lines from the day tank to the diesels.

RESPONSE

The stress effect due to settlement on the piping connecting the diesel fuel oil day tanks with the diesels is negligible fer several reasons. The piping was installed (connected) after the surcharge period and therefore, the piping has no induced stress due to past differential settlement between the diesel pedestal and building. The pipe sizes connecting the tank and diesel are all two inches or less in diameter and very flexible in nature. The future predicted differential settlement between the day tank and diesel pedestals is conservatively estimated to be less than 3/4 of an inch. The resulting stress will be less than the 18 ksi calculated for a 3-inch future settlement calculation on buried fuel oil lines submitted in our December 15, 1981 submittal which is within the allowable 45 ksi for the piping. miO682-0120a100

55 INFORMATIONAL REQUEST 6 Provide a settlement monitoring program to be required during plant operation with action levels and remedial measures identified (tech spec) for the underground diesel fuel oil storage tanks.

RESPONSE

The settlements for these tanks will be monitored and evaluated during operation as committed in Sections 2.5.4.13.2(c) and (d) of the Midland FSAR and will be included in the technical specifications as stated in response to Item 1.12. We have showed that the diesel fuel oil storage tanks are stable and that both the past and future settlements are insignificant (0.2" and 1.25", respectively). This information was submitted in our prepared hearing testimony and the staff agreed with our conclusion in their prepared hearing testimony. Our May 31, 1982 submittal, Serial 16881, has an Enclosure 2 which addresses the liquefaction potential of the soil under the diesel fuel tanks and concludes that there is adequate resistance to tank floatation if soil liquefaction occurred during a seismic evenc. miO682-0120a100

56 INFORMATIONAL REQUEST 7 Provide the following information regarding the permanent dewatering system: REQUEST 7.1 Results of the dewatering recharge test.

RESPONSE

Our response to this request was contained in an enclosure to Serial 17304 dated June 7, 1982. Refer to the report on the permanent dewatering system recharge time verification test which is updated as follows: Introduction As a result of the site-wide exploration program, zones of potentially lifquefiable saturated granular backfill materials were discovered supporting some Seimic Category I structures and buried utilities. Remedial measures, which also eliminate the potential for liquefaction, are planned for all but two locations. At the Auxiliary Building Railroad Bay and Diesel Generator Building areas there will continue to be a potential for lifquefaction, during the SSE, in saturated backfill sands existing above el 610'. To eliminate this liquefaction potential, a permanent plant dewatering system was designed to prevent ground water levels below el 610' for these two areas. During operation it is planned to maintain the groundwater level at about elevation 595' To determine the reliability of the permanent dewatering system, analysis of data from pumping tests and groundwater level responses to changes in cooling pond levels was performed to evaluate the of groundwater responses indicated miO682-0120a100

57 that there would be sufficient time for maintenance, repair or replacement of the system before groundwater levels reach el 610' at the two critical areas. To satisfy the NRC staff about the validity of the mathematical model, a full scale recharge test was performed to determine the actual recharge time at the critical areas. Scope The full scale test was performed between November 20 and April 2,1982. The test consisted of two phases: drawdown and recharge. Drawdown Phase The drawdown phase of the test commenced November 20 and involved pumping from the 20 permanent backup dewatering wells, selected individual observation wells equipped with self-contained eductors, existing construction dewatering wells, and temporary dewatering wells (Figure 2). The ground water levels around the site were lowered to el 595' or as low as practical, with the cooling pond at el 627'. Groundwater level readings were taken twice a week to monito: drawdown rates. The water level readings at the conclusion of the drawdown piase of the test were taken under an approved quality assurance p rogram. Figure 3 shows groundwater levels at the conclusion of the drawdown phase. Recharge phase The recharge phase of the test was initiated on February 4,1982. All pumping l at the site was discontinued on this date. Ground water levels around the site were measured twice a week. All measurements were performed under an approved quality assurance program. Locations and hydrographs of observation miO682-0120a100

58 wells at the two areas are shown on Figures 4 and 5, respectively. The recharge phase of the test was conducted for a period of 60 days. The response of observation wells in the Diesel Generator Building area are representative of the recharge rate from the cooling pond in the event of a complete well shutdown. In the Auxiliary Building Railroad Bay area a high pressure construction water line was broken between March 11 and March 17, 1982 which resulted in flooding of the railroad bay floor including observation well AX-2. Therefore, the water level indicated in AX-2 on March 15, 1982 does not represent a saturated water level within the backfill. As con be seen on Figure 5, the water level began dropping prior to the water line being shutoff. Observed water level readings for ooservation wells AX-13A, CA-9A and T-21A also may have been influenced by the broken water line. Nevertheless, there is still considerably more than 60 days recharge time available at the Auxiliary Building Railroad Bay areas, even after complete well shutdown. Conclusions Evaluation of the data from the full scale recharge test indicates the following: A permanent dewatering system can lower ground water levels to I approximately el 595.0' at the two critical areas. A minimum of 60 days is available for maintenance, repair, or replacement of the system before ground water levles at the two critical areas exceed i el 610' prior to the SSE. i miO682-0120a100 l l

e 59 REQUEST 7.2 Technical specification requirements on the permanent dewatering system.

RESPONSE

Our response to this request was contained in an enclosure to Serial 16629 dated April 19, 1982. Section 8.0 technical specifications of that submittal is updated as follows: After the plant operator has verified that a watar level measurement higher than El 595' is a correct reading and the repair measures given in Table V-1 do not affect the rise in groundwater level at the DGB or auxiliary building railroad bay areas, the plant will be shut down when any observation well at either critical area exceeds el 607' (see Figure V-1). A technical specification will be prepared detailing the coordination of the shutdown. miO682-0120a100

Summary of Soils-Related Issues at the Midland Nuclear Plant NRC REQUEST 7.2 TABLE V-1 WELL FAILURE MECHANISMS AND RESPONSES 50.54(f) Event Reference Repair Time 1. Electrical Failure a. Single well (wired 24.a, Less than 1 day. in parallel) 24.c, 47.1.b b. Multiple wells due 24.a, 1 day to initiate operation to power outage 24.c, of backup diesel power to 47.1.b interceptor wells. Operate until normal power can be restored. Backup interceptor wells automa-tically begin pumping if water levels exceed el 595'. 2. Failure of timers / 24.c, Less than 1 day; replace-pumps / check valves 47.1.b, ment parts onsite. 47.6 3. Header pipe break 24.c 1 day to attach flexible hose to each well affected and pump water to storm drains. In case of inter-ceptor well header failure, initiate backup wells (on separate header system). 4. Well screen encrusta-24.h, 2 days to acidize well. tion 47.6, 47.8 5. Complete loss of well 24.c, 4 days to replace one well 47.1.b using cable tool rig. 1 day if other drilling method used. If well or wells need to be replaced, there is enough redun-dancy and pumping capacity to prevent water levels from rising in plant fill, while the replacement wells are being installed.

NRC REQUEST 7.2 I I l COMBINATION SHOP j 54400 EVAPORATOR BUILDING COOLING TOWER O o' g o OILY WASTE Q STORAGE & " ' ^ '"' .= g TAlWC FARbt ANEA '[ ./ HYDROGEN - - I *- RA0 WASTE BUILDING AUXILIARY O I BUILDING s4.= \\ /& a T I } UNIT 2 UNIT 1 i CONTAINlMI CONTAINM o ADMIN. AND SERWCE BUWG TURBINE BUILDING 55&as e a SERVICE WATERh = s" cma' alica R11,, niscala m a, mismTor a Prig SMILDeleG ?- CIRCUL. $0uE @~ s 2.-

• 1. s'u"C u'RE

'" ^*' 9 CONDENSATE D COOLING POND STO R AG E < C* TANKS c-c DIESEL GENERATOR FUEL OIL STOR AGE TANKS ~ ^ 4 Il ill ! 111111111 tillililtTN ss4 O A \\ 5 a ~ CONSUMERS POWER COMPANY ~ ~^" ~ MIDLAND UNITS 1 AND 2 AREAS COMurTTED TO PERMANENT DEWATERING AREAS COMMITTED TO ,so PERMANENT DEWATERING sc,u,N,EET FIGURE V-1 G 1986-22

60 REQUEST 7.3 A summary dicussion of your contingency plans which would be implemented in the event ground water levels at critical locations exceed limits in the technical specifications.

RESPONSE

The critical groundwater level to preclude liquefaction in the area of the Diesel Generator Building and Auxiliary Building Railroad Bay areas' has been conservatively established at el 610'. It also nust be noted that liquefaction can only occur during a seismic event. Our contingency plans are being developed such that the plant would be in safe shutdown prior to the groundwater level reaching el 610' in critical areas and that appropriate measures would be taken to ensure that the groundwater level is maintained at or below 610' as required after safe shutdown. Steps that would be taken as the groundwater level rise is identified in critical areas is summarized as follows: 1. The permanent observation well, piezometer, on monitoring well indicating a groundwater level higher than el 595' will immediately be remeasured to verify that operator error or equipment malfunction has not occurred. 2. The permanent observation wells, piezometer, or monitoring well in the vicinity of the high reading will be manually measured. 3. If a rise in groungwater levels is verified, regardless of the cause, location, and extent of groundwater level rise, the pumping rate of the dewatering system will be increased. This can be accomplished either by miO682-0120a100

~ o 61 increasing the pumping rate of the individual wells, initiating the backup interceptor wells and/or standby area wells, installing pumps in the six monitoring wells, or all of the above. 4. The nearest dewatering wells will be examined for a dewatering yatem malfunction (pump failure, power outage, header pipe leak or fallure, high level switch or timer failure, etc). Flow rates will be checked. Appropiate repairs will be made. 5. An investigation will be conducted to determine if failure of any piping has occurred and the piping system -losed as required. s \\ 6. Should_any disruption occur in the electrical power supply, standby diesel generators will be available to supply power to the primary interceptor wells and backup well pumps on a temporary basis until the normal power supply is restored. The twenty primary interceptor wells are activated automatically and the backup wells can be activated manually. 7. The wells can be repaired or replaced to stabilize and/or reverse groundwater level rise. A complete set of replacement parts will be stored on site for any repair, replacement, or new installation which may be required. 8. As soon as a major pipe leak or other unsupected groundwater recharge is detected in either of the two critical areas, the following actions will be initiated: a. The recharge source will be identified and stopped or curtailed as soon as possible miO682-0120a100

O 62 b. Concurrently, an evaluation will be make to determine shether the area wells are sufficient to stabilize and maintain water levles below el 610'. c. The rate of groundwater level rise will be projected based on area well operation only. A critical water level will be determined for which safe shut down would have to be initiated to have the plant in cool shutdown prior to the water level reaching el 610'. d. Additional pumping capacity that might be required to stabilize and maintain groundwater levels below el 610' will be determined and steps taken for necessary emergency installation and operation. e. Safe shutdown will be initiated when the water level reaches the critical level determined in step c, regardless of status of new well installation. 9. In the event of a complete well systems failure and recharge occuring from the cooling pond, safe shutdown will be initiated when the water level reaches el 607' Steps 2 through 7 will be implemented as required to maintain the water level in critical areas below el 610', as long as required. Connection to the backup wells, or installation of pumps in the permanent monitoring wells can be accomplished within a 24-hour period. The above measures are considered more than adequate to ensure that groundwater levels stay below el 610' near the critical areas. The administrative procedures for accomplishing these measures will be included in a technical specification. miO682-0120a100

3.e 63 INFORMATIONAL REQUEST 8 Provide a settlement monitoring program to be required for structures founded on natural soils and plant fill which have not been identified above with action levels and remedial measures identified. (Tech Spec)

RESPONSE

See response to Question 1.12 contained in this document. miO682-0120a100 .}}