ML20055A967

Forwards Four Corps of Engineers Memos Re Underpinning of Auxiliary Bldg,Settlement Analysis of Diesel Generator Bldg & Dewatering Sys Recharge Time Verification Test Pertaining to Review of Applicant Submissions

ML20055A967
Person / Time
Site:	Midland
Issue date:	07/15/1982
From:	Mcallister P ARMY, DEPT. OF, CORPS OF ENGINEERS
To:	Lear G Office of Nuclear Reactor Regulation
References
NUDOCS 8207200192
Download: ML20055A967 (7)

Text

DEPARTMENT OF THE ARMY DETROtf DISTheCT, CORPS OF ENGINEERS DETROIT HI N 44231 "N % 15 JUL 1982 NCEED-T

SUBJECT:

Four Memoranda Providing Reviews of Applicant's Submissions Regarding the Midland Nuclear Power Plant.

Mr. George Lear U.S. Nuclear Regulatory Commission

, Ch, Hydrologic & Geotech. Engrg Br.

Division of Engineering Mail Stop P-214 Washington, DC 20555

Dear Mr. Lear:

Attached are four memoranda providing Corps of Engineers comments regarding the Applicant's submissions concerning the Midland Nuclear Power Plant. These submissions are summarized below:

Submission Date Topic 14 May 82 Underpinning ofhe Auxiliary Bldg.

1 Jun 82 Settlement analysis of the D.G. Eldg.

7 Jun 82 Dewatering System Recharge Time Verification Test 7 Jun 82 Underpinning of the Auxiliary Bldg.

Sincerely, 4 Inc1 P. LISTER, P.E.

As stated Ch'i , Engineering Division C o09 020'/200192 8207iS PDR ADOCK 05000 A

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15 JUL 1982 f.'C ELL-r SULJECT: Tour Namoranda Providing Acvieve cf Applicant's Subuissions Ee;;arding the nidlend huelcar Fover Plant.

i Fr. Coor;c Lear U.a. Luclear hogulatory Coaniesion Ch. tiyd rolettic & Geotech. Engrg Lt.

.tivision of Engineering

!> ail stop P-214 unshington, DC 20555 Ivar I;r. Laart Attached tre four sonoranda providing Corps of En41acers coccer.La regarding the APr11 cant's cubntantons concerning the Mid1snd liuclear Power Plant. 7tese submissions are ensuarited celous f Suprilaston Late Topic 14 1:ay S2 Underpinning ofkhe Auxiliary Elda.

l 1 Jun 32 Outtlenent aanlysis of the D.C. Eldg.

/ Jun 82 Levatoring systen Eccharge Time Verificction Test 7 Jun 82 Underpinnisu of the Auxiliary Lldy.

Cincerely,

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4 Incl P. Mc t.s stated Chic [,Git' .ILTur., P.S.

P.nginecting Division

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. . a SUBJECT-Midland Nuclear Power Plant - Review of the Applic_ ant's Submission of 14 May. 1982, pertaining-to the Underp, inning of the Auxiliary Buiiding.

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1. (Review concern 4). The sketches (sk- 785 and sk- 786)' furnished by the Applicant are not legible. Therefore, it is not possible to review the effectiveness of the construction dewatering wells.

However, from Table-1, it is clear that most of the wells end above the proposed foundation elevation of the underpinning walls '

of the Control Tower (Ed,*562) and the Electrical Penetration Area'(Ed=571). Thus these wells will not'be able to pump if waterisencounterfintheneighborhoodofthefoundationelevation. +

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2. (Review concern-ll) . The criteria to measure-the depth of voids by k"x1" wooden (red 71s not justified. A separation of'1/16" or even less is needed to releive the foundation soil from the building load,therefore,use[sYeelplatewillbemorerealistic.

3. (Review concern-13): This change in design for the access shaft components w$$e not known to the Corps-of Engineer's. It will be helpful, if the revised pressure distribution. diagrams are furnished t to complete the review. The excavation behind the access shaft as shown in Attachment-6 might be filled with : water th7 s creating considerable more pressure than normal earth pressure.

4. (Review concern-4). The explanation given by,the' Applicant as to the design of the initial access shaft:.is not clear. Removing the soil support from under the structure to relieve the surcharge load might be detrimental to the structure.

Hnbany,-

H.N. SINGH, P.E.

Lead Reviewer - 1 Midland Plant f

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SUBJECT:

Midland Nuclear Power. Plant-Review of the Applicant's Submission of June 1,1982 (Response to the NRC staff request for settlement related analysis for the Diesel Generator Building)

1. (page 6, last para)

According to Fig. 27-10, 10CFR 50.54 (f), the Diesel Generator Building walls were completed to elevation 654 by the end of March, 1978 therefore, ' case a' analysis must include the rigidity of the structure up to elevation 654.00. The analysis performed representing a grade bean) uptoheight635isnotrepresentativeo([Yctualcondition.

2. (page 7, para 1, and Fig 1-3)

Estimate of settlement for case b is not clear. Provide backup materials to evaluate the settlement.

3. (page 7, para 1, Figure 1-3)

The settlement values forg urcharge period (1/79-8/79) provided in Figure 1-3 are not consistent with those provided in Figure 27-11, 10CFR, 50.54 (f) submission. Please clarify the discrepancies.

4. (page 7, para 1)

The Applicap ' -tatemppent "The comparison shows good correlation Between values resul' m the finite element model and the measured My%ues, and also for predicted settlement values" is not correct. Viewing the considerable rigidity of the structure' the dis repadcies between the measured settlements and the settlements obtained from the finite element solutions as shown in Figures 1-3A, 1-3B and 1-3C are alarming.

5. (page 7, para 1) ,

The measurement of settlements has already shown that the building has undergone rigid body settlement as well as settlements creating curvature.

It is not understood, why the Applicant keepsrestating that the building will undergo mainly rigid body motion. We understand that because of the high rigidity of the structure, the magnitude of the differentical settlement will be small in comparison to those of the rigid body settlement, but these mall

,difterential settlements would create very high stresses probably i ange of unacceptable leveh. ".

. 6. (~p age 7, para 2, last sentence; Attachment Ih2)

A comparison of isometric representatibn of Dr.fiffifi's 40 years settlement values given in Figure 2 of attachement I-2 with that shown in Figure 1-3B indicates that values of Fig. 2 (attachment'I-2) compare more closely to the measured values than those given in Fig. 1-33.. However, significant discrepancies still exist, and it appears reasonable to increase the lengths over which the spring values in Dr. Affifi's analysis are varied to achieve a settlement pattern comparable to the measured .vdiues. This analysis is expected to indicate further increase in the steel, stresses in certain areas particularly in the footingst The Applicant should also kwou combined these stresses with other load combinations to verify the adequacy of

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structural members. It appears that stresses in the footing shown in Table 1 CAttachment I-2) when combined with the stresses due to tornado will reach theygfldvalueofthesteel.

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7. (page 1 thru 8)

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The Applicant's s ttlement data anaysis does< r.ot ,arove thet the structure has not undergone dif ferential settleme ;t. In r'pffengineeriag

• activity involving measuraments, some human errors are inu 1ved. This 'd aes not invalidate the tesd1ks provided the work. h'as 'not been[ carried indo,,

unprofessional 'minner. 'If'the Applicant has concluderV that' all of if(5.

previous measurements are incotreet, ctual information pertaining to. the settlement thenofit does the D.C. not;E.

nave1any do n>8t believe the Corps of Engineers will be able to concur wich the dita wr.~ich have -

been modified to suit the situ'ation favorable to the applicant.

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SUBfECT - Midland Nuclear Power Plant - Review of Applicant's submission I of 7 June 1982, on Permanent Dewatering System Recharge Time Verification Test.

The Corps of Engineers t.as reviewed the Subject Submission, and the 7

follawing comments are offered:

1. (Section 3 Enclosure-1, page 1)

Drawdown phase before start of the recharge test should be identical to that which would prevail during the normal permanent dewatering period.

j However, from Section 3, it appears that groundwater levels around the pite were lowered as low as practical with the cooling pond at Elevation 627.

Howevet, for the recharge time to be realistic, the groundwater at the site I should be as- high as possible consistent with 595.00 at the location where l liquifaction potential exists. i

2. (Section 4, para 2, page 2) I The statement made by the Applicant in the last sentence af paragraph l

, 2 is not justified. Recharge test results for wells T-21A, CH-9A, and l AX-13A appear to have started af ter 19 March and discontinued on 5 April or l earlier, therefore, the tests were not continued long enough to justify 60 l days recharge period

-Further,thkwaterlevelinthesewellswaslowered considerally below the elevation 595.00; Thus it is natural that it will takeflongerperiodoftimetoreachelevation610.00thanitwouldtakeif

, the recharge were started from the elevation 595.00.

b H.N. SINGH, P.E.

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SUBJECT:

Midland Nuclear Power Plant - Review of the Applicant's Submission of 7 June, 1982 (Response to staff concerns for Underpinning of the Auxiliary Building)

(1) (page 2-6, section 6.3)

In Figure 2-6, in the area of the Main Auxiliary Building two values for Modulus of Subgrade Reaction have been shown, it is not known which value of these values has been used in the analysis.

(2) (page 2-7, section 7.1.1)

The validity of the two models stated to be used to analyse the existing stresses has not been demonstrated.

(3) (page 2-7, section 7.1.2, para 2)

Has the analysis stated to be petformed according to paragraph 1 of this section considered the eifect of the jacking load at the end of the EPA as stated in this paragraph? If not,what is the purpose of making this statement at this stage?

(4) (page 2-7, 2-8, section 7.1)

How are the stage construction sequences and the phase construction sequences related? Without relating the two sequences it is not possible to review this aspect of the analysis.

(5) The bottom elevations of the underpinning walls for the Control Tower shown in Figures 2-1 and 2-2 are not consistent. In Figure 2-1, it is shown as 556.00, whereas in Figures 2-2, it appears to be 662.00.

(6) The values of stresses for two conditions (after soil removed and with jacking load) for the three stages of the construction provided in Table 2-4 need more explanation. We understand that soil will be removed after transfering the load on jacks except for the 30' length at the end of the EPA's during stage-I construction. It is not understandable how the structure will remain stable wi 5.out jacking and the structure could be analysed with soil removed.

(7) (page 2-8, section 7.2)

Where are the results of the analysis made to satisfy the staff concern 2b?

(8) (response to Review concern 6)

Please explain, how the loading and reloading curves obtained from the test will be utilized to determine the Modulus of Elasticity of the soil. I understand that, since the soil is not disturbed, the first loading curve will be used to determine the soil modulus.

(9) (page 6-4, para 1)

As confirmed by the borings, there is no appriciable variation in soils conditions in natural soil in the neighborhood of the proposed foundation elevation of the underpinning walls; the results of the plate-load test can be extended, without appreciable error to verify the settlement conditions of the piers and the walls which have foundation dimensions considerably larger than the plates to be used in the plate load tests.

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H.N. SINGH, P.E.

Lead Reviewer mM0WidUEilens