ML20082T157
| ML20082T157 | |
| Person / Time | |
|---|---|
| Site: | Midland |
| Issue date: | 12/06/1983 |
| From: | Mooney J CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | Harrison J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| CSC-7063, NUDOCS 8312150187 | |
| Download: ML20082T157 (2) | |
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CORSum813 POW 8f m e-w Executin Mmeager Midland Pmject Office oeneral offlete:' 1946 West Pernell Road, Jackson, MI 49201 * (517) 788-0774 PRINCIPAL STAFF V RA
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U S Nuclear Regulatory Commission Region III 799 Roosevelt Road-Glen Ellyn, IL 60137 MIDLAND ENERGY CENTER GWO 7020 CONCURRENCE FOR ADDITIONAL JACKING LGADS FOR THE EAST /8 GRILLAGE File:- 0485.16 UFI:
42*05*22*04 Serial: CSC-7063
.12*32 In'the above referenced letter, it was clarified that 160% of the specified load is planned to be jacked, in 5% increments (over the locked off load) into
- grillage 8 (EPA jacks) prior to completing the excavation for grillage 5.
The letter also stated that ~ the~ load in grillage '(EPA Jacks) will be reduced to
-the specified load-(800 tons) as-the load at grillage at 2 is applied.
L At the time of the letter, the jacking load in grillage 8 (EPA jacks) had been locked off at 125% of specified load.
(Percentages expressed hereafter are percentages of_specified load.)
In a September 29, 1983 telecon, Dr. R.
Landsman informed'CPCo not to institute additional reserve capacity load above 125% without NRC concurrence.
On November 15, 1983, CPCo indicated in a conference call with the NRC (Dr.
Landsman, J. Kane and others) that it would be necessary to increase the jacking loads for east 8 grillage to maintain the building elevation. East and West 8 grillage jacking and building elevation history was discussed.
It
.was mentioned that with the NRC restriction on jacking additional reserve capacity load, frequent rejacking of the grillages may be necessary to comply with the design specification.
It was explained that in one instance of rejacking of east 8 grillage, the lif t-off loads experienced were 131.3% for
~
. the X jacks,133.5% for.the Y jacks and 145.4% for the Z jacks.
(The X jacks support the Turbine Building, and the Y and Z jacks support the EPA.)
In a November 28, 1983 conference call with the NRC (Dr. Landsman and
-J. Kane), CPCo again requested permission to incresse the jacking lock off
. loads for the east 8 grillage.
Mr. Could of Mergentime explained that the previously agreed limitation on lock off loads (X=110%, Y=125%, Z=125%) is
(
hindering our ability to maintain the Auxiliary Building elevation.
l Specifically, the east 8 grillage had been recently rejacked twice over the
. Thanksgiving Holiday with the overall effect of losing building elevation, j$
u 8312150187 831206 OC1283-0000A-CN01.
PDR ADOCK 05000329
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Mr. Gould indicated that the current adjusted jack loads for the east 8 grillage were X=ll5%, Y=141.7% and Z=149%.
Mr. Could indicated that the frequent rejacking on the east side may be due to smaller than necessary lock off loads. The triggering mechanism for the rejacking is related to the structure reaching a downward movement of 0.010 inch in a 48 hour5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> period, as specified in the construction procedure.
CPCo recommended the following actions:
1.
Maintain current jack loads (X=ll5%, Y=141.7%, Z=149%) for the east 8 grillage / pier until the acceptance criteria of 10 mils in 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> is satisfied.
2.
After the acceptance criteria is met, reduce the E8 grillage / pier loads to X=ll5%, Y=135%, Z=135% and then lock of f X, Y and Z jacks.
Mr. Kane and Dr. Landsman indicated they concurred with the recommended actions.
This letter serves as documentation for the agreement on the recom-mended action.
It was also indicated by Mr. Kane that he would like to resolve the issue in total through the following steps:
1.
CPCo will complete its' evaluation of crack mapping and other mata to determine the effects of jacking loads on the Auxiliary Building.
Upon completion of this evaluation, CPCo will provide in writing, the conc-lusions of the effects of higher jacking loads on the Auxiliary Building to the NRC by December 9, 1983.
2.
A meeting is tentatively scheduled for the week of December 19, 1983 (later changed to January 4, 1984 through January 6, 1984), to completely resolve the outstanding issues relative to increasing jacking loads.
Discussions will include data and other information required to resolve the matter of jacking loads.
Although p?rmission has been received to increase lock off loads for the East 8 grillage as outlined above, it should be recognized that the increased jacking loads presently authorized may not necessarily be sufficient to maintain the building elevation.
If the jacking loads are not deemed suf-ficient due co unanticipated conditions, we may be requesting your concurrence for higher jacking loads.
(It should be pointed out here that the grillage at 8 including pier and foundation capacity has been dessgned for 2000T load which provides for any unanticipated conditions.) We thank you for your cooperation on this matter.
In l/1YlflCuesL
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JAM /RMW/k1w 1
OC1283-0000A-CN01