ML20031F563

Concurs W/Util Plans to Commence Surcharging of Borated Water Storage Tank Subj to Two Listed Conditions

ML20031F563
Person / Time
Site:	Midland
Issue date:	09/25/1981
From:	Tedesco R Office of Nuclear Reactor Regulation
To:	Jackie Cook CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
References
ISSUANCES-OL, ISSUANCES-OM, NUDOCS 8110200142
Download: ML20031F563 (3)

Text

..

l m

n Y'

OISTRIBUTION bec: Local PDR Docket NRC PDR SEP 2 51961 LB#4 Reading TERA DEisenhut NSIC EAdensam TIC DHood AC 6

Docket Hos. 50-329 OM, OL MDuncan g d.l_lh and 50-330 OH, OL RLTedesco ff'p/

RVollmer

1. 7 TMurley J/

N\\

I f ' b(

79 Mr. J. W. Cook JPKnight

\\T $

Vice President RMattson j~

Np N Consumers Power Company RHartfield, MP 10 1945 West Parnall Road OELD Jackson, Michigan 49201 01&E(3)

Subject:

Staff Concurrence on Surcharging of Valve Pits for Borated Water Storage Tank Foundations References : (1) Interim 50.55(e) Reports 81-03 dated February 20,1981, April 3,1981. June 12,1981. June 26,1981 July 21,1981 and August 28, 1981

~

(2) Structural Dr ign Audit by NRC Staff of Midland Plant, April 20-24s 1981. Am Arbor, Michigan (3) Meetings of May 4-6, 1981, to discuss Soils Remediatior, Bethesda, Maryland (4) Meeting of August 25. 1981, Midland, Michigan (5) Telephone conference on' July 30, 1981, August 12 & 14, 1981, September 10 & 11, 1981 By several interim 50.55(e) reports, meetings and telephone conversations (Reference 1-5), you have informed us of the status of the cracks in the concrete foundations of the Borated Water Storage Tanks (BWST) for Midland Plant, Units 1 and 2 and your preliminary plans for remediation. Your plans for remediation include, in part, surcharging a portion of the BWST valve pits and the surrounding area in order to consolidate the fill beneath the pits, reduce residual settlement during plant life, reduce distortion of the ring wall foundation, partially close existing cracks, and reduce tank shell deformation. As noted in Mr. J. Keppler's letter of July 13, 1981, you have agraed that tiie surcharging would not begin until conferences with the NRR staff were completed. Your letter of August 28, 1981, states your belief that resolution of NRC concerns has been achieved and requests NRR concurrence of the proposed t.orcharge program.

Your plans call for daily visual inspection of cracks in the BWST ring walls and valve pits during the surcharge period. You have also committed to stop further loading if a maximum 1/2-inch settlement is reached prior to full surcharge loadir,a to provide for engineering evaluations. We find these plans to be acceptable, but not sufficient. Our approval recognizes your adoption of two further conditions:

a n110200142 8109'2F PDR ADOCK 05000329 A

P DR.,,,

su.uue) or.re >

OFFICIAL RECORD COPY usceo. mi--m m me ronu m pow mcu oua

s F

J. W. Cook..

s t

1.

You state that, while it is not anticipated that existing cracks will widen or that significant new cracks will form, any new or existing cracks in excess of 10 mils during the surcharge program will be monitored and s

j the results reported to the NRC upon removal of the surcharge. The

(

,c

' absence of any immediate actions to assure that cracks approaching acceptable limits during the program will be teminated in a timely manner was unacceptchle to the NRC staff. You, therefore, have also committed that in the event that the monitoring program should indicate a crack reaching or exceeding 16 mils, then the last increment of surcharge which was added prior to start of crack growth will be removed imediately and any further surcharge addition will be prohibited pending engineering evaluation and further NRC staff concurrence. This, of course, excludes the existing 20pil crack already known to exist at the ring-pit interface of Unit 1.

C 2.

You state that propagation of a crack from the tension zone of the wall is not expected to occur because the ultimate moment capacity of the valve pit wall is governed by the yielding of the reinforcement steel. Your expected limit of new crack propagation is 18 inches from the top of the valve pit roof slab. However, your plans provide no immediate action in the event a crack should propagate above this 18 hch value. You, therefore, have committed that in the event a crack should propagate to within 18 inches from the top of the valve pit roof slab, then the last increment of surcharge which was added prior to start of crack propagation will be removed immediately and any further surcharge addition will be prohibited pendir 1 engineering evaluation and further NRC staff concurrence.

On the basis the above two additional committments, the NRC staf f concurs with your plans to commence surcharging of the BWST valve pits.

1 Our concurrence to begin this activity does not address the adequacy of the proposed remedy to achieve its intended purpose nor does it have any effect on any other remedial action that may be required as a result of the staff's OL review or as a result of the OL-0M hearing. Rather, the staff's review at this poi't has been limited to assurance that proper precautions are or will be in place to preclude potential detrimental effects due to surcharging.

Sincerely, Robert L. Tedesco, Assistant Director for Licensing Division of Licensing cc: See next page W

av c

e..E.,. ( J....

g

./

DL:LB#4 /..

DL:LB#4.....,.f.... iD omcs >

DHgg,d,Q b[,

..EAdepd,,,(,,RLTe., s,co... g J,7,,,,

sumoo

..yL'.6.1..

..,M..L61....... h.9Jg.81.....Y&.M.8f...

omy OFFICIAL RECORD COPY uso m a n - m eco nac ronu ns pa-m Nncu ona

~.

g

~

J. W. Cook 1.

You state that, while it is not anticipated tnat existing cracks will widen or that significant new cracks will form, any new or existing cracks in excess of 10 mils during the surcharge prograin will be Inonitored and the results reported to the iGC upon removal of the surcharge. The absence of any inaediate actions to assure that cracks approaching acceptable limits during the program will be terminated in a timely panner was unacceptable to the luc statf.

You, therefore, have also coi.1mitted that in the event that the monitoring prograa should indicate a crack reaching or excceding 16 nils, then the last increment of surcharge which was added prior to start of crack growth will be renoved inaediately and any further surcharge addition will be prohibited pending engineering evaluotion and further telC Staf f concurrence. This, of course, excludes the existing 20 mil crack already known to exist at the ring-pit interf ace of Unit 1.

2.

You state that propagation of a crock froia the tension zone c.t the wall is not expected to occur because the ulcimate coment cepacity of the valve pit wall is governed by the yielding of the reinforce-ment steel. Your expected limit of nw cract propagation in 18 inches from the top of the volve pit roof slab. However, your plans provide no tu.iediate action in the event a crack should propagate above this 18 inch value. You, therefore, have committed that in the event a crack should propagate to within 18 inches trou the top of the valve pit roof slab, then tne last increnent of surcharge which was added prior to start of crack propagation will be removed irmediately and any further surcharge. addition will be prohibited pending engineering evaluation and further MC Staf t concurrence.

On the basis the above two additional connittaents, the fMC Staff concurs with your plans to coac.ence surcharging of the UWST valve pits.

Sincerely, Robert L. Tedesco, Assistant Director for Licensing Division of Licensing t

Gd cc:

See next page Q,Lo c dt<v*r g p '. 66Eg

1. & 0#

3peq W

In hd

'V AD:L/DL DE '.%E6 omc4 DL:LB#4

\\LA:DL:LB#4 DLjl_B#4-

-6

.DHood:e

.MD,unc.an

..hdh!ii,

, J K., ' g h t.

.RTedehg,,,,.hh,,

9W/.81 9 0.y81 @

9,gy,81

,9/g, /,81 9/,,/81

,,9,\\,'ll.h),,

,,\\,,,,,,,

Le row.me no oo, %cu om OFFICIAL RECORD COPY

'- =>32n2.