ML19208D723

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Forwards Interim Response to IE Bulletin 79-02,Revision 1 Containing Testing Results to Date & Schedule for Performing Addl Insps & Analyses Per Summary of Util 790706 Ltr
ML19208D723
Person / Time
Site: Fort Calhoun Omaha Public Power District icon.png
Issue date: 08/14/1979
From: Short T
OMAHA PUBLIC POWER DISTRICT
To: Seyfrit K
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
References
NUDOCS 7909290419
Download: ML19208D723 (4)


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Omaha Public Power District 1623 MARNEY a O M A H A. NE5RASKA 68102 m TELEPHONE S36 4000 AREA CODE 402 August 14, 1979

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D D Mr. K. V. Seyfrit, Director , g gg U. S Nuclear Regulatory Comission _ _

Oftce of Inspection and Enforcement ~

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b*U" IV w[]lJJ $ k _a 611 Ryan Plaza Drive

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Suite 1000 Arlington, Texas 76011

Reference:

Docket No. 50-285 Response to: NRC I & E Bulletin 79-02 Revision 1

Dear Mr. Seyfrit:

Please find enclosed an interim report containing testing results to date and a schedule for performing additional inspections and analyses, as described in the. " Summary" of the District's letter to you dated July 6, 1979.

Since Fort Calhoun Nuclear Station is not currently in an outage and the next scheduled extended outage is from approximately January 2, 1980 to March 15, 1980 for refueling, field inspection of those systems currently inaccessible will be completed during that outage. Documenta-tion of the sampling inspections will be maintained at the site for NRC review.

Sincerely, L

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Assistant General Manager TES/DDW/MEE/lp Attachment xc: LeBoeuf, Lamb, Leiby & MacRae 1333 New Hampshire Avenue, Suite 1100 Washington, D. C. 20036 7909290 /7 1054 001 9

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9 D ENCLOSURE d WD Q g l gj P ] g I. Results of Generic Testing iU JJ The terting results from the Generic Program in response to NRC I & E Eulletin 79-02 Revision 1 are being transmitted to the NRC by the Owner's G cup under separate cover.

Se District is curr.ntly reviewing this new information for its use in the

_' -t specific work in response to the above bulletin. From initial observa ions the following can be concluded from this ne.r information:

1. Shear-tensica is not necessarily a straight line relationship (i.e.

P/Pu/5 + S/Su/5 $_1.0}. Tests indicate additional strength is avail-able outside the area enclosed by the above straight line relation--

ship.

2. Cyclic loading of anchor bolta does not generally decay the static ultimate capacity of the anchor.

II. Impact en Past Inspections and Analyses The results of the testing performed for the Generic Program do not detri-nentally impact any analyses done to date. The impacts have been quite to the contrary. The new test data shows there is an inherent degree of conservatism in the previous calculations of shear-tension interaction because of two observations sited in Section I above. The District vill evaluate the effect of this.new shear-tension interaction and cyclic loading data on the results of past analyses. This effort vill be in conjunction with current verification and testing to assure that the District meets the URC's confidence level.

The District's testing program as outlined on Page 6 of our response to the NRC dated July 6,1979, vill remain as is (i.e. the bolt test value for shell type anchors equals one fifth the bolt ultimate capacity) unless the bolt design load is known to be greater than Pu/5, in which case this design load vill be used for the test load. Also, instead of testing one bolt per plate the District vill be testing that quantity of bolts in a system that vill provide a 95 percent confidence level that less than 5 percent are defective.

III. Additional Analysis 2nd Testing The District is currently proceeding with a program to inspect those seismic Category I systems not included in the " representative sample" as described on Page 3 of our response to the NRC dated July 6,1979

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III. Additional Analysis and Testing (Cor.tinued) o' il Ji g-}\JL M -'

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This inspection shall randomly inspect and test a statistical sa=ple of the bolts to provide a 95 percent confidence level that less than 5 percent defective anchors are installed in any one seismic Category I system. This sa:pling vill proceed on a system by systen basis.

Past base plate and anchor bolt analyses are being reviewed against the new dsca presented in the Generic Program. A common approach is being developed for the use of this new data in any new or revised analyses.

I7. Schednle for Ra-aining Testing and Analyses

"-~ sched"' a for performing the remaining testing and analyses vill be ccer

  • ated with the plant operation schedule. The' attached Figure 1 is a ten'.ative bar schedule for the remaining work.

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9 9 c; p - OMAHA PUBLIC POWER DISTRICT Figure 1 .

EU FORT CALHOUN, UNIT #1 -

tr_7 Outside Containment

{Q (J , Tentative Schedule for Remaining Work --- -

Inside Containment t___3 (, In Response To

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t NRC I & E Bulletin 79-02 Revision 1 I  %^o l 1, .. -

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AUGUST 3EPTDiBER OCTOBER NOVD4BER DECEMBER JANUARY FEBFUARY

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SYSTEMb 1 6 13 20 27 3 10 17 24 1 8 15 22 29 5 12 19 26 3 10 17 24 7 1's 21 28 h 11 18 Auxiliary Coolant. --

Chemical Volume

& Control Safety Injection -

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Main Steam --- --

Auxiliary Feed- -----

water Reactor Coolant - - - - - - -

Rav Water

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Waste Disposal Fire Protection Vent Drain

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