ML18219D799

Response to Request for Additional Information on Ice Basket Stress Analysis, Prepared by Westinghouse Electric Corporation

ML18219D799
Person / Time
Site:	Cook
Issue date:	09/29/1978
From:	Tillinghast J Indiana Michigan Power Co, (Formerly Indiana & Michigan Power Co)
To:	Harold Denton Office of Nuclear Reactor Regulation
References
AEP:NRC:00057
Download: ML18219D799 (12)

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INFORNATIGN DISTRIBUTION SYSTEN (BIDS)

'EGULATORY DISTRIBUTION FGR INCOMING NATLRIAL 50 >> 16 REC: DENTON H R ORG: T1 LLINGHAST J DOCDATE: 09/29/78 NRC IN 5 NI PWR DATE RCVD: 10/06/78 DGCTYPE: LETTER NOTARIZED: YES COPIES RECEIVED

SUBJECT:

LTR 1 ENCL 1 RESPONSE TG NRC REQUEST OF 07/12/78... FORWARDING ADDL INFO CONCERNING SUBJECT FACILITY"$ ICE-BASKET TRE ANALYSIS... NOTARIZED 09/29/78.

PLANT NANE: COOK UNIT 1 REVIEWER INITIAL: XJN COOK UNIT 2 DISTRIBUTER INITIAL: Q

<<~~~<<<<~<<<<<<~~~H~ DISTRIBUTION OF THIS MATERIAL IS AS FOLLOWS ~~<<~<<~~<<~<<<<<<

NOTES:

I 5 E - 3 CYS ALL MATERIAL GENERAL DISTRIBUTION FOR AFTER lSSUANCE OF OPERATING LICENSF.

(DISTRIBUTION CODE AOOi)

FOR ACTION: BR CHIEF ORB01 BC+lW/7 ENCL lNTERNAL: REG NRC PDR44W/ENCL L=u-~W/2 ENCL GELD<<LTR ONLY HANAUER~~W/ENCL CORE PERFORMANCE BR4~W/ENCL AD FOR SYS 5 PROJ<<W/ENCL ENGINEERING BR<->W/ENCL REACTOR SAFETY BR<<W/ENCL PLANT SYSTENS BR<<W/ENCL EEB~~~~W/ENCL EFFLUENT TREAT SYS++W/ENCL EXTERNAL: LPDR S ST. JOSEPHr NI'k4~W/ENCL TERA<<W/ENCL NS I C< %W/ENCL ACRS CAT B4~NW/16 ENCL DISTRIBUTION: LTR 40 ENCL 39 CONTROL NBR'. 7807403 SI ZE: 2P+4P tl <<kl%% I <<%8l 4 w <<Sf<<<<%8l+SI%%%9$ <<<<%HI "'HE END <<<<<<<<<<4 <<<<<<<<<<<<<<4 k%

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Xmm70II, WI,I<.1%II I.-OW lNDIANA 5 NlcHIGAN PowER, C0MPANY P. O. BOX 18 BO WL I N G G R E EN STAT ION NEW YORK, N. Y. 10004 September 29, 1978 AEP:NRC:00057 O CXl rn cyl rn Donald C. Cook Nuclear Plant Unit Nos. 1 & 2 H CD n rn~

Wrn Docket Nos: 50-315 and 50-316 CDC=O CC/l AO License Nos: DPR-58 and DPR-74 rn cry Cyl~

Su lementar Information on Ice Basket Stress Anal sis acyl n

~rn OA7 Mr. Harold R. Denton, Director rn f

Of i ce of Nuc1 ear Reactor Regul ati on

.CA U.S. Nuclear Regulatory Commission Washington, D.C. 20555

Dear Mr. Denton:

'n his letter dated July 12, 1978 Mr. A. Schwencer of your office advised us'hat he would require additional information to complete the NRC= staff's review 'of the Donald C. Cook Nuclear Plant's Ice -Basket Stress Analysis.'e requested that we furnish information for all items contained i'n the request for additional information enclosed therein.

For further clarification of the items contained in the request for additional information, a conference call was arranged with Dr. Gluckman of your'taff on August 4, 1978. Members of the American Electric Power Service Corporation staff and Westinghouse Electric Corporation staff along with M. M. Mlynczak of your office participated in this call.

Enclosed herein is an =item by item response to your request for

'c-additional information, prepared by the Westinghouse Electric Corporation in a format agreed upon during the above mentioned conference call.

gP ts Very truly yours, CI Bg((g

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., JT:em i i ghast ice President Sworn and subscribed to before me th'is <<~day of September, 1978 in New York. County, New York.

Notary Public KATHLELN BARRY Now'York 780740306

• 'oTARY i'uiIslc, slolo ol No. 41-;d0c's y92

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Nr. Harold R. Denton, Director AEP:NRC:00057 cc: R. C. Callen G. Charnoff P. W. Steketee R. J. Vollen R. Walsh D. V. Shaller-Bridgman R. W. Jurgensen

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e ENCLOSURE 1 0

SUPPLEt<ENTARY INFOfU1ATION ON DONALD C. COOK NUCLEAR PLANT ICE BASKET STRESS ANALYSIS uestion No. 5 Provide Tables 2 through 7, referred to in ICE-TR-079, page -4.-;subsection 4.0.

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Additional Res onse No. 5 Tables 2 through 7, which are referenced on page 4, subsection 4.0, of Test

'-Report ICE-TR-079 are again submitted as an attachment to this response.

guestion No. 6

=There is still some concern that the test arrangement is,not furnishing the most conservative results. It is correct that .the ice has in some cases a stiffening effect. It is however possible to state that for certain buckling shapes the effect of ice pressure on the vertical ligament may make conditions worse.

Discuss this possibility. Discuss also the adequacy of the cruciform supports inserts to carry the ice load 'for which they are not designed. I Additional Res onse No. 6-

'. Assuming that the ice mass inside the ice baskets .is fluid and generates an internal pressure (hydraulic) on the vertical ligaments c . the basket, it is possible 'to state that for certain buckling shapes the test arrangement is less conservative. However, the internal force generated by a six foot head of ice, supported by the cruciform support inserts, when calculated would be a maximum of 0.4 lb/in acting against the vertical basket ligaments. The horizontal test qualification loads, as shown in Table 1, page 10 of -ICE-TR-079, varies from 769 lbs to 1025 lbs. This corresponds to a uniformly distributed load, acting

-against the vertical ligaments of the ice basket, of 5.34 lb/in to 7.12 lb/in, respectively. The effect of the ice pressure on the vertical'igaments would mean a 7.5Ã to 5.6/, respective]y, increase in horizontal test qualification loads'he test results are conservative because the test qitalification loads envelope the worst possible load combinations of horizontal and vertical design loads, and they were increased to include ice maldistribution, and single basket test factors.. In addition, an examination of the actual test results shows that the, baskets were tested to horizontal loads varying from 871 lbs to'721 lbs which corresponds to increases of 13$ to 68% over the required test qualification loads, which more than adequately reflects any increased load due to ice pressure.

lhe cruciform support inserts were designed, and have the primary function, to support the weight of ice above it. The cruciform inserts prevent the ice above it from falling down through into the ne'xt 6 foot ba'sket section below, in the event of a meltout during LOCA conditions-. The purpose of holding up the ice in the upper sections of the ice column is to maintain ice bed geometry

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J and not allow a bypass flow passage to open up due to some random configuration of various ice baskets having voids at various elevations.

uestion No. 7A The response does not include a discussion of the effect of concentrated loads in the hoop direction. Provide this discussion.

'dditional Res onse Ho. 7A The effect of concentrated loads (test load condition) is more conservative than

'niformly distributed loads (actual load condition) in the hoop direction. A comparison-of the shear diagram for the test case model versus the actual load model shows that on the test condition the shear loads on the hopp elements will be a minimum of ll/ higher in the local area where the concentrated loads are applied as opposed to the same area on a beam with a'niformly distributed The test setup is therefore justified by the conservative load applicaiion 'oad.

to the basket hoop elements.

'uestion No. 7C Discuss the effect of the semicircular bracket, in the axial direction.

Additional'es onse No. 7C The semicircular bracket distributes the concentrated traverse test loads on the ice basket, such that localized failure of the perforated metal is avoided.

The application of concentrated test loads along the axial direction of the ice basket is more conservative than the actual load application where the load would be uniformly distributed. A comparison of the shear diagram for the test condi.tion and actual load condition shows that the axial shear distribution

'is the same maximum value in both load cases siith the maximum shear occurring at, the ends of the basket. A comparison of the axial distribution of bending moment from the moment diagram shows that the maximum value 'occurs at the center span of the basket length for both cases, however,'he rraximum moment for the test case condition is 8.8Ã higher than the actual load case.

The concentrated traverse load application through i.he semicircular bracket is

'a more severe and conservative load condition for a buckling type failure since the vertical mesh ligaments are subjected to high shear loads locally in the area of the semicircular brackets.

guestion No. 9B Include a proof demonstrating that the requirements of General Ice Condenser Design Criteria, Section C-6: Experimental or Test Verification of Design are satisfied.

q llddi i >>1 II p II. 9B The ice basket bottom end assembly test verification via Test Report ICE-TR-079 demonstrates that the requirements of the General Ice Condenser Design Criteria Section C-6 has been satisfied. For the test, identified in ICE-TR-079, ice basket bottom end assemblies, which were manufactured to actual production drawings and procedures, with g.A. releases (ref. para. 2.0 of TP-069), were tested to loads in excess of the required qualification loads. The qualification test loads identified in Table 1 of TP-069 were developed with the required test qualification load factors as identified in the General Ice Condenser Design Criteria, and were derated by 10 percent for single test sample.

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The following table lists the actual test loads achieved i'n comparison to the required qualification test loads:

gualification Actual Test Loads Test Loads I

. D + 1/2 SSE Load Case Horizontal 1176 963 Vertical 5339 '51 33 D + DBA + SSE Load Case Horizontal 1095 .,1025 Vertical -5641 -4015 4

guestion Ho. 10A The concern is that a 2 span beam used as the model does not reproduce the same

.. .moment and shear distribution as, obtained in the actual multiple, span structure.

Your. response covered only the end connection. Cover the condition along the whole length of the structure.

Additional Res onse No. 10A The 2 span beam referenced on Figure. 9 of TP-069 does not reproduce the same moment and shear distribution as would be. obtained in the actual multiple span

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structure. The actual structure would be a 8 span beam. A comparison of maximum shear and moment diagrams" for the 8 span beam case versus the 2 span beam shows that; the maximum end support shear value for the 8 span beam would be 54 higher, the- maximum moment at the supports would be 16K lower, and the

. maximum moment in the span would be 104 higher than the 2 span beam model.

Again, as in our original response to guestion 1QA, Figure 9 of TP-069 is

..only used to calculate, the bottom connection reaction or shear load that the basket would see from the application of tare weights to the weight and pulley system used in applying the horizontal test .loads, reference Appendix B of TP-069.

The bottom connection reaction was calculated to verify, via a load cell at the basket bottom, that the .required horizontal test load to the basket had been

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F 4 4 e-achieved. The 5$ load discrepancy on the shear load would have little importance.

on the reliability of the test results since the baskets were tested to horizontal loads in excess of 105$ of the required qualification test loads as shown in our additional response to guestion No. 98.

uestion No. 11 Prove that a basket which has not "failed" but is badly deformed can stil.l ti per form i ts franc on.

Additional Res onse No.. 11 By definition a basket which has not "failed" would not be badly deformed.

. Examination of ice baskets which have been successfully tested have not been deformed to any noticeable or measureable extent. Baskets which have been tested to failure have exhibited only small localized deformations since testing would terminate after the failure

'eing defined, as in our original response point was reached. Failure point No. 11, as that point in the test when increasing the horizontal loads to the basket, the maximum vertical load cannot be maintained with'the hydraulic jack at the top of the test;fixture. That is,

, the vertical load drops'down to some-value below the maximum and cannot be held, after being 're-established, without continual actuation of the hydraulic jack.

Therefore, a basket which has not "failed", would not be deformed to any extent and would still be able to perform its function.