ML18004B971

Addresses Pipe Support Base Plate Problem.Discusses Review of Support Redesigns & Capability of Anchor Bolts to Withstand Cyclic Loadings

ML18004B971
Person / Time
Site:	Millstone, Shoreham, Trojan
Issue date:	06/02/1978
From:	Noonan V Office of Nuclear Reactor Regulation
To:	Eisenhut D, Grimes B Office of Nuclear Reactor Regulation
Shared Package
ML18004B972	List: ML18004B971 ML20062B959 ML20062B961
References
TAC-07551, TAC-7551, NUDOCS 7811020343
Download: ML18004B971 (4)

Text

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ggf ViEHORAtiDUH FOR:

B.

K. Grimes, Assistant Director for Engireering and Projects, DOR D.

G, Eisenhut, Assistant Director for Systems and Projects, DOR

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FROM:

Acitng Bra nch Chi ef,

, Engineering

Branch, DOR I'IPE Sl/PPORT BASE 'PLATE PROBLEM The Enqineering Branch, Division of Operating

Reactors, has contacted

Bechtel, Bergen - Paterson,

Gilbert, and Stone 8 Hebster in regard to their past and current design p)ocedures for support base plates utilizing drilled anchor bolts.

Bechtel and Stone 5 l(ebster indicated that they became aware of base plate flexibilityeffects oti anchor bol t.pull -out loads within the past couple of years and are now considering this, in, current designs, Gilbert and Bergen - Paterson indicated they are using rigid plate assumptions for calculating bolt loads.

SUBJECT:

Review of the support redesigns at Millstone shows a considerable increase in base plate thicl;riess and anchor bolt sizes over the previous design.

The original designs by Berqen - Paterson did not meet the current rigidity requirements used by Stone 5

1 ebster.

Design deficiency reports by Long Island Lighting Company on Shoreham show that consideration of base plate flexibility has increased the pull-out loads on some bolts, and inspection of the supports h

s shown that approximately 55 percent of the anchor bolts had incorrect embedment lengths.

Currently, 15E is considering v,hether Stone E ti'ebster should be investigated for a Part 21 deviation and will be further investigating this matter.

The Engineering Branch considers the problem at Millstone where several support plates were pulled out to be a combination of base plato flexibilityand anchor bolt design problems.

Since the anchor bolts were never tested for cyclic loadings, and the lines at millstone experienced flow induced vibrations, the capability of the anchor bolts to withstand cyclic loadings should be addressed, C)

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0 Based on the above fnf~atfon, %ho Engfneer frig Dranc wo~wends that thfs be consfdcre&5 gcnerfc ftcm for anal op rat%) plants, and a vendor fnspectfon program be friplc":~ nted ~fifth 15Eto revfew the vendor dasfgn procedures used for <<nalyzfng suppo> t base plates utf1fzfng dHl led anchor telts along r fth the f'feld frrstalllatfon procedures utflfzed fn fnstallfng the anchor telts.

Also, the lo'ad ratfng techniques used by the anchor bolt manufacturers for cyclfc loadf>>gs should be ravfowed.

The Engfncerfng Bi anch has talked Mfth I/E and consider the vendor fnspectfon program to b

the r>est ef'ffcfcnt amthod of'ompletfng th necessary revfew.

The Engfrieerfng Branch estfmates approxfmately 15 nan-weeks wfll be requfred to revfew desfgn'procedures used by vendors and A/E f'frms.

The Engf>>eerfng Branch wfll se't up a rr"'Qtfng Nfth both AD's to determfne the fnterface beb;een the Engfneerfng Branch and IKE requfred to fmplement the revfew.

i The Engfneerfng Branch fs fn the process of'reparfng a f'eedback memo te DSS on the base plate problem >'hfch fs expected to,be completed

'by June 9, 1978..:

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~CC:

V. Stello, Jr,,

DOR M. Rutherford, IE U. Potopous, fE R. Vattson, DSS J,

P. Knfght, DSS R. Dosnak, DSS V. S.

Hoonan, Actfng Branch Chfef Engfnee> fgg Branch l)fv$sfon of Oper atfng Reactors

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