ML20148K956

Forwards NRC Memos Re Problems W/Pipe Support Base Plate Design.Ofc of Nuc Reactor Reg States That Problems Apply to Subj Facil.W/Encl ANO:7811020332 & 7811020336.)

ML20148K956
Person / Time
Site:	Phipps Bend
Issue date:	11/02/1978
From:	Goldberg S NRC OFFICE OF THE EXECUTIVE LEGAL DIRECTOR (OELD)
To:	Buck J, Rosenthal A, Salzman R NRC ATOMIC SAFETY & LICENSING APPEAL PANEL (ASLAP)
References
NUDOCS 7811200068
Download: ML20148K956 (1)

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November 2, 1978 tf.w.... /

Alan S. Rosenthal, Esq. , Chairman Richard S. Salzman, Esq.

Atomic Safety and Licensing Atomic Safety and Licensing Appeal Board .

Appeal Board U.S. Nuclear Regulatory Commission U.S. Nuclear Regulatory Commission Washington, D. C. 20555 Washington, D. C. 20555 Dr. John H. Buck Atomic Safety and Licensing Appeal Boarc'. C es, ,

U.S. Nuclear Regulatory Commissicn / <g Washington, D. C. 20555 ..

4 In the Matter of TENNESSEE VALLEY AUTHORITY 4A $9, V[9 :sT-(Phipps Bend Docket Nof.Nuc,lcaH11 Errttr nd2) 50-55'3' ar( ant ,d 50_5_54 h 6 x_ 2 4 Gentlemen: m Enclosed are.recent internal NRC memoranda discussing certain problems experienced in connection with pipe support base plate design. The NRC Office of Nuclear Reactor Regulation (NRR) has informed us that the problems discussed in-Mr. Stello's memo-randum, dated September 28, 1978, are applicable to the Phipps Bend facility, and that the NRR Division of Systems Safety is presently reviewing this aspect of piping design analysis on a ,. '

case-by-case basis under Standard Review Plan Section 3.9.3 -

ASME Codes 1, 2 and 3 Components, Component Supports and Core Support Structures. If the Board or any of the parties wish additional information, please advise us.

Sincerely, c 1 - d.<.3 6 g

Steven C. Goldberg Counsel for NRC Staff

Enclosure:

Memo 9/28/78 Stello to Grossman, w/encls cc: -See page 2 -

78112000% Q

2- s cc w/ enclosure:

Edward Luton, Esq.

Dr. David R. Schink Mr. Ernest E. Hill Ms. Phylis Pierce William B. Hubbard, Esq.

William M. Barrick, Esq.

W. Walter LaRoche, Esq.

Atomic Safety and Licensing Board Panel Atomic Safety and Licensing Appeal Panel -

Docketing and Service Section I

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e e- NUCLEAR REGULATORY COMMisslOM j j WASHINGTON, D. C. 20553 e? e l '4 4s?

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• s ,se* GEP 2 e ny MEMORANDUM FOR: Milton'J. Grossman, Hearing Division Director and Chief Counsel, OELD FROM: Victor Stello, Jr., Director Division of Operating Reactors, NRR I

SUBJECT:

BOARD NOTIFICATION - PIPE SUPPORT 3ASE PLATE DESIGN The attached memorandum to R.oger Mattson, dated June 28, 1978, presents information concerning failures of safety-related pipe supports at ment at Shor, Millstone eham Unit 1. 1 and design deficiencies As indicated on similartwo in the attachment, equip-factors appeared' to contribute to failure of anchor-bolt connec-tions of pipe supports. These are, 1) the design assumption that base plates perform structurally as rigid load-bearing members when they may be flexible members, and 2) incorrect anchor bolt torquing.

Recent audits of Architectural Engineering firms and assessments of the actions taken at Millstone, as noted in the attachment, provided the following. general information:

1. During the last few years, the' A/Es have changed their design and installation procedures for concrete embedded pipe supports.

2. Past-and current design and insta11ation' procedures vary amo.ng the A/Es,

3. In the past many of the pipe support designs have been con-tracted, and were done with methods not known by the principal A/Es, .

We have concluded that the more detailed information required must be obtained from each operati.ng facility. We are prepari.ng a generic t

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Milton J. Grossman -

letter to each operating facility requesting detailed design, installation, and testing information of concrete-embedded anchor-bolted pipe supports of safety-related equipment.

We recommend that this inforniation be' provided to the follouing Boards:

1. Monticello(FTL)

2. Indian Point 1,2,3 (Seismic Design)

We will provide an assessment of this issue upon completion of our evaluations.

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VictorSteflo,Jr., Director -

Division of Operating Reactors Office of tiuclear Reactor Regulation

Enclosure:

June 28, 1978 memo, Stello to Mattson cc w/ enclosure:

D. Vassallo V. Stello -

R. Mattson R. Bevan' L. 01shan L. flichols V. Noonan A. Schwencer T. Ippolito J. Fair

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MEMORANDUM FOR: R. J. Mattson, Director .

Division of Systems Safety Victor Stello, J,r., Director FROM:

Division cf Operating Reactors

SUBJECT:

OPERATIflG EXPERIENCE MEMORANDUM NO. 13 PIPE SUPPORT BASE PLATE PROBLEM PROBLEM Recently during intervice inspections at Millstone Unit 1, structural failures of rigid pipe supports for class 2 safety equipment were observed. These inspections, recently implemented at Millstone, were conducted i,n accordance with Section XI of the ASME Code, as endorsed by regul'ation, 10 CFR 50.55 a(g), in February 1976.

Several base-plate anchor bolts of pipe supports in the Core Spray and the Low Pressure Coolant Injection Systems at Millstone were not properly embedded; and, in some cases the anchor bolts were completely pulled out and no supporting function was provided.

Deficiency reports, in accordance with 10 CFR 50.55(e), filed by -

Long Island Lighting Company, on Shoreham Unit 1, indicate that design of base plates with drilled anchor bolts using rigid plate assumptions has resulted in underestimation of loads on some anchor bolts. Inspection of anchor bolt installations at Shoreham has shown over fifty percent of the bolt installations were deficient. Supports for both piping systems and electrical raceways have been reported as deficient at Shoreham. .

PRESUMED CAUSE It is currently believed that two interacting factors contribute to tne failure of the supports. First, the design assumption that the base plates perform structurally as rigid instead of flexible members may provide low estimates of imposed loads on the supports.

Secondly, incorrect anchor bolt embedment may also contribute to insufficient support.

- The attached memorandum from V. Noonan to B. Grimes, dated

, June 2, 1978, provides additional information. .

-2 SAFETY SIGNIFICANCE Depending on equipment layout, improperly designed or installed anchor supports could: *

1. result in loss of support function in some cases; and,

2. result in high stressing of piping systems during a seismic event or during a significant flow transient. .

REPAIR Millstone with assistance from Teledyne Engireering has completed design modifications and repairs. These changes include increased base plate thickness and larger anchor bolts for failed supports.

Shoreham in conjunction with Stone and Webster is evaluating both piping and electrical type supports. The review is scheduled to be completed by December, 1978.

DDR ACTION The Engineering Branch will review the design procedures used on operating plants to determine anchor bolt loads, the techniques used to determine load ratings for anchor bolts, and the installation procedures.

' This review will be done through an A/E vendor inspection audit in conjunction with IE. These A/E audits will be started during early July, 1978 We anticipate that criteria will be devaloped for design and installation of base plate-anchor bolt assemblies, and those operating plants requiring corrective action will be identified.

Additionally EB staff will further assess the occurrence and corre'ctive actions taken at Millstone.

REC 0"MEMDATIONS We recommend that this problem be addressed on all CP and OL reviews.

At this time it appears that consicerations should be given to the analytical methods used to.. determine whether or not base plates behave as flexible or rigid members. This in turn may effect the anchor bolt size and embedment to properly cope with loads imposed on the supports.

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-l It;may_be' appropriate to require that applicants provide for review. '

their:

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. methods for determining base plate thickness and anchor. bolt loads; i

2. criteria.for anchor bolt installation; and, t

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c3 3ridforload-ratingtechniquesfor'anchorbolts, ic loads. including We'shall issue with coordinate your staff. our meetings, discussions and evaluations of this Supplemental information will be provided.

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' . . .;;/ ! . y ', . , ?n Vic' tor Stello, Jr., Director it Division of Operating Reactors-PRIl4CIPAL DOR PERSONNEL Il Reviewer: J. Fair

Enclosure:

Memorandum dated 6/2/78 cc: w/ enclosure '

E. G. Case- '

S. Hanauer .

R. S. Boyd H. R. Denton i

- F. Schroeder -

DSS AD's .

DDR AD's D0R BC's

' DDR SL's

, J. Fair W . Nichols. .

L W. Rutherford

• J.-Sniezek l . .

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HEMORANDUM FOR: B. K. Grimes, Assistant Director for Engineering and Projects, D0R '

D. G..Eisenhut,-Assistant Director for Systems and Projects, 00R

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FROM: Acitng Branch Chief, .

Engineering Branch, D0R

SUBJECT:

PIPE SUPPORT BASE PLATE PROBLEM The Engineering. Branch, Division of Operating Reactors, has contacted-Bechtel, Bergen - Paterson, Gilbert, and Stone & Webster in regard to their past and current design procedures for support base plates utilizing drilled anchor bolts. Bechtel and Stone & Webster indicated that they became aware of base plate flexibility effects '

on anchor boltepull-out loads within the past couple of years and are riow considering this in current designs. Gilbert and Bergen - Paterson indicated they'are using rigid plate assumptions for calculating bolt loads. ,

3 Review of the support redesigns at Millstone shows a considerable increase in base plate thickness and anchor bolt sizes over the  !

previous uesign. The original designs by Bergen - Paterson did not meet the current rigidity requirements used by Stone & Webster. -

Design deficiency reports by Long Island Lighting Company on 3 Shoreham show that consideration of base plate flexibility has .

increased the pull-out loads on some bolts, and inspection of the supports has shown that' approximately 55 percent of the anchor ,

a bolts had incorrect embedment lengths. '

Currently, l'&E is considering whether Stone & Webster 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 plate flexibility ano anchor bolt design problems. Since the anchor bolts were never tested for cyclic lot. dings, and the lines at Millstone experienced flow induced vibrations, the capability of tne anchor

• bolts to withstand cyclic loadings should be addressed.

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Based on the above infomation, the Engineering Branel recomends that this be considered a generic item for all operatt .g plants, l

i and a vendor inspection program be implemented with I&E to review  !

the vendor design. procedures used for analyzing support base plates ,

utilizing drilled anchor bolts alon'g with the field ins' al11ation.

procedures utilized in installing the anchor bolts. Also, the lo'ad ,

rating techn'iques used by the anchor bolt manufacturers for cyclic loadings should be reviewed. The Engineering Branch has talked ,

with I&E and consider the vendor' ins' pection program to be the ' ost -

efficient cethod of completing the necessary review. The Engineering-  !

Branch estimates approximately 15 man-weeks will be required 1 to review. design procedures used by vendors and A/E firms. The j Engineering Branch will set up a meeting with both AD's to determine i the interface between the. Engineering Branch and I&E required to implement the review. -

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l The Engineering branch is in the process of preparing a feedback memo ,

to

'by June DSS on the base plate problem which is expected to be completed 9, 1978'. L

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H gis,in9MPo$ )2.1 I 1 V. 5. Noonan' Acting Branch Chief Engin a ring Branch Division of Operating Reactors 1  !

cc: V. Stello, Jr., DOR W. Rutherford, IE .  !

U. Potopous IE R. Mattson, DSS i

. J. P. Knight, DSS R. Bosnak, DSS .

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