ML20086C719

Interim Deficiency Rept Re Failure of Moving Equipment Resulting in Dropping Reactor Pressure Vessel Internals. Initially Reported on 720928.Insps Indicated No Damage to Internals or Shipping Skid

ML20086C719
Person / Time
Site:	Salem
Issue date:	10/20/1972
From:	Betz J Public Service Enterprise Group
To:	Kruesi F US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20086C708	List: ML20086C719
References
10CFR-050.55E, 10CFR-50.55E, NUDOCS 8311290086
Download: ML20086C719 (4)

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s John F. Beta Pubhc Service Electnc and Gas Company 80 Park Place Newark, N J. 07101 201/622-7000 Vice-President in charge of Electric Operation October 20, 1972 4 ,

U. S. Atomic Energy Commission Directo r of Regulatory Operations 7920 Norfolk Avenue Bethesda, Maryland 200114 .

Attention of Mr. Frank E. Cruesi ~

Director .

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v Gentlemen: -

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REACTOR LOWER INTERNALS '

FAILURE OF MOVING EQUIPMENT NO. 2? UNIT SALEM NUCLEAR GENERATING STATION '-

Ad On September 28, 1972,_ at Salem Nuclear Generating Station, Lower Alloways Creek Township, Salem County, New Jersey,-

a rail cart bolster beam,<used^in the lateral movement of the No. 2 Unit reactor lower, internals along-the access bridge and- '

onto the containment building operating floor, yielded and ,

lowered the front end- of thbskid mounted internals to the '

containment operating floor; IrLaccordance with 50.55(e).of".

D 10CFR50, this incident wac. verbally reported on.Sepyember 28 to U.S. Atomic Energy Commission,-Directorateof(RegulatoryL m M^

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Operations, Region 1 as a possible reportable item.

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External and inte rnal' inspections of the internals, and shipping skid, performed at[th'e . time of the inciderit and- ,-

after the assembly had been restored-to a horizontal' position, -

indicated that there was no d'amage to the internals.nor'to the v shipping skid. There was~no was eased down as the bolsiir\evideiicE~ of: impact

' beam" yielded during since the ;the- failure-load interval. These observations are substantiated,by a mot. ion" m.

picture record of the incident. &! . e-p ,

Following the 'liiuident, procedures were' developed to -

restore the assembly.to its previous position. Work then. 2 proceeded toward the normal completion of the handling operation- /

of-upending the assembly, remova1 from the shipp.;ng skid,."and

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placement in storage in4the~ containment building. .

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, U.S. Atomic Energy 10-20-72 Commission FAILURE OF MOVING EQUIPMENT In its horizontal position on elevation 130 of the reactor containment building, the rear of the reactor lower internals skid mounted assembly rested pn an upending cart, and the front was supported by a transverse bolster beam supported at each end on a three-wheel rail truck. The towing of the assembly along the access bridge rails on elevation 130 was accomplished by an air driven winch with the towing c ible attached to the upending cart. During the towing operation, an approximate vertical misalignment of

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1/8" in the innermost rail splice presenf.ed an obstruction to the rail tru:k wheels; supporting the bolster beam at the front of the assembly. A force couple was thereby established wtich tended to rotate the bolster beam forward about its attachment poirls on the rail truck" axles. The rear flange of the bolster beam, attempting to resist the rotation, yielded, and allowed the rotation to continue. The bolster beam proceeded to yield plastically, forcing the rail tracks to spread out, and lowering the front of:the skid mounted assembly to the operating floor. The total distance that the front of the assembly was lowered was approximately 6'-6",

and the horizontal forward movement from start of descent to rest was approx imately 3 '- 10" .

. EQUIPMENT INSPECTION At the request of PSE&G, this incident was immediately reported by Westinghouse site engineers to their headquarters.

Westinghouse Core Structure Engineering, Quality Assurance and Nuclear Construction Departments became directly involved with the site engineers and PSE&G in specifying, supervising, and performing Fequired inspections. The inspections assured that no damage was custained or dimensiunal changes occurred to the lower internals which would affect the design or operation of the ecmponent.

Inspections which have been performed by Westinghouse QA and site engineers and PSE&G sponsor, engineers are:

1. External Inspection of LowerfInternals and Skid:

The wooden shims placed between the radial core support keys and tha, skid and between the plywood c flange cover and the skid remained in place and intact. The internals-to-skid tie-down-cables remained. tight with no evidence of movement away from the assembled position. The skid runner beams showed no evidence of, deflection,-the bolted joints of the skid (vere intact and tight,

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o o U.S. Atomic Energy 10-20-72 Commission EQUIPMENT INSPECTION (Continued) and the internals packaging material was intact.

The bottom flanges of the skid runners at the

, point of contact with the front truck bolster beam became slig htly beat. The inspecting parties concluded from their external inspec-tion that there was no evidence of the load shifting in the skid.

2. Internal Inspection of Lower Internals: The pads of the baffle (fuel) cavity shipping braces were found to be tight with no apparent movement from the installed poaition. The secessible lower support columns showed no evidence of movement or looseness. The baffle cavity measurements were taken and no change was noted from the measurements taken while the internals were in pre-installation storage.

The inspecting parties concluded from their internal inspection that there was no evidence of damage from the incident or other causes.

The Westinghouse Core Structure Engineering Department concurred with the inspecting engineers in this conclusion and work was resumed in placing the assembly in its storage position in the containment building.

PRECAUTIONS TO PREVENT RECURRENCE The front rail truck bolster beam was replaced by a box beam which is inherently better able to resist eccentrically I applied loads. .The original bolster beam was a wide flange beam

! with unstiffened' flanges where the load was applied. However, to~

! preclude eccentric loading, intermediate outrigger beams were placed between the bolster beam and the internals assembly skid runners in a direction parallel to the runners. Tha outriggers would then develop the necessary restorind moments should the front bolster beam and rail truck assembly encounter an obstruction.

The outrigger beams were laterally braced and stiffened.

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l' The rail splices were adjusted to eliminate steps,and steel bearing plates were used beneath the . splices.

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U.S. Atomic Energy 10-20-72 Commission l

l FO LLOW- UP On completion of erection of the clean area protective enclosure arcund the upended reactor lower internals, PSE&G will, for added assurance, have Westinghouse perform additional inspections. Should those inspections reveal previously hidden damage, an amended report will be submitted; otherwise no further reports relative bo this incident will be made.

If you should have any questions on the subject report, we will be pleased to further discuss them with you.

Very truly yours, 1

CC Mr. J. P. O'Reilly Newark, N. J.

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