ML19338D519

Forwards IE Circular 80-20, Changes in Safe-Slab Tank Dimensions. No Written Response Required

ML19338D519
Person / Time
Site:	07000824
Issue date:	08/21/1980
From:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
To:	Engelder T BABCOCK & WILCOX CO.
References
NUDOCS 8009230388
Download: ML19338D519 (4)

Text

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'o UNITED STATES 7

' 8-NUCLEAR REGULATORY COMMISSION o

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~ REGION 11 2

o 101 MARIETTA ST., N.W SUITE 3100 ATLANTA, GEORGIA 1%103 AUG 211980 In Reply Refer To:

.RII JPO Babcock and Wilcox Company ATTN:

T. C. Engelder, Director -

Lynchburg Research Center P. O. Box 1260

'Lynchburg, VA 24505 Gentlemen:

-The enclosed IE Circular No. 80-20 is forwarded for your information. If there a,re any questions related to the suggested actions, please contact this office.

Sincerely,

~_

James P. O'Reilly Director

Enclosures:

1 1.

IE Circular No. 80-20 2.

List of Recently Issued IE Circulars 0./

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tAccession No.:

-8006190036-

.IEC'80 A

< UNITED STATES:

~ NUCLEAR REGULATORY COMMISSION' 0FFICE:0F INSPECTION AND ENFORCEMENT g

-WASHINGTON,.D;C. l20555 S

,,a August 21,?1980' cIE Circular:No. 80-20: : CHANGES IN. SAFE-SLAB _ TANK-DIMENSIONSS w Description-of Circumstances:

=Duringea routine' inspection ~at a fuel facility, an NRC inspector received a

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report ofLsignificant dimensional changes-in safe geometry tanks. The tanks were'used to store-low-enriched:-uranium solutions from a scrap dissolver. The

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problem.was first identified when a sight glass mounted'on the large face,of'

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-one ' of three : safe-slab tanks ' cracked' from the strain of ' tank dimecsional changes. ;Further" investigation and measu'ements revealed:that the large faces.

r of two~oflthe tanks had bulged and increased the thickness' dimensions of the-

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' tanks.

The. maximum bulge occurred at the center of one of the tanks, increasing the

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tank'thickne'ss 2 1/2 in.. beyond the ' design. thickness of 5 '1/2 in.

The bulge tapered from the~ tank. centers to the designed-5.'1/2 in. at_the tank edges.

The tanks were made of 1/8-in. type 304 ' stair.less steel with the tank edges and large-faces ~ supported and stiffened by 3/16-in. angle iron.

The cause of theibulging wa;s believed to.be overpressurization due to partial I

plugging of'the tank: vent lines.

Contributing' factors may have been excessive t

transfer rates',: metal fatigue aggravated by-corrosion, and the high specific

.gravityLof the storedisolution.

' Replacement tanks were provided with tie-bars and heavier.~1/4-in. angle iron stiffeners to preserve the. thickness dimensions. Conservative calculations, taking into account' the weight of solution,1 tank dimensions, and tie-bar and stiffener strength,' indicated that required dimensions would be maintained. A

-l precondition for thel calculations required that the tank vent system be designed to prevent accidental pressuriz'ation.

-To prevent accidental pressurization, a'l-1/2-in. overflow line was connected to the.1,1/2-in.' vent line to the, process offgas-(POG) system'at a' point

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immediately.-abovefeachl tank.This provided a positive overflow as well as a-

-second vent >in'casefa plug occurre'd-in the main P0G line. Additionally, each tank-was :provided-with ~a 2"Jx"4" inspection port at the top with a cover free to "flo'at" should pressurization occur.

x (The tank 1 dimensions were approximately 62" x 62" x 5 1/2".

The tank locations

'were parallel'to and about 1'ft' removed from the scrap recovery area _ walls.

The vis'ual; detection.of the-2-1/2-in? deflection of.'the.largs tank face from,a

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point:in' front'of the tank ~is usually. difficult so that measurements should-be imade with ; calipers or sisular equipment to assure ' detection 6f significant distortion.

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IEC 80-20~

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Auguot 21, 1980 Page 2 of 2

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-Notice to Licensees:

All' licensees-using safe-slab tanks sh'ould be aware of'the possible changes in tank dimensions' resulting:from hydraulic ~or pneumatic forces. 'Certain. steps should be taken to prevent or detect changes in safe-slab tank dimensions.

These actions. include the following:

-(1) Structural ~' analyses should_ be reviewed for. all vessels designed to be geometrically: safe to assure that the possibility of preneurization has

'been adequately considered..The use of tie-bars and rigid steel supports should be considered in designs' for.new tanks.

(2) The possibility of vent lines becoming plugged should be studied and special overflow mechanisms should be provided if pressurization by vent

-line plugging is possible.

(3)- Provision should be made for routine dimensional checks of geometrically safe vessels. These checks-should be made whether or not.the vessels are.

subject to pressurization.

No written response to this circular is required.

If additional information regarding this subject.is required, contact the Director of this office.

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1. At IEC 80 20 J

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August-21, 1980 RECENTLY-ISSUED IE CIRCULARS e

Circular.

-Date of.

. No.

- Subject-

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Issue

Issued to-130-20:

Changes:in Safe-S13b 8/21/80'

'All-Part 50 and Part Tank Dimensions

'70 Fuel Facility.-

Licensees

=80-19 Noncompliance.with

8/26/80 -

-All' medical licensees License Requirements for Medical Licensees 80-18 10'CFR 50.59' Safety--

8/22/80 All power-reactor Evaluations for Changes to facilities with an ladioactive. Waste Treatment _

OL or CP Systems 80-17 Fuel Pin; Damage Due to Water-7/23/80 All holders of PWR Jet from Baffle Plate-Corner OLs and PWR cps 80-16 Operational Deficiencies In 6/27/80 All power. reactor Rosemount Model 510DU Trip

. facilities with-an Units'And Mod 1 1152 Pressure OL or a CP Transmitters --

80-15 Loss of Reactor Coolant Pump 6/20/80 All power reactor Cooling and Natural Circula-facilities with an tion Cooldown OL or CP 14 Radioactive Contamination of 6/24/80 All holders of power Plant-Demineralized Water and research reactor System'and Resultant Internal licenses-(operating

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Contamination'of Personnel and construction j

permits), and fuel cycle licensees 80-13 Grid. Strap Damage in 5/18/80 All holders of reactor Westinghouse Fuel' Assemblies OLs and cps 80-12 Valve-Shaft-To-Actuator-Key.

5/14/80 All holders of reactor May Fall Out of Place When OLs-and cps Mounted Below Horizontal Axis 11

-Emergency Diesel Generator 5/13/80 All holders of a power s

Lube Oil Cooler Failures reactor OL or CP 80-10 Failure to Maintain

-4/29/80 All holders of reac' tor ~

Environmental. Qualification OLd and cps

- of-Equipment- 09

- Probleas'With Plant: Internal 4/28/80

.All holders of a power Communications Systems reactor OL or CP' t; :-.

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