ML19338D513
| ML19338D513 | |
| Person / Time | |
|---|---|
| Site: | 07000925, 07001193 |
| Issue date: | 08/21/1980 |
| From: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Shelley W KERR-MCGEE NUCLEAR CORP. |
| References | |
| NUDOCS 8009230380 | |
| Download: ML19338D513 (4) | |
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43-UNITED STATES -
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' Docket No.70-925.
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- Docket No. 70-1193
,s Kerr-McGee Nuclear Corporation 0-ATTN:
Mr. W. J. Shelley, Director-Regulation and Control Kerr-McGee Center
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Oklahoma City,.0K 73125 t
Gentlemen:
The enclosed IE Circular No. 80-20 is forwarded for your information.
If there are any questions reldted to the suggested actions, please contact this office.
's Sincerely, E
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ames G. Keppler j
Director
Enclosure:
IE Circular
.i No. 80-20 cc w/ enc 1:
Mr. B. E. Brown, General Manager, Manufacturing Central Files PDR Local PDR NSIC
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Acc:ssion No.:
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8006190036.
IEC 80-20 UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF: INSPECTION AND ENFORCEMENT WASHINGTON, D.C.
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August 21, 1980 hh J
tul IE Circular No. 80-20:
CHANGES IN SAFE-SLAB TANK DIMENSIONS Description'of Circumstances:
During a' routine inspection at 'a fuel' facility, an NRC inspector received a report of significant dimensional changes in safe geometry tanks.
The tanks were used to store low-enriched uranium solutions from a scrap dissolver.
The problem was first identified when a sight glass mounted on the.large face of one of three safe-slab-tanks cracked from the strain of tank dimensional changes.
Further investigation and measurements revealed that the large faces of two of the tanks had bulged and increased the thickness dimensions of the tanks.
The maximum bulge occurred at the center of one of the tanks, increasing.the tank thickness 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 stainless steel with the tank edges and large faces supported and 5tiffened by 3/16-in. angle iron.
The cause of the bulging was believed to be overpressurization due to partial plugging of the tank vent lines.
Contributing factors may have been excessive transfer rates, metal fatigue aggravated by a rrosion, and the high specific gravity of_the stored solution.
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, tank dimensions, and tie-bar and stiffener strength, indicated that required dimensions would be maintained.
A precondition for the calculations required that the tank vent system be designed to prevent accidental pressurization.
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To prevent accidental pressurization, a 1-1/2-in. overflow line was connected to the 1-1/2-in. vent line'to the process offgas (P0G) system at a point immediately above each tank.
This provided a-positive overflow as well as a second vent in case a plug occurred in the main P0G line. Additionally, each tank was provided with a 2" x 4" inspection port at the top with a cover free to " float" should pressurization occur.
The tank 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 visual detection-of the 2-1/2-in.- deflection of the large tank face from a point in front of'the tank is usually difficult so that measurements should be nade with calipers or similar equipment to assure detection of significant distortion.
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I IEC 80-20
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gp August 21, 1980 Page 2 of 2-4 MNotice to Licensees:
.All1 licensees using safe-slab tanks should 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)' Structura'1' analyses should be reviewed for all vessels designed.tcr be geometrically' safe to assure that the possibility of pressurization 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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RECENTLY ISSUED IE CIRCULARS y
' Circular ~
Date of No.
Subject Issue:
' Issued to q
80-19
' Noncompliance with.
6/26/80 All medical licensees 1
. License _ Requirements-for.
Medical Licensees
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10 CFR=50.59 Safety
- 8/22/80 Al1 power reactor.
Evaluations ~ for. Changes ;to'. '
0L or CP-i facilities with an Radioactive Waste Treatment-r
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80 FueliP.in Damage Due to Water 7/23/80 All holders.of.PWR-
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Jet from Baffle Plate Corner OLs and PWR cps
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. Operational Deficiencies:In 6/27/80 All power reactor Rosemount Model 5100U Trip facilities with an
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. Loss of Reactor Coolant Pump 6/20/80 All power reactor Cooling and. Natural Circula-
'All. holders of power Plant-Demineralized Water and research reactor
. System and Resultant Internal licenses (operating Contamination:of Personnel and -. construction -
permits),-and-fuel l
cycle licensees a
80-13
- Grid-Strap. Damage;in 5/18/80 All holders of reactor.
Westinghouse Fuel Assemblies Ols~and cps 80 Valve-Shaft-To-Actuator Key 5/14/80
-All holders of reactor l
May Fall Out of Place-When OLs and cps
. Mounted Below' Horizontal-Axis.
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80-11t Emergency Diese1 Generator 5/13/80 All holders of a power Lube Oil Cooler Failures reactor OL or CP 80-10l fFailure to Maintain 4/29/80 All holders of reactor
. Environmental Qualification OLs and cps lof Equipment
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rea'ctor 0L or CP
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