ML19338D525
| ML19338D525 | |
| Person / Time | |
|---|---|
| Site: | Westinghouse |
| Issue date: | 08/21/1980 |
| From: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | Damore M WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP. |
| References | |
| NUDOCS 8009230397 | |
| Download: ML19338D525 (4) | |
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UNITED STATES' '
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NUCLEAR REGULATORY COMMISSION -
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N-REGION II o,
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101 MARIETTA ST., N.W., SulTE 3100
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' ATLANTA, GEORGIA 30303 AUG 211980 Is Reply Refer To:
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70-115 Vestinghouse Electric Corporation
. n ATTN:
M. D'Amore, Manager Columbia Plant Nuclear Fuel Division -
Drawer R Columbia, SC 29205 Gentlemen:
The enclosed IE Circular No. 80-20 is forwarded for your information. If there are any questions related to the suggested actions, please contact this office.
Sincerely, James P. O'Reilly Director
Enclosures:
1.
IE Circular No. 80-20 2.
List of Recently Issued IE Circulars j
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!80092.80 dh7 m
7 SSINSi:68301 Acesssica Ns.:
8006190036
-IEC 80-20 1
~ UNITED STATES NUCLEAR REGULATORY COMMISSION ~
- 0FFICE OF INSPECTION-AND ENFORCEMENT-D WASHINGTON, D.C.
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August; 21,-1980 IE' Circular No. 80-20: CHANGES IN SAFE-SLAB TANK DIMENSIONS
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Description of Circumstances:
- During a routine / inspection at a fuel facility, an NRC inspector received a reportlof_significant dimensional' changes in safe geometry tanks. The tanks were used to.storeLlow-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 stiffened by 3/16-in. angle ~ iron.
The. cause of th'e 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 corrosion, and the high specific-i 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. 14 precondition for the calculations' required that the tank vent system be designed to' prevent accidental pressurization.
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t To prevent accidental pressurization,.a 1-1/2-in. overflow line was connected to the'l-1/2-in. vent line to the process offgas (POG) 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 POG.line. Additionally, each j
tank was provided with'a 2"'x 4" inspection port at the top with a cover free j
to." float" should pressurization occur.
l The tank dimensions.were approximately.62"_x 62" x 5 1/2".
The_ tank locations
= were parallelLto"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
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- point.in-front of'the: tank is usually' difficult so that measurements should b,e.
' made:with calipers or~similar e'quipment to. assure detection of significant distortion.
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IEC 80-20>
August 21, 1980:
Page 2 of 2
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! Notice to Licensees:
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- Allflicensees using safe-slab tanks should be aware of the possible changes'in tank dimensions resulting from hydraulic or pneumatic forces. Certain steps
_should be'takenito prevent or detect changes in safe-slab tank dimensions.
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LThese1 actions include the'following:
- (1) -Structural' analyses should be-reviewed for all vessels des;igned to be'
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geometrica11y' safe to~ assure that the possibility of pressurization has been adequately-considered. The use of tie-bars-and rigid steel supports should be considered.:ba designs for new tanks.
-(2)' The possibility offvent linesLbecoming 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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e-IEC 80-20 August 21, 1980' 1
RECENTLY ISSUED IE CIRCULARS Circular Date of No.
Subject Issue Issued to 80-20
' Changes in' Safe-Slab 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 Radioactive 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 Model 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 80-14 Radioactive Contamination of 6/24/80 All holders of power Plant Demineralized Water and research' reactor System and Resultant Internal licenses ~(operating Contamination of Personnel and construction 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 80-11 Emergency. Diesel Generator 5/13/80 All holders of a power Lube Oil Cooler Failures reactor OL or CP 80-10 Failure to Maintain 4/29/80 All holders of reactor Environmental Qualification OLs and cps of Equipment
'80-09 Problems.With Plant Internal 4/28/80 All holders of a power
' Communications Systems reactor OL or CP i'
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