ML19338D524
| ML19338D524 | |
| Person / Time | |
|---|---|
| Site: | 07001113 |
| Issue date: | 08/21/1980 |
| From: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | Long J GENERAL ELECTRIC CO. |
| References | |
| NUDOCS 8009230396 | |
| Download: ML19338D524 (4) | |
Text
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'o,,i UNITED STATES.
NUCLEAR REGULATORY COMMISSION 4
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101 MARIETTA ST., N.W., SulTE 3100 ATLANTA, GEORGIA 30303 AUG 21'1980 In Reply Refer To:
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. General Electric Company 4TTN:
J. A. Long, General _ Manager
- Wilmington Manufacturing Department P. O.~ Box 780 Wilmington, NC. 28402 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, i
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4 James P. O'Reilly Director
Enclosures:
1.
IE Circular No. 80-20 2.
Iist of Recently Issued IE Circulars
-ce w/ enc 1:
'A. L. Kaplan,-Manager Licensing and Compliance Audits C. M. Vaughan, Manager Nuclear Materials Management
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IEC 80-20
-UNITED STATES
' NUCLEAR-REGULATORY COMMISSION l OFFICE;0F INSPECTION:AND ENFORCEMENT-
- WASHINGTON,LD.C. 20555 m "q D iAugust-21,-L1980 M
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- s IEl Circular-No. 80-20: CHANGES IN SAFE-SLAB TANK DIMENSIONS --
. Escrip' tion of Circumstances:
D DuringTa routine inspection at?a? fuel. facility,'an NRC inspector received'a report of:significant dimensional' changes.-in safe-geometry tanks. The tankr:
were.used to store. low-enriched uranium solutions from a. scrap dissolver.
The problem wassfirst identified when a sight-glass mounted on the large face of-one:of-three safe-slab tanks'eracked from the strain of tank dimensional changes. Further investigation and measurements revealed that the 1arge faces 1
of two oflthe. 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.
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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, the bulging wa.s believed to be overpressurization due to partial-plugging of the tank vent lines.. Contributing factors may have been excessive
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transfer rates, metal fatigue aggravated by corrosion, 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 sy. stem be designed to prevent accidental. pressurization.-
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 (POG) system at a point
- immediately above
- each tank. 1This provided a positive overflow'as well as a second vent in essela plug occurred--in-the' main POG line. Additionally, each tank was provided.with a;2":x'4"' inspection port at the top with a cover free to " float';'ishould pressurization: occur.
~The tank' dimensions-were approximately.62" x 62" x 5 1/2".
The tank locations Ewere parallel to and 'about'1"ft removed from the scrap recovery area'~ walls.
iThe visual' detection of the~2-1/2-in. deflection of the large ~ tank face from a
- point'in-front (of the-tankfis'usually; difficult-so that measurements should b'e
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made with! calipers'.or-similar_ equipment.'to assureLdetection.of significant distortion.-
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.IEC-80-20 JAuguot 21,~1980f Page 2 of 2 Notice to Licensees:
All licensees using' safe-slab.; tanks should be aware'of the possible changes in tank dimensions resulting'from hydraulic.or. pneumatic forces..Certain steps
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should'be taken'to. prevent-or detect changes in safe-slab tank-dimensions.
These actions include the'following:
(1)
Structural analyses sh'uld be reviewed for all vessels designed to be o
geometrically 3 ie 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 ressels. 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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s:
IEC 80 August 21, 1980-
- L RECENTLY ZSSUED 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
- 0L 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 on 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 licensecs 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 i
80-09 Problems With Plant Internal.
4/28/80 All holders of a-power
- Communications. Systems -
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