ML19338D535
| ML19338D535 | |
| Person / Time | |
|---|---|
| Site: | West Valley Demonstration Project |
| Issue date: | 08/21/1980 |
| From: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | Deuster R NUCLEAR FUEL SERVICES, INC. |
| References | |
| NUDOCS 8009230412 | |
| Download: ML19338D535 (4) | |
Text
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UNITED STATES -
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NUCLEAR REGULATORY COMMISSION g
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REGION I 631 PARK AVENUE 8,
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KING OF PRUSSIA. PENNSYLVANIA 19406
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August 21, 1980 Docket Nos. 50 201 Nuclear. Fuel Services, Incorporated ATTN:
Mr. R. W. Deuster President Suite 600 6000 Executive Boulevard Rockville, Maryland 20352 Gent-lemen:
The enclosed IE Circular No. 80-20, " Changes In Safe-Slab Tank Dimensions," is forwarded to 'au for information.
No written response is required.
If you desire additi.nal information regarding this matter, please contact this office.
Sincerely, tn+M N.
8 e H. Grier irector
Enclosures:
1.
IE Circular No. 80-20 2.
List of Recently Issued IE Circulars CONTACT:
H. H. Crocker (215-337-5217) cc w/encls:
J. P. Duckworth, General Manager
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8006190036 IEC 80-20 UNITED STATES NUCLEAR REGULATORY COMMISSION 0FFICE OF INSPECTION AND ENFORCEMENT bD I-WASHINGTON, D.C.
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,u August 21,.1980
'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 L
of two of the tanks had bulged and increased the thickness dimensions of the j
tanks.
i 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 the bulging was believed to le 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 t'anks 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 y
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.
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) sy' stem 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 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 Emade with calipers-or similar equipment to assure detection of significant
' distortion..
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IEC 80-20 3
August 21, 1980 P g] 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 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 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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- IE Circular 80-20 August.21, 1980 RECENTLY ISSUED-IE CIRCULARS Circular Date of No.
Subject Issue Issued to 80-19 Noncompliance with License 8/26/80 All holders of
. Requirements for Medical a medical license Licensees 80-18 10 CFR 50.59 Safety Evalu-8/22/80 All holders of ations for Changes to a power reactor Radioactive Waste OL or CP Treatment Systems 80-17 Fuel Pin Damage Due to Water 7/23/80 All holders of a Jet from Baffle Plate Corner PWR power reactor OL or CP 80-16 Operational Deficiencies In 6/27/80 All holders of a Rosemount Model 51000 Trip power reactor Units and Model 1152 Pressure OL or CP Transmitters 80-15 Loss'of Reactor Coolant Pump 6/20/80 All holders of a Cooling and Natural Circulation power reactor Cooldown OL or CP 80-14 Radioactive Contamination of 6/24/80 All holders of a Plant Demineralized Water power or research System and Resultant Internal reactor OL or CP, Contamination of Personnel and fuel cycle licensees 80-13 Grid Strap Damage in 5/18/80 All holders of a Westinghouse Fuel Assemblies power reactor OL or CP 80-12 Valve-Shaft-To-Actuator Key 5/14/80 All holders of May Fall Out of Place When a power reactor Mounted Below Horizontal Axis OL or CP 80-11 Emergency Diesel Generator 5/13/80 All holders of a Lube Oil Cooler Failures power reactor OL or CP 80-10 Failure to Maintain 4/29/80 All holders of a Environmental Qualification power reactor
.of Equipment OL or CP 80-09 Problems With Plant Internal 4/28/80 All holders of a Communications Systems power reactor OL or CP 80 BWR Technical Specification 4/18/80 All holders of a Inconsistency - RPS-Response General Electric Time BWR power reactor F
..