ML19338D537
| ML19338D537 | |
| Person / Time | |
|---|---|
| Site: | 07000033 |
| Issue date: | 08/21/1980 |
| From: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | Goetz W EMVTI, TEXAS INSTRUMENTS, INC. |
| References | |
| NUDOCS 8009230415 | |
| Download: ML19338D537 (4) | |
Text
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'q UNITED STATES
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I,,,p, NUCLEAR' REGULATORY COMMISSION
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REGION I '
631 PARK A? TENUE KING OF PRUSSIA, PENetSY LVANIA 19406
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Au i;" gust 21, 1980 Docket No. 70-33
- u., i Texas' Instruments Incorporated e
ATTN:
Mr. William K. Goetz-Manufacturing Manager Metal Systems Department 34 Forest Street '-
Attleb6ro, Massachusetts- 02703-Gentlemen:
The enclosed IE Circular No. 80-20, " Changes In Safe-Slab Tank Dimensions," is forwarded to you for information.
No written response is required. 'If you desire additional information regarding this matter, please contact this
-office.-
i
-Sincerely, w H4. W 8
e H. Grier rector
).
Enclosures:
1.
IE Circular No. 80-20 s
2.
List of Recently Issued IE-Circulars I
. CONTACT:
H. W..Crocker I
(215-337-5217) xy<
)
3 I
cc w/encls:
W. George,' Assistant Vice President and Manager Metallurgical Materials Division F. L. Sherman, Manager, HFIR Project i
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'80.09230415-i
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SSINS: ' 6830' Acc:Issien No.:
8006190036-IEC 80-20 UNITED STATES-NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION-AND ENFORCEMENT DN 1
D 9
4 WASHINGTON, D.C.
20555 "l
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 identifled 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 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 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 calc.ulations 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 (P0G) system at a point immediately above each tank.
This provided a positive overflov 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 Lis usually difficult so that measurements should be made with calipers or similar equipment to assure detection of significant distortion.
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'IEC 80-20' August 21,-1980 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 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 ~
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' 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 510DU 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 Cooloown 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-Sha'ft-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 Problems _With Plant Internal 4/28/80 All holders of a Communications Systems power reactor OL or CP 80-08
'BWR Technical' Specification 4/18/80 All holders of a Inconsistency - RPS Response General Electric Time BWR power reactor OL:
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