ML19338D540
| ML19338D540 | |
| Person / Time | |
|---|---|
| Site: | 07000687 |
| Issue date: | 08/21/1980 |
| From: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | Mcgovern J UNION CARBIDE CORP. |
| References | |
| NUDOCS 8009230419 | |
| Download: ML19338D540 (4) | |
Text
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o, UNITED STATES NUCLEAR REGULATORY COMMISSION 3
j REGION I
$31 PARK AVENUE 84 g
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KING oF PRUSSIA, PENNSYLVANIA 19406 9 * *....
August 21, 1980 Docket No.70-687 Union Carbide Corporation ATTN:
.Mr.' James J. McGovern Production Manager, Radiochemicals P. O. Box 324_
Tuxedo, New York 10987 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.
Sincerely,
&K'% h.
B e H. Grier
' rector
Enclosures:
1.
'E Circular No. 80-20 2.
List of Recently Issued IE Circulars CONTACT:
H. W. Crocker (215-337-5217) cc w/encls:
M. H. Voth, Manager, Nuclear Operations W. G. Ruzicka, Reactor Project Engineer C. J. Konnerth, Health Physicist Dr. R. E. Bollinger, Vice President, Medical Products Division 8009280419 v
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33gy3. 6830 Accessien No.:
8006190036 IEC 80-2U-UNITED STATES NUCLEAR REGULATORY COMISSION OFFICE:0F:INSPECTI0N AND ENFORCEMENT WASHINGTON, D.C. - 20555 yn N
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%P August 21, 1980'.
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'IE' Circular No. 80-20:
CHANGES;IN SAFE-SLAB TANK DIMENSIONS i
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 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 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 (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 POG line.
Additionally, each
. tank was'provided with a 2"c 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 n
made with calipers or similar; equipment tn 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.
1These 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. uIf additional information regarding this subject is required, contact the Director of this office.
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' IE Circular 180-20
. August-2),31980
'RECENTLY ISSUED IE CIRCULARS.
. Circular..
-Date of
.No.
Subject Issue Issued to 80. Noncompliance with License 8/26/80 All holders'of' sRequirements 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
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80-16 Operational Deficiencies In 6/27/80 All holders of a Rosemount Model 51000 Trip power reactor j-Units and Model 1152 Pressure OL or CP Transmitters t
i-6/20/80 All holders of a 80-15 Loss of Reactor Coolant Pump Cooling and Natural Circulation power reactor F
Cooldown.
OL or CP 80-14 Radioactive Contamination of 6/24/80 All holders of a I
4 Plant Demineralized Water power or research System ~and Resultant Internal reactor OL-or CP, j
Contamination of Personnel and fuel cycle.
licensees 80-13 Grid Strap Damage in 5/18/80 All holders of'a Westinghouse Fue1' 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 Emergency Diesel Generator 5/13/80 All holders of a Lube Oil Cooler Failures power reactor OL or CP n
.-80 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 F
or CP-
,N 08 ~
.BWR_ Technical Specification
~4/18/80 A11 holders of a Inconsistency.- RPS' Response General Electric Time BWR power reactor O L-
..