ML19338D508
| ML19338D508 | |
| Person / Time | |
|---|---|
| Site: | 07000025 |
| Issue date: | 08/21/1980 |
| From: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | Remley M EMVROCIA, ROCKWELL INTERNATIONAL CORP. |
| References | |
| NUDOCS 8009230371 | |
| Download: ML19338D508 (4) | |
Text
&& -
UNITED STATES '
3l 3.
NUCLEAR REGULATORY COMMISSION ~
@, ~.
r,E REGION V
. g 1990 N. CAllFORNIA BOULEVARD
%,
- e,, o e '
' SulTE 202, WALNUT CREEK PLAZA WALNUT CR E EK, CALIFORNI A 94596
-August 21, 1980 Docket:llo. 70-25 Atomics International' Division Rockwell Internationci Corporation P
- 0. Box 309 Canoga Park, CA. 91304 Attention: ~ Dr.. M. E.. Remley, Manager, Health
^
- Services 1and Radiation Safety Gentlemen:
Tne enclosed IE' Circular ilo. 80-20 is forwarded for your information.
If there are any questions related to the suggested actions, please contact this office.
Sincerely, aMScCb R. H. Engelken Director
Enclosures:
- 1.. IE Circular tio. 80-20 2.
Recently issued IE Circulars j
~
~
~
'.t9'P.W-,'
..J,.
^4. Nd.$'.Ns..
,,a,
?
^ 8009280; S-70;
'0. <
- L 4;;=w. w m
- =
x
SSINS: 6830 Accession No.:
8006190036 IEC 80-20 UtlITED STATES NUCLEAR REGULATORY COMMISS10fl 0FFICE OF INSPECTION AND ENFORCEMENT M)O rI }
- 7 WASHINGTON, D.C.
20555 YlM I
August 21, 1980
^
jJ 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 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.
T,ie cause of the bulging was believed to be overpressurization due to partial plugging of the tank vent lines. Contributing fautors may have been excessive transfer rates, metal fatigue aggravated by corrosion, and the high specific gravity of the-stored solution.
Replacenent 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 P0G 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 51/2". 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 made with calipers or similar equipment to assure detection of significant
~ distortion.
.g..
y,
,, n u:
')
.-, c i r-0:MN i
4._~
y
. y
)
7 v
- p;
~
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 -takenito.~ 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 -lities becoming plugged should be studied and.
special overflow mechanisms should be provided if pressurization by vent-line plugging is poss1ble.
(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.
k h
.('
N k
V ONW 4 V%
A s,., -.
^
s
- ;-3, ;, g o ;.m m
y.
.v.,-;+-.
r-g s
- +-~.%.
+%
b 1
5 IEC 80 '~
August 21, 1980 RECEllTLY ISSUED IE CIRCULARS Circular Date of flo.
Subject Issue Issued to 30-19 floncompliance 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 Charges to facilities with an Radioactive Waste Traatment 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 51000 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 flatural 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 inD.
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 AlI holders of a power tube 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 Problems -With. Plant Internal' 4/28/80 All holders of a power Comunications Systems reactor OL-or CP P
- N
.,a.~
t e
4EhI1/Clih[.,M.
.'.4,
.;g ( jg'?
.. O,..q
,2 gf
,