ML20031A822
| ML20031A822 | |
| Person / Time | |
|---|---|
| Site: | Oregon State University |
| Issue date: | 09/04/1981 |
| From: | Wang C Oregon State University, CORVALLIS, OR |
| To: | NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| Shared Package | |
| ML20031A823 | List: |
| References | |
| NUDOCS 8109280202 | |
| Download: ML20031A822 (5) | |
Text
f n
n EFe".
Red 8ation Center University corvams, oregon 97331 i=> n em L
J September 4. I m ) $ 1 1 5 ' n.
[y f<,.,
[>-
,o $;
Director Offiee of Inspection and Enforcement i
U.S. naclear Regulatory Comission 6
,k y
f Region V
?
gg 1).,/,6 1990 N. California Blvd.
Walnut Creek Plaza, Suite 202
(,d ' -
Walnut Creek, CA 94596 Re: Oregon State University TRIGA Reactor, License R-106 Docket #50-243
Dear Sir:
This report is intended to fulfill the requirements of 10 CFR 50.69 (B).
During the reporting period,1 July,1980 through 30 June,1981, there was one change to an approved experiment and there were four changes made to our facility. The changes were:
1.
Bulk shield tank water circulating system installation 2.
, Installation of a second primary-water radioactivity monitor 3.
Replacement of the water-temperature resistance thermometers with chromel-alumel themocouples 4.
Installation of a nitrogen gas purge system for the rotating rack facility 5.
Addition of Sub-part E to Experiment B24 to allow neutron radio-graphy of TRIGA fuel elements.
See attached details for an expanded explanation of these changes.
These changes do not involve a change in the techr : cal specifications or constitute an unreviewed safety question.
I Sincerely yours, o}O S
l C. ii. Wang
/
Reactor Administrator Director CllW/pc USNRC, c/o Document Management Branch, Washington, D.C.
l cc:
l Director, Office of Inspection and Enforcement, USNRC, Washington, D.C.
Oirectgr, Oregon Department gf Energyoko'kratekive? sit ?s'$n'A "U***
i I8109280303 e10904 DR ADOCK 05000
T J:
E; Director. Region V, OIE September 4,1981 1.
Bulk shield tank water circulating system installation a.
Description New piping has been added to the demineralizer system that will service the bulk shield tank. The piping is PVC plastic, and will provide an improved capability for filling and maintainir i the water level in the bulk shie' ' tank.
It will also greatly enhance the capability to circulate the shield. tank water through the particulate filter and the demineralizer tank.
Before the piping installation, the same function was accomplished by hooking up garden hoses to fittings on the "three-way" valves DV-1 and DV-16.
This set-up was cumbersome and'not very efficient.
As an added control feature, two new valves were installed with the piping (see the blue " highlighted" line on the attached schematic diagram). The new valves were assigned the numbers:
DV-3 for shield tank suction line, DV-14 for shield tank return line.
While these new valves are not actually needed, as the "three-way" valves DV-1 and DV-16 are the primary valves for controlling t.he water flow for the shield tank, they will serve as back-ups to the primary valves.
b.
Safetiy evaluation Industrial Safety will be much better since hose handling on the stairs will be eliminated. Also, potential radioactive contamin-ation problems will be eliminated due to water spillage from conn-ecting and disconnecting hoses. The net result is an improvement in overall safety.
2.
Installation of a second primary-water radioactivity monitor a.
Descripi. ion New PVC plastic piping has been added to the demineralizer system e
which accomodates a second primary water radioactivity ' monitor ~.in the demineralizer loop. The new piping incorporates plastic material consisting of valves, couplings, pressure reducers, and two pressure gauges. A lead covered stainless steel counting chamber houses a water-immersed G.M. tube, which monitors a continuously flowing sample of the primary water as it passes through the demineralizer loop. (see the green "high-lighted" line on the attached schematic diagram).
s:
s' :
1 Director, Region V, DIE. September 4,1981 b.
Safety evaluation The addition of the new water monitor will double the water surveillance capability. The new monitor is more sensitive than the existing system, which will improve surveillance of the primary water for radioactivity and overall safety.
3.
Replacement of the water-temperature resistance thermometers with chromel-alumel thermocouples a.
==
Description:==
Our TRIGA reactor water-temperature monitoring system originally used resistance thermometers and analog readout. meters. This system has been satisfactory and has monitored the water temper--
atures with a reasonable and safe degree of accuracy. However, annual calibration tests revealed minor ( 2 degrees) errors in readings. While these errors were not critical and did not con-stitute any type of safety concern, they were an annoyance when students attempted to conduct a heat balance problem.
With the experience gained from our OMEGA fuel temperature system, particularly with respect to its stability and accuracy, we decided to change all the resistance thermometers and replace them with thermocouples.
We also decided to replace the analog meters with digital L.E.D. readout panels. These changes were accomplished 10 June,1981.
b.
Safety evaluation 1.
The thermocouples were engineered as direct replacements for the resistance thermometers in the pipir.g.
2.
The L.E.D. digital readout is as accurate (to the nearest degree) as the calibrating potentiometer.
3.
A warning light flashes on the L.E.D. display if a T.C. is open.
4.
The overall system is more accurate and stable than the previous system cnd therefore improves safety.
4.
Installation of a nitrogen gas purge system for the rotating rack facility.
a.
Description It was determined through a series of tests that purging nitrogen gas into the rotating-rack facility reduced the Ar production in that facility to essentially zero, and subsequently reduced the *'Ar con-centration discharged from the facility during operation by about 30%.
As a result, a permanent N2 purging system was installed. The system consists of:
(1) a tank of liquid nitrogen positioned on the main reactor bay floor; (2) a copper tube warming coil (reactor room ambient temperature warming only); (3) tyg 1 tubing; (4) valves and fittings;
f..
t,.
Director, Region V, DIE September 4, 1981 M flow and pressure gauges tank is connected to the copper E rming coil, which The liquid N2 in turn is connected to tygon tu~aing that is routed to the reactor top. On the reactor top, the tygon is connected into a flow gauge, which is connected to a rigid discharge tube that directs the N2 down the rotating rack drive housing and into the rotating rack.
Since the rotating rack.is already vented by the argon vent system through an absolute filter, the nitrogen follows the flow path formerly used by room air.
2 purging flow rate is about 12-15 SCFH.
The N
~'
b: Safety evaluation The reduction of "Ar in the reactor exhadst system lowers radiation exposure potential, and is in line with the ALARA concept. There are no safety problems related to operation of the reactor or use of the rotating rack facility due to the new N2 purging system.
5.
Addition of Sub-part E to Experiment B24 to allow neutron radiography of TRIGA fuel elements a.
Description Experiment B24 entitled General Neutron Radiography was expanded by adding a new sub-part (B24-E) which allows the neutron radiography o'f t'oth standard and FLIP TRIGA fuel elements in beam port No.1.
b.
Safety evaluation Activation and fission product inventories in a single standard TRIGA fuel element were expected to correspond to those previously encountered in radiography of seven small, low enrichment fuel pins at the same time. This is based on the similar 2:s0 content. Although each FLIP element contains about 3.5 times the 2:5U content of a standard elemenit, activation was expected to be less than 3.5 times higher due to the burnable poison in the FLIP element. Specific procedures were written to ensure safe handling,and individual fuel element movement.
All safety considerations have been determined previously in other similar neutron radiography. Hence, the addition of this experiment sub-part to the Experiment B24 added no new unreviewed safety questions.
w...
i REVISED 00rt UPDATE 20 APR 81 g
REACTOR BAY I
HEAT EXCHANGER ROOM F _ _ __._ _ q SCcorcARY VENT l
COOur#G l
SYSTEM g
TN
-~--~
3 PRIMARY WATER PUNP
~ 490 0PM PV3 4
X IEAT EXCHANGER
[.
PV2 g
P N
PV7 WAY V
)
C
~50
=
El NI XPV1 (3-WAY DEMINERAll2ER DV5 VALVEl 4
GEIGER TUDE PUMP ~10 CPMP4 TEMPERATURE PROBE DV14N EDV3
' N
)g h SKfMtER h
i
~so P5m
?(ov22 VENT DYl7 l FrLTER l n
straion /,
PRESSURE l
}loV21 DV18 HOLES VENT I
1.
-,- m.,.RE ATCR., _
,4
[5]
0'/19
<15 P5fG kDV20 OFFUSER x
j.
DV6 SNACCESE V
BULK SittELD REACTOR TANK DT OT ADV10 MX
,TANX DV11X Xm3 l
l N
NE N
-+
-+- -pQ.-4-. -
DEMINERALIZER
+W METER CRL evts DVt3 UV12 DV7
.sentcestres,
Fig.1.68: WATER COOLING AND PURIFICATION SYSTEM i-m
>