ML20204G116

Annual Rept of Changes,Tests & Experiments for Oregon State Univ Triga Reactor for Jul 1987 - June 1988

ML20204G116
Person / Time
Site:	Oregon State University
Issue date:	09/30/1988
From:	Andrea Johnson Oregon State University, CORVALLIS, OR
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
NUDOCS 8810240055
Download: ML20204G116 (9)

Text

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• r 7 Ogegon Radiation Center Unw"bTsity , corvems. or.gon orm a=> *ew w J September 30, 1988 U.S. Nuclear Regulatory Commission ATTENTION: Document Control Desk Washington, D.C. 20555 Gentlemen:

Subject:

Annual Report of Changes, Tests and Experiments Performed Under the Provisions of 10 CFR 50.59 for the Oregon State University TRIGA Reactor (OSTR), License No. R-106 Docket No. 50-243.

The following report is submitted in accordance with the requirements of 10 CFR 50.59(b) and 10 CFR 50.4, and covers the OSTR's annual reporting period of July 1, 1987 through Junt 30, 1988. The information in this report is compiled annually and is submitted to the USNRC in this specific 10 CFR 50.59(b) report, as well as in a special section of the OSTR annual report, which is submitted in mid-September of each year.

During the specified reporting period there were two changes to the reactor facility, one change to the reactor procedures, and three changes to reactor experiments conducted pursuant to 10 CFR 50.59. There were no tests, and no new experiments performed under the provisions of 10 CFR 50.59 during the current reporting period.

The individual changes being reported are listed below by category and by title, and are described in more detail in Attachment A. Regarding this attachment, you will note that it includes a brief description of

• l ecch change followed by a summary of the safety evaluation conducted for the described change. As required, none of the changes performed under the provisions of 10 CFR 50.59 required a change in the OSTR Technical Specifications or involved an unreviewed safety question as defined in 10CFR50.59(a)(2).

1. Changes to the Reactor Facility:

a. Addition of Coilthread Inserts to the Thermal Column Graphite Stringers

b. Addition of a New Air Flow Meter to the Stack Monitoring System

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', 'USNRC September 30, 1988

2. Changes to Reactor Procedures:

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a. Revision of the General Limitations on Experiments

3. Changes to' Reactor Experiments:  ;

a. Combination of Experiment B-3 and B-8 into a Revised Version l

of Experiment B-3

b. Revision of Experiment B-11. '

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c. Revision of Experiment B-12. i We trust that you will find thir year's report to be in good order.

, However, should you require more information or have questions regarding our report, please let me know.

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) Your sincerely, ,

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Direc W , Radiation Center son ,

1 AGJ:jrs-50.59/031 i Enclosure r cc: Regional Administrator, Region V, USNRC, Walnut Creek, California ,

J OSTR Project Manager USNRC, Washington, D.C., ATTN: Mr. Al Adams ,

Director. Oregon Department of Energy, Salem, Oregon

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T. V. Andersan, Reactor Supervisor, OSTR S. E. Binney, Chairman, Reactor Operations Committee. OSTR i B. Dodd, Reactor Administrator, OSTR i i J. F. Higginbotham, Senior Health Physicist OSTR l 4

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- o ATTACHMENT A l Changes to the OSTR Facility, to Reactor Procedures and to Reactor Experiments Conducted Pursuant to 10 CFR 50.59.

l The informatic.i contained in this section of the report provides a summary l

of the changes performed during the reporting period under the provisions j l of 10 CFR 50.59. For each item listed, we have incladed a brief descrip-tion of the action taken and a sumary of the applicable safety evaluation.

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1. 10 CFR 50.59 Changes to the Reactor Facility i

There were two changes to the reactor facility which were reviewed j and performed under the provisions of 10 CFR 50.59 during the reporting {

j period. ,

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a. Addition of Coilthread Inserts to the Thermal Column Graphite t i Stringers [

! (1) Description  !

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, The thennal column graphite stringers were designed to be  !

removed by sr.rewing an extraction tool into a threaded hole f

and pulling out the stringer. Because graphite is relatively l 4 soft, the threads in the stringers had been stripped over l j the years by repeated use of the ext. action tool. In order f

i to remove a stringer from the thermal colun.n. the extraction i

tool had to be wedged into the elongated and deformed hole l and the stringer gently worked out. In order to facilitate l

removal of the stringers and to prevent further deterioration

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) of the holes. it was decided to drill and retap the graphite. >

j and then screw in metal coilchread inserts. These inserts f are manufactured in three different materials: stainless  !

) steel, inconel, and bronze. After a safety evaluation and i review by the Reactor Operations Comittee, bronze coilthreads were chosen and inserted, j

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(2) Safety Ev~iuation The coilthread inserts have greatly facilitated the removal of the graphite tnermal column stringers. They have also prevented any further erosion of the graphite holes and hence reduced the potential for activated graphite contamination on the recctor bay floor. Therefore, the inserts have enhanced safety. The handling of the graphite stringers in the thermal column is normally dictated by the gamma dose rates from the reactor core. This means that before insertion or removal of stringers the reactor typically has to be shut down lorg enough to allow the radioactivity in the fuel to decay to acceptable levels. This length of time (typically over a weekend) is sufficiently long to ensure that the Cu-64 in the bronze inserts has decayed. Therefore, there is no sig-nificant increase in hand exposure due to the use of these inserts. Indeed, the total doses to the hand may be reduced because of the 'act that the stringers can now be removed ,

more rapidly.

b. Addition of a New Air Flow Meter to the Stack Monitoring System (1) Description F

The air flow meter which was originally supplied with the OSTR stack monitor is located after the particulate and gas monitoring chambers, but before the air pump. The OSTR staff suspected that the air flow rate being indicated by the orig-inal flow meter might not always be an accurate reflection of the air flow rate through the sampling line from the stack due to the fact that there could be small air leaks into the system at gaskets and hose fittings. Clearly, it is important that the actual air flow rate through the sampling line be known and maintained at the proper rate in order to ensure that the sampling is isokinetic. Therefore, the staff decided to install an additior,al air flow meter immedi-ately upstream of the stack monitor which will indicate the actual air flow rate through the sampling line.

3 (2) Safety Evaluation The addition of this extra air flow meter enhances safety

by ensuring that there is isokinetic sampling of the re ctor stack effluent. This in turn will ensure an accurate collec-tion and assessment of any airborne particulates in the stack l effluent stream. The second (original) air flow meter down-l stream of the monitoring chambers will continue to be used and will further enhan

e safety by giving an indication of any significant air leaks into the monitoring system.

2, 10 CFR 50.59 Changes to Reactor Procedures l

There was one change to reactor procedures which was reviewed and l approved under 10 CFR 50.59 during the reporting period, j

j a. Revision of the General Limitations on Experiments (1) Description i

The sample encapsulation requirements which are specified

in the Generel Limitations on Experiments in OSTR Operating l Procedure (OSTROP) 18 were revised. The overell format of j the limitations document was also changed in an effort to l clarify the currently approved methods of encapsulation ano other limitations. This resulted in two sections dealing with encapsulation. The first section gives a table of the methods for sample encapsulation which have been found by testing and experience to be satisfactory. The second section presents the way in which other, non-specified methods of encaptulation may be approveu.

(2) Safety Evaluation All of the methods of encapsulation listed in the table in the General Limitations on Experiments are ones which have been: a) tested and shos.n to be satisfactory, or b) previously reviewed and approved for use by the Reactor Supervisor and

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the Senior Health Physicist. As a result, the current changes l merely involved writing down already approved encapsulation.

methods and rewriting existing material in a manner which  :

would make it clearer. This in turn will enhance safety, i as encapsulation requirements and other limitations on experi- l F

ments will be more understandable and thus introduce less chance for error, i

3. 10 CFR 50.59 Changes to Reactor Experiments  ;

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There were three changes to reactor experiments which were made during l this reporting period, ,

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a. Combination of Experiments B-3 and B-8 into a Revised Version  !

l of Experi mnt B 3  !

(1) Description i The old reactor experiments B-3 and B-8 were essentially f identical except for the stated purpose of the irradiation. [

Experiment B-3 was used for neutron activation analysis, and B-8 was used for radioisotope production. After a review {

of all of the reactor experimeets it was recognized that f these two experiments contained a great deal of duplication. l In addition, it was also recognized that they did nct specif-  !

ically address irradiations in all of the OSTR's available I facilities. Therefore, it was decided to combine the two I experiments into a new B-3 which would allow irradiation '

of a wide variety of sample materials in any of the OSTR  !

irradiation facilities without specifically mentioning the purpose of the irradiation. '

(2) Safety Evaluation Experiments B-3 and d-8 had been used safely for about 20 years. The new B-3 retained most of the original text, but eliminated duplication and references to the purpose of the ,

irradiation. These deletions in no way reduced the safety

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of the revised experiment, because no safety requirements i were eliminated, and the reason why samples are being irradi-ated has no bearing on reactor and radiation. safety. All of the original, as well as several additional experimental j controls, are contained in (. revised experiment description.

The deletion of certain details relating to small cadmium covers in no way reduces safaty because tests and the repeated f use of such covers over 20 years of operation have shown i that for all. facilities (except for the sampleholding du my element, which still requires an analysis) there is a negli-gible effect on reactivity.

l l b. Revision of Experiment B-11 l (1) Description 1he original B-11 experiment was written for a specific app 11- I cation involving the irradiation of natural uranium for nuclear l structure and reaction studies. The experiment description f included a number of very specific details with respect to the health physics aspects of the experiment. It was, there-f

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fore, decided to rewrite B-11 to make it more general so  !

that it could be used to accommodate irradiation of materidls i containing small quantitites of uranium and/or thorium in

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any of the standard OSTR irradiation facilities. The new l

B-11 is complementary to the revised B-3.

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(2) Safety Evaluation  !

The health physics precautions and details in the previous ,

B-11 experiment are not included in the new B-11 because  !

they are now in a number of standard Radiation Center docu- l ments. The procedures in these documents a*e at least as  !

stringent as those in the old B-11 and hence there is no i reduction in the level of safety as a result of this change.

The safety evaluation of experirnent B-3 is applicable to

6-this experiment because most of the standard paragraphs with l respect to limitations are the same. The details of the safety analysis calculations which determined the limits in the new 3-11 experiment are included as Attachment A to i

the experiment. There are two main considerations which l limit the quantities of uranium and thorium which may be l

irradiated. These are: a) the t7tal radioactivity of iodino j isotopes 131 through 135, and b) the heat generation from l the fission process. During the analysis it was determined I that the most limiting of these was the fission heat production and the resulting temperature rise, f

From actual experiments it was determined that polyethylene vials remain intact at 110*C and begin to melt at 130*C with complete melting occurring at 150*C, In addition, it is  :

known that the temperature in the OSTR rota*.ing rack can reach 70'C. Therefore, the maximum quantity of uranium or thorium allowed in samples encapsulated in polyethylene was l

limited to that which would result in a temperature rise of 30'C using the conservative assumptions outlined in Attach-ment A to the experiment.

Experiments with sealed quartz vials in aluminum TRIGA tubes showed no change in their condition even when heated up to 600'C. The melting point of aluminum is 660*C, Therefore , i the maximum quantity of uranium or thorium allowed in samples encapsulated in quartz, which in turn is placed in aluminum tubes was limited to that which would result in a temperature r rise of 500*C using the assumptions outlined in Attachment A to the experiment.  :

l All of the assumptions used in the calculation of iodine inventory and fission heating are conservative, and it is expected that actusi inventories and temperature rises will i be much less than those calculated. I

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, c. Revision of Experiment B-12 (1) Description Experiment B-12 was revised to make it consistent with the other general reactor experiments. Most of the changes merely involved a change of wording to incorporate many of the stan-dard paragraphs used in the B-3 revision. The specific con-dition requiring approval of exploratory programs by the Reactor Supervisor, the Senior Health Physicist and the Chair-man of the Reactor Operations committee (ROC) was deleted because of its inconsistency with other current procedures.

(2) Safety Evaluation Most of the wording changes v:ere minor and did not change the intent of the experiment. Other changes involved the incorporation of many of the standard paragraphs used in the revised B-3, and therefore the favorable safety evaluation for that experiment is also applicable here. The deletion

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of the condition requiring approval of exploratory programs by the Reactor Supervisor, the Senior Health physicist and the Chairman of the ROC will in no way reduce safety because  !

the experiment will either be one which meets all of the i old requirements listed in the experiment, or it will have to be specially approved by the full ROC. In addition, the Reactor Supervisor and the Senior Health Physicist still must approve any Irradiation Request submitted under this experiment, and therefore these individuals are not removed from the approval pathway for experiments performed under the provisions of experiments B-12. ,

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