ML20235U501

Annual Rept 1988

ML20235U501
Person / Time
Site:	University of Illinois
Issue date:	12/31/1988
From:	Miley G, Pohlod C, Williams J ILLINOIS, UNIV. OF, URBANA, IL
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), Office of Nuclear Reactor Regulation
References
NUDOCS 8903090232
Download: ML20235U501 (8)

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ANNUAL REPORT JANUARY 1, 1988-DECEMBER 31,1988 ILLINOIS ADVANCED TRIGA FACILITY LICENSE R-115

1.

SUMMARY

OF OPERATING EXPERIENCE A. Summarv of Usaae The reactor was scheduled for use 29.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> per week and was in operation 18.4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> per week. Scheduled time is essentially unchanged from last year, but actual operational hours dropped about 20%. This drop is due to the need for shorter irradiations for neutron activation. Short runs allow for scheduling several activities during the same time period. In the following table, the per cent of time for different activities is listed. Scheduled time is that time reserved for a given operation and it includes scheduling more than one reactor facility for use at the same time while operating time is from start-up to shutdown for all the scheduled activities.

CATEGORY SCHEDULED QEERATING Research Projects 19.3% 13.3%

irradiations (samples) 46.5% 57.8%

Education and Training 23.7% 20.2%

Maintenance and Measurements 10.5% 8.7%

Presently there are two individuals with Senior Operator Licenses and one individual with an Operators License. The facility operates with a 40 hour4.62963e-4 days <br />0.0111 hours <br />6.613757e-5 weeks <br />1.522e-5 months <br /> week schedule, a staff of one and three quarters full time equivalent operators and one full time reactor health physicist.

Five individuals prepared to take the Reactor Operat'or (RO) examination, but due to course scheduling requirements only three people will be examined in February of 1989.

D. Performance Characterisih t

1. EntL_ELAme n t length and Diameter Measurements These checks were made on the B & C Hexagonals during the month of

' April. The pulse number at the time of the checks was 8949. For the eighteen elements in this region, there was a slight decrease in the length (0.7 mils).

The accuracy of a given measurement is estimated at t 5 mils. There was no change in the diameter of the fuel elements checked.

There were 318 pulses in 1988, bringing the total since 1969 to 9181.

The values for pulse height. reactor period and fuel temperature were the same at measured in previous years.

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2. Reactivity Control Rods: The measured reactivity values of the control rods have shown essentially no change. Variations between successive measurements are seldom greater than 5%.

Core Reactivity: Six new TRIGA elements were added to the core in January. The addition of these elements to the core and the redistribution of the of the older elements allowed for the recovery of about $1.15 of reactivity which had been lost due to fuel burnup over the last several years.

The net loss of reactivity attributed to fuel burnup during the year was 80.34. This value was determined by a comparison of the cold critical xenon-free control rod position at the beginning and at the end of the year. This determination takes into account the fact that six fuel elements mentioned above were added to the core. Based on an estimated 2 (20.5) cents per MW-day of operation, the reactivity loss for the year would have been approximately 30.34.

II. TABULATION OF ENERGY AND PULSING s

A. Hours Critical and Enerov Tvoe of Ooeration Time (hrsl Enerov (MW-hrs) 0-10 kW 296.0 0.04 10kW-250kW 95.7 16.39 250kW-1.5MW 455.0 390.67 Pulsing 113.8 2 17 Total 960.5 409.27 B. E.ulsitg Pulse Sire Number

$1,00-1.70 0 1.71-2.00 4 2.01-2.30 0 2.31-2.90 7 2.91-3.19 307 Above 83.19 0 Total 318 Because of the type of operation, the Hours Critical time includes instances where the reactor is not critical in the normal sense. These include the time to get eritical during a start-up, the time between pulses during continuous pulsed operation and short periods of time during sample irradiations when samples may be removed or added.

III. REAC10.R_SCRARS There were 41 unplanned scrams and no emergency shutdowns during this time period. These scrams were attributed to Instrument Malfunction (18),

Operator / Operator Trainee Error (22) and External Causes (1). This is about

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3 average' for the facility over the years, it is low considering five individuals were in training for a Reactor Operator license during this i period. d Linear Power (18) .

is a power level scram required by the Technical Specifications. It This occurs when the signal on any power range exceeds about 108% of that range.

Nine (10) of these scrams were due to electronic noise problems. In all cases i the noise was generated when the Mode Switch was moved from the Automatic position to the Steady State position. The Mode switch is cleaned periodically and old capacitors, usually electrolytic are replaced as they are identified as failed or failing. Eight (8) scrams occurred due to an operator or operator trainee turning the range switch the wrong direction.

Period Scram (7)

This scram is not required by the Technical Specifications. It occurs when the period is 3 seconds or less with the Mode Selector Switch in Automatic or Steady State position. Four (4) of these scrams occurred either when the period circuit was placed in operation at too low a power level or when the true power level was masked by high gamma current and therefore the period limiter circuit could not effectively drive the Regulating Rod in to prevent the Period Scram. Adjustment of the Log-N Channel is not practical after every shutdown. This scram is usually caused by operator trainees or student operators who are not yet familiar with this behavior.

Three (3) of these scrams were due to circuit noise of an undetermined origin.

Enel Temocrature (4)

These acrams are caused by RF signals from CB transmitters being used near the Nuclear Reactor Laboratory. When the reactor is at high power levels the RF signals are large enough to cause a fluctuation in the temperature indication circuit which can cause the channel reading to exceed the scram set point.

Loss of Power (1)

This loss of power scram was caused by a momentary interruption of electrical power to the building due to an electrical storm.

Primary Flow (11)

This scram is not required by Technical Specifications. The scram occurs if power level exceeds 1.0 MW without adequate coolant flow (approx. 550 gpm)in the primary coolant loop. This scram will also occur without adequate secondary cooling (approx. 900 gpm) is not available and power is greater than 1.0 MW. Four (4) scrams occurred due to the operator / operator trainea falling to establish Primary Coolant flow before increasing power level above 1 MW.

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4 Four (4) scrams occurred due to difficulties in maintaining secondary flow while starting up the secondary system in the winter line-up. The cooling tower is drained over night and it is not refilled until it is needed. Start i

up while the tower is filling sometimes leads to the introduction of air s .l u g s into the coolant loop. An air 31ug in the secondary coolant system will allow the secondary flow switch to trip the secondary pump which in turn trips the primary pump and this will cause a scram if the power level is greater than 1.0 MW.

1 One (1) scram occurred when the secondary system strainer became clogged with debris when switching back to the summer line-up. One (1) scram occurred when an operator was explaining the primary flow scram test and accidentally pushed the test button. One (1) scram occurred due to loss of air pressure to during an inspection of the building air the primary isolation valves compressor.

IV. Maintenance it is estimated that about 480 hours0.00556 days <br />0.133 hours <br />7.936508e-4 weeks <br />1.8264e-4 months <br /> (40 hours4.62963e-4 days <br />0.0111 hours <br />6.613757e-5 weeks <br />1.522e-5 months <br /> per month) were spent on maintenance-related activities. However 161 of these hours time are reflected in when normally the Summary of Operations. These hours account for the need to make scheduled activities could not be carried out due to necessary repairs to the reactor system and for that time when the reactor was surveillance activities. The significant items of needed to perform maintenance are given below.

Safety Rod Drive: The Rod Down limit switch was replaced on the Safety Rod. This switch causes the Rod Down light to energize when both the control rod and the drive motor are down. The switch also causes the drive motor to drive down after the falling control rod actuates the " foot switch".

Occasionally the foot switch would not close due to worn contacts and the drive motor would drift up instead of driving down.

Reaulatino Rod Uo Drive: The Up button for the Regulating Rod was replaced, it failed when the Weekly Pulse Interlock check was perfoimed prior to pulsing. This interlock is not required by Technical Specifications. The interlock prevents moving a standard control rod out of the core when the Mode Switch is placed in the Pulsing position. This failure did not affect any other interlock. It was replaced and tested before the TRIGA was operated.

Mode Selector Swl:ch: The Mode Selector Switch was replaced in an attempt to eliminate noise problems in the control console. All interlocks, switch functions and bistable functions were checked before the TRIGA was operated.

Noise problems in the control consolo have been reduced.

Safety Rod Position Indicator: The position indicator f ailed to respond indicator circuit to rod movement. The full wave rectifier bridge in the failed and was replaced.

Centrai Thimble (CT): A new Central Thimble (CT) irradiation facility was fabricated and installed after noisture was detected in the old CT on several occasions. The new CT was fabricated out of the same material as the

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5 old CT and is dimensioned identically to the old CT. The old CT was installed in 1965. It is estimated that the old CT was exposed to a fluence in excess of 10 20 neutrons /cm2

/sec over its lifetime. it is assumed that the old CT was damaged to the point that moisture would very slowly seep through its wall. No more than 1/4 inch of water was ever found in the old CT.

Fast Transient Rod: The Fast Transient Rod failed to come out of the TRIGA core when a pulse was initiated. The connecting rod between the air piston and the control rod became separated. A new connecting rod and associated components were fabricated installed and tested before the TRIGA was operated. This failure was reported to USNRC by telephone and telegram with a follow up information letter dated January 3, 1989.

V. Conditions _Under Section 50.59 of 10__CER One new experiment was approved this year. It is similar to other Nuclear Pumped Laser experiments which have been approved in the past. The experiment involves placing various IR (infrared) window materials on a carriage and positioning the carriage in the center of the Thru Beam Port. The luminescence caused by the pulse will collected and delivered to a sensor to measure the frequency' band tested.

With this experiment, evaluations of the radiation hazards, procedures for making changes to the experiment, shielding requirements and personnel safety involving the use of this equipment were reviewed and found to be satisfactory.

Testing of the Neutron Activation Tube / Cadmium Lined Neutron Activation Tube (NAT/CLNAT) Irradiation facility was completed. Procedures for handling the NAT/CLNAT were written, reviewed and approved for the use of the NAT/CLNAT. Use of the NAT/CLNAT was incorporated in to the facility Rules and Regulations as a routine irradiation facility.

Reactivity loss associated with the CLNAT were found to be 50.41 and it was found that the polyethylene sample vials would hold up satisfactorily for irradiations of up to and including two hours at full power.

Upon review of the design and performance of the NAT/CLNAT it was ,

accepted for routine use on the basis that its use did not constitute a change to the facility Technical Specifications nor does it constitute an unreviewed safety question as defined in 10CFR50.59(2).

VI. Release of Radioactive Materials Argon-41: Average concentration to environs via exhaust =

2.12 E-7 uCi/mi Total release 3458 mci Monthly range = 71-746 mci

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l Tritium: Estimation of 1.0 mci release from the evaporation of water in the reactor tank. This is based on the measured concentration of H-3 and water usage.for the year.

Effluent (sanitary sewer): Less than 20.5 uCi of beta-gamma emitting material.

V l l . E rty_l10J1me n t a l _S u r ysy s There were no environmental surveya performed in 1988 other than routine radiological monitoring. Contamination surveys are performed in the Laboratory. See Section Vill.

Vill. Personnel Radiation Exoosure and Surveys Within the_EacJLLtx A. Personnel Exoosutt Twenty-one persons were assigned film badges at the facility. Three were full time employees, while the others averaged less than twenty hours per week in the facility. The badges are sent to R.S. Landauer of Glenwood Illinois for processing. The table below gives the whole body dose equivalent received by those who were assigned film badges during 1988.

Dose Eauivalent (REMS) Number of InditJduall No Measurable Exposure 4 0.01-0.10 13 0.10-0.25 3 Above 0.25 _._t Total 21 The highest individual dose equivalent was 430 millirems. This was received by the Reactor Health Physicist who handles radioisotopes which are produced in the reactor and calibrates radiation monitoring equipment. Two other individuals received a dose equivalent above 100 millirems. They received this dose equivalent as a result of handling radioisotopes and/or special experimental apparatus. Students and visitors doses are recorded on self-reading dosimeters and were less than 10 millirems.

B. Contamination Surveys Smear samples from various locations around the laboratory are taken at periodic intervals. The removable contamination is determined by counting the smears with a gas flow proportional counter.

'The maximum contamination is usually found in the vicinity where the irradiated sample containers are handled. There were 5,018 samples irradiated in the sample area the contamination varied from 100-15,000 duringthe{

dpm/100 cmear, or 4.5E-07 to 6.8E-5 uCi/cnI. In the control room area the maximum was 200 dpm/100 cm 2 or 9.0E-07 uCi/eni. Smea a from other areas of the laboratory showed a maximum of 3,000 dpm/100 cm or 1.3E-05 uCi/eni. Clean up i

7 of these areas always results in levels of less than 1000 dpm/100 cmI or 4.5E-2 6 uCi/cm IX. Nuclear Reacter Committee Dr. Bradley J. Micklich was replaced by Dr. George H. Miley as Chairman of the Nuclear Reactor Committee for the 1988-1990 term. Dr. Micklich will remain a member of the Nuclear Reactor Committee. Dr. Miley is a Professor of Nuclear Engineering. He is the former Chairman of the Nuclear Engineering Program from the mid 1970's through the mid 1980's and has served on the Nuclear Reactor Committee previously. The following members remain on the Nuclear Reactor Committee: Dr. John G. Williams, Associate Professor of Nuclear Eng;neering: Dr. Sheldon Landsberger, Assistant Professor of Nuclear Engineering Mr. Hector Mandel, Campus Radiation Safety Officer: Mr. Craig Pohtod, Reactor Supervisor (ex-officio): Mr. Neil Barss, Reactor Health Physicist (ex-officio). All are previous members of this committee.

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University of Illinois: DepartmInt d CoUege oI Engineering Nucl:ar Enginssring

< at Urbana-Champaign 214 Nuclear Engineering 217 333-2295-Laboratory 6- 103 South Goodwin Avenue Urbana, IL 61801-2984 February 28, 1989 Director Office of Nuct' ear Reactor Regulation b.S. Nuclear Regulatory Commission Washington'D.C. 20555 Attentloni Document Control Desk.

Dear Sir

SUBJECT:

ANNUAL REPORT: Illinois Advanced TRIGA Reactor License No. R-115 Docket No. 50-151 The following is written to comply with' the requirements -of Section-6.7.f. of the- Technical Specifications and the conditions of Section 50.59 of 10 CFR. The outline of the report follows the numbered sequence of section 6'7.f~of'the Technical Specifications.

Yours truly,

%ueJPau Craig S.'Pohtod Reactor Supervisor-Mt '

d hn G. Williams Reactor t.aboratory Director l$$A k' prgeH iley, Chairman

+ Nuclear eactor Committee l

q r f' / 43 BarclayG.[/ones(( Head l Depar tmenV of Nutlear Engineering

'cc: Regional Administrator, Region lit, USNRC l

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