ML20209H464

Univ of Utah Triga Reactor Annual Operating Rept,Jul 1985 - June 1986

ML20209H464
Person / Time
Site:	University of Utah
Issue date:	06/30/1986
From:	Crawford K, Turley R UTAH, UNIV. OF, SALT LAKE CITY, UT
To:	NRC OFFICE OF ADMINISTRATION (ADM)
References
NUDOCS 8609150260
Download: ML20209H464 (6)

Text

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The University of Utah TRIGA Reactor AnnualOperating Report July 1,1985 to June 30,1986 A. NARRATIVE

1. Operating Experience The reactor was critical 369.37 hours4.282407e-4 days <br />0.0103 hours <br />6.117725e-5 weeks <br />1.40785e-5 months <br /> and produced 30934.25 kWh of power.

The TRIGA was used for laboratory teaching, system tests, power measurements, and sample irradiations.

2. Changes in Facility Design The water recirculation system was modified to include a refrigerated water chiller. The chiller barrel is a stainless steel tube in shell design capable of heat transfer at the rate of 20 kilowatts. Primary coolant flows through the shell and around the tubes. Cold Refrigerant-12 flows through the tubes to chill the primary coolant. The freon is circulated to another tube in shell heat exchanger where the heat in dumped to waste water. With this design, it is impossible to loose primary reactor coolant to the water system, sewer system, or outside the reactor room.

A computer system has been installed to aid the reactor operator in monitoring core parameters during operation. The computer does not interact wiJi the safety systems of the control console and has no role in automatic scram actions. The computer monitors the follwing:

1. Fuel temperature

2. Powerlevel

3. Tank watertemperature

4. Chillerinlet temperature

5. Chilleroutlet temperature

6. Recirculation system flow rate

7. Primary coolant pH

8. Primary coolant conductivity

9. Area radiation levels

10. Integrated power

11. Run ti~me The regulator rod was disconnected from the control console in accordance with the Technical Specifications. The reg magnet sustained irreparable damage from localized corrosion. Therefore, the reg rod was classified as an experiment and connected to a new rod drive system driven by the newly installed computer.

Changes in performance of the reactor are outlined in the surveillance test section (A.3).

3. Surveillance Tests 8609150260 860630 PDR R

ADOCK 05000407 i

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a. Control Rod Worth

Com Configuration #18 8 Oct 1985 Safety $1.81 Shim $1.86 Reg under maintenance Excess Reactivity $0.69 Shut Down Margin $1.17 Core Configuration #19 12 Feb 1986 Safety $1.89 Shim $1.74 Reg Classified as an experiment Excess Reactivity $1.19 Shut Down Margin $0.55

b. Control Rod Inspection The biennial control rod inspection was conducted December,1985 through February,1986. The rods were removed from the tank for visual inspection.

The shim and the safety showed no signs of deterioration or damage. The reg rod sustained cladding corrosion damage. The cladding was cleaned and anodized. The integrity of the boron carbide absorbing material will be determined at a later date when the reg rod can be moved as an experiment.

Rod drop times were measured 8 Oct 1985 and 12 Feb 1986. All rod drop

times were found to be approximately 0.25 seconds.

c. Reactor Power 12 vel Calorimetric power calibrations were performed 10/2/85,3/18/86 and 4/25/86.

The following results were obtained.

Date Meter Actual 10/2/85 90 kW 73 kW 3/18/86 70 kW 81 kW 4/25/86 90 kW 89 kW The differences between meter and actual readings occur because of core configuration changes and channel calibrations. -

d. FuelInspection Biennial fuel inspection was conducted December 1985 through February, 1986. All TRIGA fuel was inspected. Six elements were discovered to have dark stains the entire length of one side. Since there was no evidence of fission t

1 products in the tank water, the cladding was considered intact and performing as designed. The six elements were the elements immediately adjacent to the reg rod when the localized corrosion occurred. One aluminum clad element was dropped during the inspection which bent the bottom locating pin. The damaged element was removed from the tank and placed alone in a fuel storage pit for fission product leakage observation. No fission products were observed in the fuel storage pit water.

e. FuelTemperature Calibration Fuel temperature circuits were calibrated 9/30/85 and 2/25/86. The circuits were calibrated to less than 5* C error over the range 20' C to 500* C.

B. ENERGY OUTPUT The reactor was critical for 369.37 hours4.282407e-4 days <br />0.0103 hours <br />6.117725e-5 weeks <br />1.40785e-5 months <br /> and produced 30934.25kWh of energy. The total hours operated since initial criticality is 1483.65 hours7.523148e-4 days <br />0.0181 hours <br />1.074735e-4 weeks <br />2.47325e-5 months <br /> and the total energy produced is 91636.51 kWh.

C. INADVERTANTSCRAMS Quantity Type Cause Action 4 Area Radiation Rear dooropened (1) Cautioned student.

Monitor Main breaker manually Reset breaker and switched by maintenance warn personnel.

personnel (1)

Line power fluctuation (1) Restart High activity sample Cautioned student.

removal. (1) 4 High Log Bumped Console (2) Cautioned student.

Line power fluctuation (2) Restart.

1 Linear Signal Spike (1) Restart.

1 Ion chamber Line power fluctuation (1) Restart.

power supply 1 Percent Power Signal Spike (1) Restart D. MAJOR MAINTENANCE During biennial inspections, the reg rod guide tube and six fuel elements were found to be corroded into the grid structure. The fuel elements were removed while the structure was still under water in the reactor tank. After all the fuel was removed from the grid, the enttire structure was removed from the tank. The safety and shim guide tubes were removed with minor difficulties and the reg rod guide tube was removed with a large laboratory compression testing machine. The upper grid plate fuel locations were milled to increase the hole

I diameter 0.03 inch. Broken guide tube fastening screws were drilled out of the upper grid plate and the holes retapped. All exposed surfaces were anodized.

The reg rod magnet sustained major corrosion damage and could not be reinstalled. The reg rod was class:fied as an experiment and connected to new rack and pinion rod drives drive by the new compu'er system.

E. CHANGES PURSUANT TO 50-59 The tank water recirculation system was modified to include a heat exchanger capable of cooling water at a maximum rate of 20 k-watts. The change was performed in accordance with item (i) of paragraph (1) of 10CFR50-59(a).The system was inspected and approved by the Reactor Safety Committee in

accordance with the original Safety Analysis Report.

The reg rod was removed from control by the console and classified as an experiment to be controlled by a newly installed computer system. This change was performed in accordance with the facility Technical Specifications and item (iii) of paragraph (1) of 10CFR50-59(a).

A computer system has been installed to aid the reactor operator in monitoring core parameters during operation. The computer does not interact with the safety systems of the contml console and has no role in automatic scram actions. This ch.inge was performed in accordance with the facility Technical Specifications and item (iii) of paragraph (1) of 10CFR50-59(a). The computer monitors the follwing:

1. Fuel temperature

2. Powerlevel

3. Tank water temperatum

4. Chillerinlet temperature

5. Chiller outlet temperature

6. Recirculation system flow rate

7. Primary coolant pH

8. Primary coolant conductivity

9. Ama radiation levels

10. Integrated power

11. Run time F. RADIOACrlVE EFFLUENTS

1. Liquid Waste -None

2. Gaseous Waste - Negligible The TRIGA was run for 329.03 k.Wh at powers to approximately 90 kW. At this level, Ar-41 production is neglibile. Our stack monitor will detect 33% of 10 CFR 20 Table I for Ar-41 and we l have seen nothing in the monitor.

3. Solid Waste -lione G. RADIATION EXPOSURES L

The average exposure for the six people working in the laboratory during the reporting year was 86 mrem / year / individual. The maximum exposure for any one person working in the laboratory during the reporting year was 160 mrem / year. No staff member received more than 200 mmm/yr.

Of the 490 visitors to the facility during the reporting year, no visitor received a measurable dose. Therefore, the average dose is negligible and the maximum dose is negligible.

Name Ekg G.M.Sandquist 90 mrem (gamma and x-ray)

K.C.Crawford 120 mrem P. Sheehan 60 mrem D. Miller 80 mmm R. Deadman 160 mrem J. Nelson 30 mrem T. Gansauge 60 mrem Control Minimal II. LABORATORY SURVEYS Surveys were conducted at eight sights throughout the laboratory which are considered as potential contamination sights. The average for the sights was 500 cpm on contact. The location of the highest contamination was a carpet,placed at the reactor room enterance for the purpose of collecting radioactive contaminants from the bottom of shoes upon exiting the laboratory. The maximum reading at this sight was 2000 cpm. Background in uncontaminated areas of the laboratory is approximately 75 cpm.

I. ENVIRONMENTAL SURVEYS i

The Air Monitoring Station operated by the Environmental Protection Agency and located outside the reactor building, has indicated no unusual changes in radiation or radioactive material concentrations during the report period.

Environmental surveys conducted on 12 Aug 1985 by the Radiological Health Office of the University of Utah indicate no unusual dose rates in the areas surrounding the l Engineering Building or anywhere on campus.

Prepared by $/Msu t//n,buh er Schior Reactor Engp/

Approved by \[

Reactor Administrator

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MERSffV SIEEbh-o OF UTAH re h,- o,,,

Document Control Center U.S. Nuclear Regulatory Commission Washington, D.C. 20555 September 8,1986 Enclosed you will find a copy of the Annual Operating Report for the University of Utah TRIGA Reactor, Docket 50-407, covering the period from July 1,1985 to June 30,1986. This report fulfills the Technical Specification 6.10 (5).

If you have any questions concerning the report please contact staff at the facility.

Sincerel ,

L o R.E. Turley Reactor Administrat r I h010 Il I

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