ML20137X188
| ML20137X188 | |
| Person / Time | |
|---|---|
| Site: | 05000192 |
| Issue date: | 12/02/1985 |
| From: | Bauer T, Fonken G, Klein A TEXAS, UNIV. OF, AUSTIN, TX |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8512100433 | |
| Download: ML20137X188 (10) | |
Text
-
COLLEGE OF ENGINEERING
/*j Q**f
,, q
/ *Y ge$/
DepartmentofAfechanicalEngineering NuclearEngineeringProgram. Austin, Texas 78712 (312)471-3136 December 2, 1985 Standardization and Special Projects Branch Division of Licensing Nuclear Regulatory Commission Washington, D.C.
20555 Atten: Mr. Harold Denton Docket #50-192
Dear Sir:
Enclosed is the reply to questions regarding The University of Texas dismantling and decommission plan (letter submitted May 3, 1985, and request dated August 9, 1985).
Sincerely, hm J. (3<-
Thomas L. Bauer, Ph.D.
Assistant Director / Supervisor Nuclear Engineering Teaching Laboratory Approved:
4 Dale E. Klein y--
GeAlard J. Fonken TLB :bjm Enclosures (6) cc:
Dr. E.F. Gloyna Dr. H.G. Rylander Dr. H.L. Marcus Dr. H.A. Walls Signed before me this SZ4 day of December, 1985.
Yc DA-)
l 6
Notary for the State of Te/as.
L $$
koj21 33 851202 P
CK 05000192 PDR
, - ~
a RESPONSE TO QUESTIONS THE UNIVERSITY OF TEXAS AT AUSTIN DECOMMISSIONING PLAN General 1.)
The radiation protection program for dismantling and decontaminating the TRIGA reactor facility will imple-ment periodic radiation surveys and will monitor air sam-ples within the radiation confinement area.
Area radiation surveys will be made with beta-gamma sensitive portable in-struments.
Air samples will be taken with a continuous air monitor.
Air particulate samples accumulated on fixed fil-ters will provide indication of airborne radioactive mater-ial concentrations.
A continuous monitor of the activity on the filters will provide surveillence of the air borne concentration of materials and provide caution alarms for high levels.
The periodic analysis of filters removed from the monitor will provide an evaluation of the type of radioisotop~es that are present.
The activity monitor will be provided by a. Geiger tube detector and an activity evaluation may be provided by a germanium gamma ray de-
'toctor.
Indications of excessive levels of airborne radio-nuclides will require the implementation of a respiratory protection program, although an alternate protection pro-
,w-w w
.---ys m
w--
p2 gram may be implemented for protection against dust.
A high volume air sampler is maintained by the University radiation safety office to aide the assessment of airborne
~ radiological materials.
Respiratory protection for workers will be provided by half-face masks with filter cartridges appropriate for the protection of the identified airborne materials.
Training will be implemented to' instruct workers of the purpose and.use of the masks and checks pro-vided for fitting the masks to personnel.
2.)
Estimates of the time for activities relating to potential airborne radioactive materials, the demolition of the pool tank and concrete structure, indicate a period of approximately 40 work days in which airborne radioactive materials are most probable.
A bioassay program will pro-vide base line asasurements via urine samples of workers prior to participation in the dismantling processes.
A I
follow-up measurement will be performed upon termination of the work.
Bioassays at periodio intervals may be imple-mented if sample measurements indicate that a significant l
risk of dose from respiratory conditions exist.
Doses from airborne radioactive materials are not anticipated j
to be significant.
3.)
Pocket chamber dosimeters and TLD devices are s
available for daily evaluation of radiation exposures.
l t
l
p3 These devices will supplement the use of film badge dosi-meters to provide information for review of daily expo-sures and control of the total permissible limit for personnel exposure.
An evaluation of the task, radio-logical conditions, and radiation survey measurements shall be applied to determine the supplemental use of pocket chambers or TLD devices.
A daily use of sup-plemental dosimeters with the film badge monitors will be applied for tasks in which radiation exposures could occur that are a significant fraction of the permissible dose.
For other activities or tasks that do not repre-sent signficant radiation exposures film badge dosimetry may be considered sufficient.
4.)
Film badge dosimeters are routinely used by University personnel for personnel monitoring.
These dosimeters are provided by a certified service and would also be used for personnel during dismantling and decommission activities.
Film badge exposure periods are at'two week intervals.
Snecific Ouestions 1.)
Sodium-24 activity is a short half-life (18 hour2.083333e-4 days <br />0.005 hours <br />2.97619e-5 weeks <br />6.849e-6 months <br />) activity observed in the coolant water.
Presence of the sodium ion in the water is the result of extended operation of the purification system resin bed beyond the e
._..m..
p4 optimum conditions for its designed deionizing function.
Exposure of the sodium ion to the neutron flux generates sodium-24 through neutron activation at times when the re-actor is in operation.
At the time of dismantling any activity of sodium-24 will have decayed to negligible amounts since a shutdown period of 30 days prior to activities represents about 40 half-lives.
Periodic samples of the pool water are measured for gross beta activity.
A total of 20 measurements of pool water activity during the 1985 period yielded results of less than about 4x 10-6 pc/cm3 and eleven data points that averaged 1.8 x 10-4 1 1.3 x 10-4 pc/cm3, which is lower than the concentration for Na-24 in 10CFR20 l
Table I column 2.
Half-life measurements of samples cor-i i
relate with the 15 hour1.736111e-4 days <br />0.00417 hours <br />2.480159e-5 weeks <br />5.7075e-6 months <br /> decay half-life for Na-24.
Isotopes such as Na24 and Cl38 are common contam-instes introduced into the pool on the surface of ma-terials.
Other elements commonly present in small quantities are Fe55, Fe59, Cr51 and Zn65 from stainless steel components in the pool.
Another significant element may be Co60 No analysis of the isotopic com-position of the current pool water has been made be-cause of the low total maximum activity of ~ 10-6 pCi/cm3 An analysis of the resin and more sensitive
p5 measurements of the water are planned after reactor operation is curtailed in preparation for disposition of components.
Areas of the facility cutside the reactor pool structure meet the surface contamination criteria by Reg. Guide 1.06.
A few localized spots such as radio-active waste storage area, radiochemistry hood, glove box and discarded reactor experiment components may not meet the releasable criteria of Reg. Guide 1.86.
Sus-pect areas and components will be examined and disposed or decontaminated appropriately.
Contamination levels of accessible surfaces are inferred from routine surveys to be less than 200 dps/100 cm2 Levels associated with components utilized in handling radioactive materials are inferred from records of contamination maintained on specific instances.and components with values typically between 500-1000 dpa/100 cm2 These components are experiment tubes, fuel element shield, radioactive material hood and other components.
At this time no known sources are expected to exceed 5000 dpa/100 cm2 outside the pool structure and only a few are expected to exceed 200 dpa/100 cm2 2.)
Qualifications for health physics personnel at the University are specified by job descriptions maintained J
. ~,.,_
p6
~
by the Director, Office of Personnel Services and Employee Relations.
Two classifications of safety personnel are applicable to the health physics requirements.
One is the Safety Coordinator with educational requirements of a bache-lors degree in engineering, physics, environmental health or related area and experience of five years in the field of radiological health, industrial hygiene, environmental health, or occupational safety.
Knowledge must include working with regulations and standards associated with the Texas Ref.ulations for Control of Radiation and Federal Standards for Protection Against Radiation.
Another classification is a Radiation Safety Specialist with educational requirements of a bachelors degree in engin-eering, physics or related field and experience of three years in radiation safety or radiological health.
Implementation of the Radiation Protection Program will include at least the review and may include.direc-
. tion of the Safety Coordinator; although a health physica co sultant or contractor may provide the daily on-site function.
Qualifications for the person directing the pro-gram si. tall be equivalent to the Safety Coordinator and qual-ifications for a person performing the daily activities j
shall be at least equivalent to the Radiation Safety Specialist.
p7 v
3.)
Heasurements outside the reactor facility con-sist of two fundamentally different areas.
Directions to the east and north are interior building areas and direc-tions to the west and south are exterior to the building.
No effluent pathways from the facili'd exist that would normally cause radioactive contamination in the areas other than surface contamination.
Surface contamination is routinely monitored at the source inside the facility.
Interior building areas adjacent to the facility will be checked for surface contamination.
Since no external pathways exist to areas outside the building an extensive external survey beyond the immediate vicinity of the exterior building walls is not planned except to ostablish a
typical area data.
Effluent pathways for airborne radicactive materials during operation are confined to the entrances and exists of the facility.
These confined releases are the function of a recirculating air ventilation system with leakage losses to entrances and exits.
Surface contamination sur-vey of these areas will establish airborne effluent releases.
Effluest pathways for liquid radioactive materials during operaton are limited to the sanitary sewer with the appropriate limitation of discharge quantities and concen-
p8 trations.
Samples and surveys of the sanitary drain will determine the status of drain surfaces and disposal re-quirements.
Airborne and liquid effluent pathways that are cre-ated during decommissioning activities will be treateo separately.
Monitoring of any effluents and subsequent J
sampling will be plenned in relation to the pathways created.
Sampling or surveys would be in,he area of t
the immediate effluent' release.
4.)
A possibility exists that small amounts of activated material from the concrete pool structure have been leached by ground water intrusions.
The activated material would be in the area between the pool liner and concrete structure that contains the pool.
Samples of the soil adjacent to the exterior of the concrete pool structure are to be taken to establish the extent and quantity, if any, of materials leached from the structure.
Packaging, temporary storage, and handling of the l
volumes of activated concrete are to be controlled.
However, if these activities should require or effect the areas external and adjacent to the reactor facility then an appropriate soil sample survey will be made.
l
.m.
\\
)
p9 i
i 5.)
TLD bulbs and mini rods available for assess-ment of personnel exposure are CaF2 materials.
A Victoreen model 2810 ultra sensitive reader with asso-ciated bulb devices is to be used.
Bulb sensitivities are.1mR - 100,000R and instrument readouts are auto-ranged over 7 decades.
Mini CaF2 rods encapsulated in glass are also available.
Rod sensitivities are 10mR - 100,000R.
Instrument readout is by 3-1/2 digit LED display with optional recorder output for glow curve.
Bulb exposures will be calibrated by exposure to a cali-brated Cs137 source maintained by the University Radia-I i
tion Safety Office.
6.)
Radiation surveys to determine background levels and radiation levels within SpR/hr of the back-ground will apply a pressurized ionization chamber.
The chamber will be borrowed from The State of Texas Bureau for Radiation Control and the calibration noted.
The chamber is a Reactor Stokes RSS111 p R meter (digi-tal) with a sensitivity of 1 mrad /yr (1-500 pR/hr).
s
_ _