ML20132B274

Forwards Decommissioning Plan for L-77 Research Reactor, Per Request

ML20132B274
Person / Time
Site:	05000433
Issue date:	09/09/1985
From:	Kroes R CALIFORNIA, UNIV. OF, SANTA BARBARA, CA
To:	NRC
Shared Package
ML20132B267	List: ML20132B263 ML20132B274
References
NUDOCS 8509260144
Download: ML20132B274 (2)

Text

UNIVERSITY OF dALIFORNIA, SANTA BARBARA BERKELEY

• DAVI5

• IRVINE

• LOS ANGFLES

• RIVERSIDE

• SAN DIECO * $AN IRANCIKO SANTA B ARBARA

• SANTA CRt*Z 1./

DAvio PIERPONT GARDNER Prrsident q/ the Unircraity OFFICE OF Tile Cil ANCELIDR SANTA BARBARA, CALIFORNIA 93106 ROBERT A. HUTTENBACK Channitor at Santa Barbara September 9, 1985 United States Nuclear Regulatory Ccmnission Facilities Licensing Branch Washington D.C. 20555 Dear Ccmnission; RE: Docket 50-433 On August 12 I subnitted an application to deccnnission the L-77 nuclear training reactor at the University of California, Santa Barbara and to terminate the license (R-124) when the deccmnissioning has been accmplished.

Nineteen cmples of the Decomnissioning Plan and Environmental Report were enclosed. We report was prepared by a contractor, Pocketdyne Division of Rockwell International Corporation, and reviewed by the appropriate agencies at the University. As requested, on August 23, I resubnitted the application, notarized and in triplicate. Today, my office has been asked to send three more notarized letters and another copy of the Deccmnission report. Wey will be sent today. Your attention to our request, so that the reactor can be deccrmissioned in January 1986, would be appreciated.

Sincerely, 8509260144 850909 PDR ADOCK 05000433 P PDR ,

Ro rt J. Kroes Vice Chancellor Administrative Services cc: NRC Pegion V Walnut Creek, California State of O rd i M / nia County of cia + 6,w m Am Raymond F. Sawyer P.E. Gallagher On this the (a.s ) day of <;e A e e r- , 19 W A.E. Profio before me, the undersigned Notary Public, personally appeared 4,y % <4 A K ,c, c . , proved to me on Enclosure the oath of h ,,,4 A % ,c c. to be the person whose name , % subscribed to the within instrument and acknowledged that kr executed the same for the purposes therein contained.

.< OFFICIAL SEAb > IN WITNESS 191ERE0F, I hereunto set my hand and BETTY ELIZABETH CALDERON , . .

Nota 8tY PUGUC CAUF0ANIA ,

official seal.

sANu sAR9AM COUNTY f3 C h M U* 'i7*W (A'N C4 ##U'

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o DECOMMISSIONING PLAN FOR THE L-77 RESEARCH REACTOR UNIVERSITY OF CALIFORNIA SANTA BARBARA Prepared for UCSB by i

Rocketdyne Division Rockwell International Corporation Canoga Park, California August 5,1985 l

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1.0 PLAN BACKGROUND AND MANANEMENT 4

1.1

SUMMARY

DESCRIPTION The UCSB L-77 Research Reactor is a small, solution-type nuclear reactor designed for laboratory use. It was manufactured by the Atomics International Division of North American Aviation, a predecessor of the Rocketdyne Division of Rockwell International. It consists of a reactor core tank, containing the fuel solution, within an inner shield tank, which is mounted inside a water-filled outer shield tank. The reactor is installed in Room 1251 in the east-ern end of Building 572 (Physics Unit 1) on the UCSB campus near Goleta, California. Room 1251 was created by walling off the southern portion of Room 1356, shortly after refueling and startup of the reactor.

This reactor was licensed by NRC under the room identified in the license application as the reactor facility, Facility Operating License R-124, issued December 3,1974. The reactor had initially been installed and operated at the University of Nevada at Reno, and was moved to UCSB in 1974, with startup in January of 1975. At both sites, the reactor was licensed for operation at power not to exceed 10 W (thermal).

The currently utilized laboratory space is needed for other purposes, and the academic needs for the reactor no longer justify its continued operation, so UCSB has decided to decommission the reactor, prepare the facility for release for unrestricted use, and seek termination of the facility operating license. To accomplish this, the reactor fuel solution (containing enriched uranium) and the neutron startup source (Pu-Be) will have been removed prior to beginning any dismantling operations and sent to authorized DOE facili-ties. (The Pu-Be source may be kept at UCSB under a license from the State of l California. )

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After defueling'of the reactor, under procedures of the current operating license, the external equipment (control rod drives, thimble shield plugs, off-gas and fuel valves) will be ranoved and the outer shield tank drained of 1

i water and disassembled. The inner shield tank, containing the reactor core tank, recombiner, and thimbles, will be disposed of, intact, as low-level radioactive waste. '

Because of the effective shielding surrounding th'e reactor, and the hermetically sealed system, no radioactivity, due either to activation or con-tamination, exists outside the reactor assembly itself. After disposal of the reactor and removal of associated equipment, a final radiological survey will be performed to demonstrate compliance with the criteria for release for un-

restricted use.

, The results of this survey will be reported to NRC, with the request for i I

t termination of the license. ,

The cost for ~ decommissioning the reactor facility is estimated to be l approximately $90,000, including planning and operations conducted in prepara-tion for dismantling. This cost is currently budgeted by the University of  ;

. California. .

All dismantling operations will be performed by personnel from the decom-missioning contractor, the Rocketdyne Division of Rockwell International, suc-cessor to the manufacture of the L-77 Research Reactors. This contractor was  !

l selected as a result of a competitive bidding review, including consideration of technical competence and experience. These operations will be subject to the review and concurrence of the facility manager and the UCSB Radiation Safety Officer, thus retaining full responsibility for health and safety with the licensee.

Dismantling the reactor is scheduled to begin in early January 1986, be complete in approximately 3 weeks, and a final report summarizing the decom-missioning operations and the results of the fir.a1 survey wi11.be_ completed by j January 31, 1986.

An existing approved quality assurance plan will be implemented for all transport packages containing radioactive materials. All instruments used for 2

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O radiation protection purposes are serviced and appropriately calibrated by a group within the decommissioning contractor's Quality Assurance Department.

Final survey measurements will be performed by members of the decomissioning contractor's Radiation Safety Department, with a formal procedure for qualify-ing instruments, performing survey measurements, and analyzing and interpret-ing the survey data.

The final survey will be performed by use of a sampling inspection plan designed to implement the acceptance criteria as directly as possible. The detectors to be used will include thin-window pancake GM detectors for total beta surface activity, large-area alpha scintillation detectors for total alpha surface activity, gas-flow proportional counters for both removable beta and removable alpha surface activity, and sodium iodide scintillation detec-tors for ambient exposure rate. The data will be statistically analyzed by a method routinely used by the decomissioning contractor in justifying release of decontaminated facilities for unrestricted use. (Several survey reports using this method have been reviewed and accepted by NRC Region V Office of Inspection and Enforcement, Nuclear Materials Safety and Safeguards Branch.)

1.2 FACILITY OPERATING HISTORY After operating without incident at the University of Nevada at Reno, the .

reactor was defueled and removed to its current location at UCSB. There the fuel solution was returned to the core tank and the reactor operated for in-structional purposes. No spills of fuel solution occurred during the refuel-ing operation.

The reactor was also used for activation analyses, but no significant amounts of long-lived radioisotopes were produced, and so, no contamination of l the facility resulted from these operations.

The reactor was operated intermittently at power levels less than 10 W (thermal) throughout its history. The integrated power during operaticn within the last 10 years amounts to approximately 360 W.h.

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e All radioactivity remaining after defueling the reactor and removing the startup source is associated with the reactor core tank and inner shield and the control rods. These rods will be mechanically crimped in their thimbles and disposed of with the inner shield assembly. There are no areas with hot spots of radioactivity in the reactor facility, outside of the inner shield assembly. Some areas of low-level tritium contamination exist as a result of operations with an accelerator neutron source. These will be decontaminated separately.

1.3 CURRENT RADIOLOGICAL STATUS OF FACILITY There are no areas in the facility, outside the reactor shield, where radiation or radioactivity exceeds normal background levels (other than the tritium areas). After draining the shielding water and removing the outer shield tank, radiation levels up to about 0.2 mR/h may be found. No radio-active contamination is expected. The shielding water is expected to be free of radioactivity and will be analyzed for radioactivity concentration to con-firm this prior to disposal. Provided that the activity in the wa'ter is less than 3 x 10-8 pCi/ml, the water will be disposed of by discharge to the local sanitary sewage system.

Activation of the cobalt impurity in stainless steel components of the core vessel is estimated to be less than 20 uCi at the present time. No other significant activities are expected to exist.

Because of the sealed and contained nature of the L-77 reactor, no release of radioactive material to the environment is expected. The exposure rate to the public during dismantling and transport of the reactor assembly ~ to a disposal site is negligible. There are no significant exposure pathways to the public.

1.4 DECOMMISSIONING ALTERNATIVE Because of the need for the currently occupied laboratory space for other purposes, no alternative to dismantling and decommissioning is acceptable to the licensee.

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l 1.5 DECOMMISSIONING ORGANIZATION AND RESPONSIBILITIES The decommissioning operations will be performed by the Rocketdyne Divi-sion of Rockwell International Corporation, acting as a contractor to the Uni-versity of California, Santa Barbara. These operations will be conducted under the cognizance of Professor A. Edward Profio, Departuent of Chemical and l Nuclear Engineering, as Reactor Director. All health, safety, and environmen-tal protection concerns will be subject to review and concurrence by Frank E.

Gallagher, III, UCSB Radiation Protection Officer. Ultimate responsibility and authority for proper ccmpliance with all requirements is vested in these two individuals.

l Dr. Profio reports to the Chairman of the Department of Chemical and Nuclear Engineering, who ultimately reports through the College of Engineering to the Vice-Chancellor for Administration, UCSB. D' r . Profio is a licensed Senior Reactor Operator. Mr. Gallagher reports to the Manager of Environmen-i tal Health and Safety who, in turn, reports to the Vice-Chancellor for Admin-istration, UCSB. Mr. Gallagher is a Certified Health Physicist (ABHP).

The onsite contractor staff consists of a project engineer, one or two decommissioning mechanics, and a health physicist. These personnel are sup-ported by the resources of the Engineering & Test Department and the Radia-tion & Nuclear Safety Group at Rocketdyne, in Canoga Park, California.

The project engineer reports to the manager of the System and Component Test Group within Engineering & Test, who ultimately reports to the Rocketdyne President through the Vice-President, Atomics International. The mechanics report directly to the project engineer. The health physicist reports to the Manager, Radiation & Nuclear Safety, who ultimately reports to the Rocketdyne President through the Division Director, Human Resources and Commanications.

These independent reporting paths assure objective resolution of any differ-ences at the working level.

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The project engineer is responsible for the proper technical performance of the dismantling work. The health physicist is responsible for all matters related to health, safety, and environmental protection.

The contractor staff consists of trained and qualified radiation workers, experienced in decontamination operations performed under NRC Special Nuclear Materials License 21 and State of California Radioactive Materials License 0015-70. Training includes both lecture instruction in radiation properties, hazards, and safety procedures, and practical training in decontamination, packaging, and radiation monitoring.

t Th'e University of California, Santa Barbara, is committed to a policy of maintaining radiation exposures as low as reasonably achievable. This policy is fully implemented in this dismantling project by the contractor's estab-

! lished ALARA policy and organization. In view of the protective nature of the reactor assembly and the very low exposure rates, no additional precautions beyond nomal good work practices are required.

Good work practices will be directed by both the project engineer and the j health physicist. These will include the use of survey instruments with audi-ble output; frequent surveys as work progresses; monitoring for removable radioactive contamination; personnel surveys before leaving the work area; prohibition of eating, drinking, and smoking in the work area if any removable l contamination is found or if other findings support this restriction. Both l the project engineer and the health physicist have the responsibility and the l authority to halt work for~ health and safety purposes.

UCSB management has final authority relative to health, safety, and envi-ronmental protection. ,

1.6 REGULATIONS, REGULATORY GUIDES, AND STANDARDS _ __ __ ___ _ .

The following regulations, regulatory guides, and standards are applica-ble to this decommissioning project:

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Code of Federal Regulations 4

Title 10, Part 19; " Notices, Instructions and Reports to Workers; Inspections" Title 10, Part 20; " Standards for Protection Against Radiation" Title 10, Part 71; " Packaging of Radioactive Materials for Transportation and Transportation of Radioactive Material Under Certain Conditions" Title 29, Part 1910; " General Industry Safety Orders" '

Title 49, " Transportation" U.S. NRC Regulatory Guide 1.86, " Termination of Operating Licenses for Nuclear Reactors" U.S. NRC " Guidelines for Decontamination of Facilities and Equipment

Prior to Release for Unrestricted Use or Termination of Licenses for Byproduct, Source, or Special Nuclear Material" ,

ANSI N13.12-1985, " Surface Radioactivity Guides for Materials, Equipment, and Facilities to be Released for Uncontrolled Use" ANSI /ANS-15.10-1981, " Decommissioning of Research Reactors."

4 1.7 TRAINING AND QUALIFICATIONS

The Reactor Director is a licensed Senior Reactor Operator for the UCSB L-77 reactor. The UCSB Radiation Protection Officer is a Certified Health

Physicist. Both have been trained in the subject matter required by 10 CFR 19.12. No further training is proposed.

1, The contractor project engineer has been previously licensed as a Senior Reactor Operator for an L-77 reactor. The decommissioning mechanics are expe-rienced decontamination workers. The health physicist is experienced in radi- I ation protection with a wide variety of radioactive material in diverse opera-tions. - All are trained in the subject matter required by 10 CFR 19.12. '

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, I Prior to beginning work on site, the contractor's crew will be provided j with a facility familiarization conducted by the Reactor Director, or his l designee. No further training is proposed.

In addition to training in radiation safety, the contractor's staff has been trained in industrial safety and hygiene, use of respiratory protection devices, and radiation monitoring.

Training records for UCSB personnel are maintained at UCSB. Training records for the contractor's staff are maintained at the Rocketdyne Training Department offices, 8900 De Soto Avenue, Canoga Park, C.alifornia.

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2.0 OCCUPATIONAL AND RADIATION PROTECTION PROGRAMS 2.1 RADIATION PROTECTION PROGRAM The radiation protection program to be used for this decommissioning project is an extension of the program used by the contractor under NRC Spe-cial Nuclear Material License SNM-21, the State of California Radioactive Materials License 0015-70, and under a Department of Energy prime contract.

Two types,of survey instruments will be used: one type for working sur-veys and personnel monitoring, the other for the termination survey. The .

working surveys and personnel monitoring will be performed using portable count rate survey meters such as the following, or equivalent:

Ludlum Model 12 count rate meter with Ludium 44-9 thin-window pan-cake GM for beta surface activity Ludlum'Model 12 count rate meter with Ludlum 43-5 alpha scintillator for alpha surface activity Ludlum Model 12S Micro-R Meter for ambient (gamma) radiation l

Eberline Model R0-2 ion chamber for ambient and surface dose rate.

In addition, smears for removable surface activity will be counted by use of a Nuclear Measurements Corporation ACS-77 thin-window gas-flow proportional counter automatic alpha-beta counting system.

1he termination survey instrumentation is described in Section 8.0.

In addition to radiation monitoring, personnel dosimetry is performed by use of direct-reading pocket dosimeters for exposure control guidance and by use of a dosimetry film badge service provided by R. S. Landauer, Jr. and Com-pany. All radiation workers have an NRC Form-4 on file, and all occupational radiation exposure is included in their monitoring record. Radiation workers are provided with a medical examination biennially or annually if qualified for respirator use.

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Work involving radiation exposure or potential for release of radioactive material requires the presence or availability of a health physicist. It is his responsibility to measure and. assess conditions and make recommendations to the project engineer.to assure that radiation exposures are kept ALARA and do not exceed regulatory limits.

t Both the project engineer and the health physicist have the authority to halt unsafe operations. It is the responsibility of the project engineer to avoid and prevent any unsafe operations. It is the responsibility of the health physicist to assure that adequate information is provided to the proj-ect engineer.

l The ultimate responsibility for compliance with applicable regulations resides with 'UCSB management.

Rocketdyne selects the best standard-grade commercial instruments avail-able for radiation protection purposes and therefore has not established selection criteria.

Use of radiation survey instruments for radiation protection purposes (including transportation and termination surveys) by the contractor is lim-l ited to members of the Radiation & Nuclear Safety Group. These instruments are stored in a manner to minimize the risk of damage to them. Instruments I

are calibrated by a group within the Quality Assur6nce Department on a 13-week

or sooner recall period. Each instrunent is electronically tested as appro-priate and calibrated by use of a suitable source of radiation. A documented calibration record is maintained and a dated label is affixed to the instru-ment.

Instruments used for general surveillance are qualitatively tested prior to use by the health physicist by checking the battery test and. background indications. Faulty or out-of-date instruments are withdrawn from service and sent for repair and calibration.

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Prior to leaving an area subject to radioactive contamination or easily transported sources of radiation, each person, piece of equipment, lot of material, and container of waste is subject to an appropriate survey. The work site is surveyed for removable surface contamination by smearing 100 cm2 with a small filter paper disk, counted for radioactivity in a gas-flow pro-portional counter. Large areas may be surveyed by use of a mop or towel meas-ured by use of a portable survey instrument. During dismantling, these sur-veys are performed as the work proceeds.

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Readings on pocket dosimeters are recorded daily, or more often as the conditions dictate.

Protective clothing (such as lab coats or coveralls), rubber or canvas gloves, and shoe covers are provided as needed.

2.2 INDUSTRIAL SAFETY AND HYGIENE PROGRAM ho significant amounts of any nonradiological hazardous materials are ar.ticipated in this project. No blasting will be performed and no solvents are needad. All members of the contractor's crew have been trained in routine industrial hygiene and safety practices as applied to dismantling and decon-tamination operations. Emphasis is placed on portable electrical tools, eye protection, and mobile equipment. The contractor maintains an industrial hygiene and safety staff for review and consultation, as required.

Both the project engineer and the health physicist have the authority to halt unsafe operations. It is the responbility of the project engineer to avoid and prevent any unsafe operations. It is the responsibility of the I

heal *,h physicist to assure that adequate information is provided to the proj- ,

ect engineer, by seeking home office guidance, if necessary.

Rocketdyne selects the best standard-grade commercial equipment available for industrial hygiene and safety purposes and therefore no selection criteria have been established.

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Accident prevention is practiced by reviewing operations and equipnent prior to starting, by providing both management and health physics supervi-sion, and by emphasizing the need for safe work practices. Accident response during the dismantling project will be provided by onsite (UCSB) and municipal fire-protection and emergency nudical service .

2.3 CONTRACTOR ASSISTANCE All dismantling work, packaging for disposal, and radiation surveys will be perforred by the Rocketdyne Division of Rockwell International Corporation, under contract to UCSB. Rocketdyne is the successor organization to the Energy Systems Group of Rockwell International, which .5as, for many years, performed decontamination, dismantling, and decommissioning projects in its own opera-tions and under contract to others. In addition to this general experience, this organization has decommissioned its own L-77 reactor (NRC License R-40).

Transportation of radioactive waste resulting from the dismantling opera-tions will be performed by an authorized common carrier.

To ensure that UCSB is able to effectively exercise its responsibility for compliance with all NRC requirements, frequent reviews of work will be performed by UCSB project management, including the Reactor Director and the Radiation Protection Officer. The decommissioning will also be reviewed by the UCSB Reactor Operations Cone.ittee and the Radiation Safety Committee.

l Since the contracted work is essentially the complete project, its rela-tion to the schedule is shown in Section 3.0.

2.4 COST ESTIMATE.AND FUNDING The cost of the entire project, including dismantl_ing. .. waste _ packaging, transportation, and disposal, and the termination radiation survey is esti-mated at approximately $90,000. This amount has been budgeted by the Univer-sity of California.

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3.0 DISMANTLING AND DECONTAMINATION TASKS AND SCHEDULES 3.1 TASKS The initial, preparatory task of defueling the reactor will have been completed, using currently licensed procedures, before beginning the dis-mantling.

The major dismantling tasks consist of disposal of the shield tank water; drying the core vessel; disconnection of the control rod drives, thimbles, throughtubes, and fuel and vent lines; removal of the shield tank; and packag-ing and disposal of the reactor assembly. This will be followed, after a gen-eral housecleaning, by the termination radiation survey.

3.2 SCHEDULE The entire dismantling project is scheduled to be completed in 3 weeks, with submission of the final report on approximately January 31, 1936.

3.3 TASK ANALYSES The following specific tasks have been identified:

1). Analyze and dispose of thield tank water

2) Remove rod drives and cut and crimp rod and source thimbles

3) Dry core vessel of any residual water from defueling operation

4) Disassemble reactor shield tank, cut and crimp throughtubes and i fuel and vent lines

5) Remove and package reactor assembly (intact within inner shield r

tank) for transportation to. disposal site

6) Remove all other equipment

7) Perform termination radiation survey.

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3.4 SAFE STORAGE The packaged reactor assembly will be stored in the reactor facility until it is shipped for disposal.

If the reactor facility is required for other uses before the reactor assembly can be shipped, then anotner safe storage area will be utilized.

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4.0 SAFEGUARDS AND PHYSICAL SECURITY The current NRC-approved physical security plan will continue in effect until the fuel is shipped offsite. The security plan will be teminated at that time.

No material control plan was required since no transfers of Special Nuclear Material were involved in operation of the. facility.

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5.0 RADIOLOGICAL ACCIDENT ANALYSES The reactor will have been defueled prior to the start of dismantling, and so no specific analysis is required.

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6.0 RADI0 ACTIVE MATERIALS AND WASTE MANAGEMENT l

6.1 FUEL DISPOSAL The reactor will have been defueled and the fuel packaged in approved transportation containers before dismantling begins.

6.2 RADIOACTIVE WASTE PROCESSING The only radioactive waste to be produced during this dismantling project 1 will be the reactor assembly. This will be packaged intact for disposal at an authorized site. The inner shield tank is approximately 48 in. high by 48 in.

in diameter, with a volume of 50 f t .3 The disposal package will be approxi-i 3 nately 125 ft ,

No special radwaste systems need to be implemented to meet safety and ALARA requirements. ,

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7.0 TECHNICAL AND ENVIRONMENTAL SPECIFICATIONS Because of the contained, sealed, and shielded structure of the reactor assembly, exposure rates are insignificant (less than 0.2 mR/h), and there are no releases.of radioactive material expected throughout the decommissioning project. Therefore, exposures to the decommissioning personnel and the public are ALARA and are small fractions of the appropriate limits (3000 mrem per quarter whole body occupational exposure and 500 mrem per year whole body pub-lic exposure).

The criteria for acceptable residual radioactivity for release for un-restricted use, derived from 10 CFR 20, Regulatory Guide 1.86, and recent NRC guidance, are presented below:

Surface Contamination Total Average a Total Maximum b

Removable Alpha 5000 dpm/100 cm 2 15,000 dpm/100 cm 2 1000 dpm/100 cm 2 2 2 Beta 5000 dpm/100 cm 15,000 dpm/100 cm 1000 dpm/100 cm Liquid contamination 3 x 10-8 pCi/ml Ambient radiation <5 pR/h above background a

Averaged over 1 m 2 l Averaged over 100 cn.2 There criteria apply to equipment and materials released for other uses

! at UCSB or otherwise or disposed of as ordinary scrap or waste, as well as to the remaining facility, as demonstrated by the tenninaticn radiation survey.

Survey results will be documented for all equipment and material disposed of as nonradioactive. _ _ _ _ _ _ ,

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8. 0 PROPOSED TERMINATION RADIATION SURVEY PLAN After dismantling has been completed, and all other equipment has been removed from the facility, termination radiation survey locations will be selected and identified. This will be done, in general, by establishing a virtual 3-m-square grid on the floor, walls, and ceiling. From each 3-m square (approxicately 100 f2t ), a single'l-m square will be selected that, as judged by the health physicist, is most likely to represent the highest amount of residual radioactivity within the 3-m square. The temination sur-vey measurements are made in this square. This method results in 11% of the surface area within the facility being unifomly sampled. This sampling will be increased on the floor, as necessary, to assure that at least 30 locations on the floor are tested.

In addition, each drain and any other floor penetrations will be tested.

The survey measurements to be performed consist of determination of the average alpha surface radioactivity, average beta surface radioactivity, removable alpha surface radioactivity, removable beta surface radioactivity, and the ambient ra'diation exposure rate at 1 m from the surface. If measure-ments of the average alpha and/or beta surface radioactivity indicate the presence of residual " hot-spots," a measurement of the radioactivity in a 2

100-cm area at the hot-spot location will be made.

Measurements of the average alpha and beta surface radioactivity in a 1-m square are made by using portable scalers (Ludlum Model 2220-ESG) with audible output, connected to a Ludlum Model 43-1 alpha scintillator for alpha activity and a Ludlum Model 44-9 thin-window GM for beta activity. These probes are l uniformly scanned over the surface (in close proximity) and the counts recorded I

for 5 min. Correction for detector efficiency, as measured by use of a Th'-230 source for alpha and a Tc-99 source for beta, local background, detector area, and count time results in a measure of the residual radioactivity averaged over 1m.2 Measurement of the maximum surface radioactivity averaged over 100 cm 2 within that 1 m 2is done, if warranted, by similarly scanning an area of 100 cm2 , and doing the same numerical computation.

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i Removable surface radioactivity is determined for each 1-m square by 2

smearing a 100-cm area, using Whatman 540 filter paper, and counting the resulting deposit in a Nuclear Measurements Corporation ACS-77 automatic sam-ple counter with a thin-window gas-flow proportional counter. This provides automatic and simultaneous measurement of alpha and beta radioactivity. This counting system is calibrated by use of a Th-230 alpha source and a Tc-99 beta source.

The ambient radiation exposure rate is measured by means of a Ludlum Model 2220-ESG portable scaler with audible output connected to a Ludlum Model 44-2 sodium iodide scintillator. (This is the same scintillator that is used in the Model 12S Micro-R Meter,1 in. x 1 in. ) This is calibrated in terms of counts per minute per micro-R per hour by use of a Cs-137 gama source.

i Floor drains and similar features (utility boxes or trays, etc.) that do not permit such a methodical approach will be inspected by use of portable survey instruments for alpha, beta, and gamma activity, and by smears for removable alpha and beta activity.

All sources used for calibration of survey instruments are traceable to the National Bureau of Standards.

The nominal characteristics of these instruments are presented below.

l (The lower limit of detection is calculated as the activity corresponding to three times the standard deviation of background, above background.)

Alpha surface radioactivity Ludlum Model 2220-ESG with alpha scintillator Detector area = 75 cm 2 Background = 1 cpm _ _ _ _ _ _ . . . .

Efficieny factor = 7 dpm/;pm Lower limit of detection (for 5-min scan) = 13 dpm/100 cm 2 l

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Beta surface radioactivity Ludlum Model 2220-ESG with thin-window pancake GM l 2

Detector area = 20 cm Background = 30 cpm Efficiency factor = 7 dpm/ cpm Lower limit of detection (for 5-min scan) = 257 dpm/100 cm2 Removable alpha surface radioactivity Nuclear Measurements Corporation ACS-77 with thin-window gas-flow proportional counter Background = 1 cpm Efficiency factor = 3 dpm/ cpm Lower limit of detection (for 5-min count) = 4 dpm/100 cm 2 Removable beta surface radioactivity Nuclear Measurements Corporation ACS-77 with thin-window gas-flow proportional counter Background = 30 cpm Efficiency factor = 3 dpm/ cpm Lower limit of detection (for 5-min count) = 22 dpm/100 cm2 Ambient (gama) radiation exposure rate Ludlum Model 2220-ESG with sodium iodide scintillator Background = variable from about 4 pR/h to 20 pR/h Efficiency factor = 0.0038 pR/h/ cpm Lower limit of detection (for 5-min count) = 0.3 pR/h above background In all cases, the actual values for background and efficiency factor are deter-mined for each instrument.

l The data obtained are analyzed by use of a computer program that takes the fundamental instrumnent reading and performs the necessary calculations to pro-2 duce the derived result, either dpm/100 cm or pR/h, thus minimizing trans-4 cription and' arithmetic errors. The results are then interpreted in a cumula-tive probability distribution that permits comparison with the acceptance limit in a manner analogous to sampling inspection by variables as described in MIL-STD-414. The inspection test is calculated for a consumer risk of 10% at a l

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lot-tolerance-percent-defective of 10%. The graphical display provided by the computer program clearly shows any results indicating contaminated locations, well below the acceptance level. This display also shows calculated uncertain-ties in the results, based on counting statistics and provides a means for checking the consistency and freedom from error of the input data.

Instrument qualification sheets are prepared for each instrument, gener-ally daily. These, and the fundamental data sheets are reviewed and compared with the analytical results to confirm the survey quality.

A summary report of the survey results is prepared for submission to NRC to support a request for termination of the license.

All survey documents are retained until after concurrence by NRC that the facility is acceptable for release for unrestricted use.

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ENVIRONMENTAL REPORT IN SUPPORT OF THE DECOMMISSIONING PLAN FOR THE L-77 RESEARCH REACTOR UNIVERSITY OF CALIFORNIA SANTA BARBARA i

Prepared for UCSB by Rocketdyne Division Rockwell International Corporation Canoga Park, California.

August 5, 1985 t

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1.0 INTRODUCTION

It is planned to decommission the L-77 research reactor facility at the University of California, Santa Barbara, by dismantlement and disposal of the reactor and release the facility for unrestricted use. Estimates of radiation exposure and releases of radioactive material during and after completion of the decommissioning project show the environmental impact to be insignificant.

2.0 COLLECTIVE DOSE EQUIVALENT TO WORKERS The collective dose equivalent to workers who are occupationally exposed to radiation during the dismantling operations is expected to be less than 0.045 person-rem above background.

3.0 PUBLIC EXPCSURE TO RADI0 ACTIVE EFFLUENTS No radioactive effluents are released to the public during the disman-tling operations.

4.0 PUBLIC EXPOSURE FOLLOWING LICENSE TERMINATION The facility will be decontaminated to residual radioactivity levels below those presented in U.S. NRC Regulatory Guide .l.86. The ambient radia-tion exoosure rate will be less than 5 uR/h above background. Exposure of the public will be insignificant.

5. 0 CONCLUSION Exposures anticipated due to the planned action are small fractions of regulatory , guidelines. The environmental impact of this action is insignificant.

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