ML20042F044

Responds to 890620 Inquiry Re Licensee Decommissioning of Plant.Instruments Used by UCLA for Releasing Matls for Unrestricted Use Appropriate

ML20042F044
Person / Time
Site:	05000142
Issue date:	04/26/1990
From:	Weiss S Office of Nuclear Reactor Regulation
To:	Hirsch D FEDERATION OF AMERICAN SCIENTISTS
References
NUDOCS 9005070139
Download: ML20042F044 (4)

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' April 26, 1990

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Docket'No. 50-142 L

L Mr.' Daniel Hirsch l

c/o Federation of American Scientists 307 Massachusetts Avenue, N.E.

t Washington, D.C.

20002

SUBJECT:

. INQUIRY CONCERNING UCLA DECOMMISSIONING l

During'a conference call on June 20' 1989 concerning the decomissioning of 'the UCLA Research Reactor, you asked for.a response to three questions about radia-3 tion and contamination measurements made'during Phase I of the decomissioning..

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(1) 'How-does UCLA's release level of net a0 cpm relite-to the dpm/100'cm values'given in Regulatory Guide 1.86, " Termination of Operating Licenses for Nuclear Reactors?"

This matter is described in NRC Inspection Report No. 50-142/89-01, Paragraph 5.

2 UCLA used 1000 dpm/100-cm estimatedthesensitiveareaofthedetectortobe30cmforestablishingtheirrele criteria. They _ _

t limit to 200 dpm per detector area (1000.dpm/100 cm (200dpm/20'cm).'The 2 pi efficiency of the detector was determined for Tc-99' betes (average energy.

L of 85' kev) using sources traceable to the National Institute of Standards and Technology (NIST). This efficiency was-determined to be 20%; thus their release I:

L criteria was found to be 20% of 200 dpm or 40 cpm perl detector area.

The manufacturer's product literature states that the' diameter of the detector' 2

is 4.4 cm which would indicate an area'of 15.2 cm. This same literature also indicates that for Sr-90 the. efficiency ig 65%. With' these values, UCLA release criteria fgr Sr-90 becomes 405 dpm/100 cm, and for beta-gama emitters 1316 dpm/100 cm (usingtheTc-99 efficiency).

These values are acceptable since'they met the average and maximum contamination levels for beta-gama emitters -and Sr-90;from Table 1 of Regulatory Guide 1.86.

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For removable contamination, UCLA conducted separate surveys capable of detec-It ting levels below the Sr-90. removable contamination levels specified in Table 1 i

l of RG 1.86.

Further, it can be demonstrated that I-129, a long lived fission product with more restrictive limits, is not present above its limits.

Based on the yield p

offisgionproducts,'Cs-137productionlevel(activity / fission)isa_ factor?of 5 x 10 greater than that for I-129. For I-12 ingitsmostconservativelimit(20'dpm/100cm)tobepresentatlevels: exceed-removable).-thecorrespondigg 6

level of Cs-137 activity would have been in the range of 9 x 10 dpm/100 cm,

which exceeds the limit for Cs-137 by a factor of 9,000. The measurements made by UCLA for materials released for unrestricted use did'not identify such levels 1

of activity.

It is therefore, a logical conclusion that 1-129 is not present at significant levels.

,9005070139900426m,

a April 26,1990 Mh Daniel Hirsch,

(2) Were the survey instruments used by UCLA appropriate (i.e., of sufficient

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sensitivity) for detection of contamination and radiation fields to release materials for unrestricted use?

The instruments used by UCLA for releasing materials for unrestricted use were appropriate.

UCLA used a Ludlum Model 3 with a shielded Geiger-Muller thin window " pancake" detector, model 44-40, for measuring total surface contamination.

For a discussion on-its sensitivity, see the res)onse to question 1.

For removable contamination, UCLA used an Eberline beta counter Model BC-4. This instrument has sufficient sensitivity to detect C-14 (average beta energy of 49 kev) at 15% efficiency.

For radiation levels, UCLA used a Ludlum model 19 Micro-R-Meter with a NaI(T1) detector. Although this is not a true dose rate instrument, Micro-R-Meters are ideal for identifying low levels of gama contamination. All of these instruments are in comon

-l use throughout the nuclear industry. The instruments were calibrated against j

standards traceable to NIST.

I (3) It appears that non-removable contamination measurements were. not performed for the reactor shielding blocks that were released for unrestricted use. Was the survey procedure and survey instruments used appropriate?

y UCLA has stated that surveys for non-removable contamination were performed on-the reactor shielding blocks that were released for unrestricted use. As i

noted in the inspection report, the quality of the records maintained needed to be improved. Although not included in the records titled " shield block

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survey form," UCLA believes that surveys for non-removable contamination were conducted when the blocks were first surveyed after removal from the reactor room. However, UCLA has not been able to locate records of these surveys.

In order to document-that the criterion for non-removable contamination was met UCLA has located the concrete blocks that were released for unrestricted use and conducted additional surveys of the blocks.

UCLA has informed Region.V in a letter dated January 11, 1990, + hat-results of the surveys of the surfaces document that the criterion for beta-gama emitters has been met. The survey-instruments'used were appropriate, as discussed in the response to question 2.

If you have any Adams, Jr., at (questions concerning this matter,.please contact Alexander 301)492-1121.

l Sincerely, Original signed by:

Seymour H. Weiss, Director Non-Power Reactor, Decomissioning and Environmental Project Directorate Division of Reactor Projects --III, I

IV,.Y and Special Projects.

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Mr. Daniel Hirsch -

(2) Were the survey instruments used by UCLA appropriate (i.e., of sufficient sensitivity)fordetectionofcontaminationandradiationfieldsto release materials for unrestricted-use?

The instruments used by,UCLA for releasing materials for unrestricted use were appropriate. UCLA used a Ludlum Model 3 with a shielded Geiger-Muller thin window " pancake" detector, model'44-40, for measuring total surface-contamination.

For a discussion on its sensitivity, see the' response to question 1..

For removable contamination, UCLA used an Eberline beta counter Model BC-4. This. instrument has' sufficient sensitivity to detect C-14 (average beta _ energy of 49 kev) at 15% efficienc i

used a Ludlum model 19 Micro-R-Meter with a Nal(y. -For radiation-levels, UCLA T1). detector. Although this.

is not a true dose rate instrument, Micro-R-Meters are ideal for identifying low levels of ganna contamination. All of these instruments are in common use throughout the nuclear industry. The instruments here calibrated against standards traceable to NIST.

(3) It appears that non-removable contamination measurements were not i

performed for the reactor shielding blocks that were released for.

unrestricted use. Was the survey procedure and survey instruments used appropriate?

UCLA has stated that surveys for non-removable contamination were performed on the reactor shielding blocks that were released for unrestricted use. As noted in the inspection report, the quality of the records maintained needed to be improved. Although.not. included in the records titled " shield block survey form," UCLA believes that surveys for non-removable contamination were conducted when the blocks were first surveyed after removal.from the reactor room. However, UCLA has not been able to locate records of these surveys.

In order to document that the criterion for non-removable contamination was met 3

UCLA has located the concrete blocks that were released for unrestricted use and conducted additional. surveys of the blocks. UCLA has informed Region V in a letter dated January 11, 1990, that=results of the' surveys of the surfaces document that the criterion for beta-gamma emitters has been met. The survey instruments used were appropriate, as discussed in the response to question 2.

If you have any questions concerning this matter, please contact Alexander Adams, Jr., at (301) 492-1121.

Sincerely,

%ws 4 ::9 Sey{mourH. Weiss, Director e

l Non-Power Reactor, Decommissioning and 1

(

Environmental Project Directorate l

Division of Reactor Projects - III, l

IV, Y and Special Projects Office of Nuclear Reactor Regulation cc:

See next page

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University of California Docket No. 50-142 t

at Los Angeles 1

cc:-

Mr. Neil C. Ostrander, Manager Dean Hansell Nuclear Engineering Laboratory 302 South Mansfield Avenue School of Engineering and Los Angeles, California 90036 Applied Science j

University of California Committee To Bridge The Gap j

at Los-Angeles 1637 Butler Avenue f203 l

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Los. Angeles, California 90024 Los Angeles, California '90024 Mr.' James R. Heelan

' Mr. John Bay -

L Director, Society Services 1022 Peralta Street American Nuclear Society Albany, California 94706 555 N. Kensington Avenue' La Grange Park, Illinois 00525 Roger Kohn, Esq..

- 524 11th Street California Department of Health Manhattan Beach, California 60266 ATTN: Chief. Environmental

Radiation Control Unit Robert M. Meyers Radiological Health Section City Attorney 714 P Street, Room 4981 Lynn Na11 boff Sacramento, California-95814

' Deputy City Attorney

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1685 Main Street, Room 310 Mr. Daniel Hirsch Santa Monica, California 90401

% Federation of American Scientists 307 Massachusetts Avenue, N.E.

i Washington, D.C.

20002 l

William H. Cormier, Esq.

L-Office of Administrative Vice Chancellor University of California 405 Hilgard Avenue l

Los Angeles, California-90024 Christine Helwick, Esq.

l Glen R. Woods;'Esq.

j, Office of General Counsel-590 University Hall' 2200 University Avenue l

Berkeley, California 94720 1

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