ML20236U595

Partially Withheld Response to 860604 Questions Re Impact of Changes in Release Criteria for Irradiated Stones.Approach Accommodates Variable Background by Determination of Overall Instrument Background & Variation

ML20236U595
Person / Time
Site:	University of Missouri-Columbia
Issue date:	06/13/1986
From:	Brugger R MISSOURI, UNIV. OF, COLUMBIA, MO
To:	Axelson W NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML20236U580	List: ML20236U579 ML20236U593 ML20236U595
References
FOIA-87-500 NUDOCS 8712030180
Download: ML20236U595 (4)

Text

, ........, ,

Research Reactor Facihty

, -- _ i 9 colum6m. maneew.atst Telephone (314) W411  ;

June 13,1986

" pupDV 'C'-M l es u  !

n m Willf as Anelsen kb g d

Nuclear Regulatory Commission

• Region !!! ,

799 Roosevelt 81df 4 l Glen Ellyn, IL 60137 i

/Y/

Dear W 1 son:

This letter is being sent to answer geestfons yes asked durfog our visit to your office on June 4th and durlag our subsequent phone conversatfoes.

- y We would appreciate the following informatfoe beleg handled as proprietary.

Impact of the Channes in Release criteria for Irradiated Stones The IslRR, has been involved sface 1981 f a develeplag the technology of 1 frradiattag tapaz with fast neutrees to introduce colar centers and produce dark blee stones. .Sech development fits the charter of IllRR, that is, to support research education and service esteg mostrens, genen rays and  ;

radiofsetepes. The tapet developeset has presented staffe faculty and '

students with the apportuelty to condect resterek (f.e., explate the celer centers), engineerfes development (f.e., urt eeftsare for rebetics) and j technoley development (f.e., learetag and me federal shipping '

regulattees). It has been an eacelleet trefales project havfag many technical challeeges, and the rewards of seefog solettens used to feprove productfen.

As la mit techselegy develope $$ 'fiIt forestation of topaz Es*

developed but the rate of frradiatten and relans tones has been -

_ 1acreasf 8712030100 871130 -

FOIA EDWARDS87-500 PDR 3.

9PDR COLUMBIA KANSAS CITY ROLLA en aquet apponwerww amen ST. LOUIS a 4.

i Page t William Axelson ,

June 13,1986 l I

1 The income from the irradiation of topas all restles with the IRRR; none .!

is transferred elsewhere 1a the university. The reters goes to help suppert ,

reactor operations, development of techseleafes, researth, stedsets and the i I

sporade of the MNE. bestricted reture will hurt all of these het the mest severe tapact will be en the upgrade. - The upgrade to 3558 and a es14 source and guide hall is projected to cost $15,000,000, and we were anticipating the return from tapar would be a significant initial source of funds for this upgrade, gperistion of the Countine Svstas Release Criteria introducties The Mmt Tapa Scanner (Unit 1) consists of up to 32, F ty F, ta! well 1 detectors uhich are controlled by a computer program capable et sorting goe stones according to the counts recorded by the slagle chamael analyzers which are coupled to each mal detector. Normalisatfee to a melt uelpt is allowed for by the system.

The objective of the instrument is to provide a means for detecting radioactivity la sus stones that have been feradiated la a thermal nostron i shielded fact 11tr and sortleg out of these stones chich are met significantly i different free background.

Determinaties of lastrouset teckerosed Iteen (fbe) rach mal detector la the festresset is shielded such that the average  !

backgrosed has hees redeced to apprestattely IN of asteret tempeand. At  ;

this level the lastrueret teckground fs apprestaately les to M aps. The i source of this serfetten is Wefeld. Ambient backgreemd verfes dependf as en  !

ether esportseets betag coedseted la the general area. Estee serles la the  ;

detectors ned asserlated electronics. ,

Together these sarfattaas la background are larger than that espected from counting statistics alone. In order to estimate hockgreemd and 1ts variability se see de the following:

/ We detereise en instrument background at least esos per day.

Inicially and untti such time that the rendes vertatten la instresset heckground is determined, we enke als esenerement en a l sore fregeset basis. At this time, the measurement ts being done

/ every to hears for those perleds that the festrusset is la producties use.

The testrument background mean (ibs) is defleed as the summation of individen1 detector means divided by the neder of detectors on line l (na1-12).  ;

i 5

I

__ _ _ __ _ - -__ L

Page 3 Nf111am Axelson June 13, 19N Determination of Instrement Backereemd Standard Deviation (fbs)-

The instrument background standard deviation average (fbs) is deff as the square root of the sus of the averspe warfance within a detectar ( )

and the vsrfance between detectors (sb 8 s and is given by:

l fbs = /s w2 + sb*

l The 9M confidence interval [CI(.99)] is defined as that range la causts required to faclude 995 of the possible fastrument background counts gives the l 1

standard deviation described la the famediately proceeding section. 53(.99)  !

wt11 he deteralmed us1og the students *** test us1mg the two-tatled" t i tables.  ;

I CI(.99) = (tra.11.ee) - (fbs) fK i

Appitcation of Confidence Interval

/ A gee stone sample is counted for a period of 30 seconds yieldfag C l

counts. The sull lypothesis (Re) states that C is not different from I bactyround. Ilo is accepted if C falls within the individual channel i bac,kground (fch) i CI(.99) and the stone is released as

• men-radienstise'. If C does not fall within feb e CI(.99), the to is rejected and the stmas fs held {

for counting again later at the Wtt.

Enample The fellerfes example portales to data collected on June 6,1906 estas a 5-detector lastrument configuraties, j e=5 ty=123cpe i sv = 117  !

sh8 = 2014 i its = 46 l t(n-1).99 = 4.604 / % T./u j CI(.99) = (4.604)(46) = 95 "I (5

For a gee stone counted la channel 1, where the ich is 164 cpe, No is accepted if the count rate were less than 259 cpe. For channels 2, 3. 4 and 5, the ich's are 68,170, 89 and 124 which lead to upper boends of 163. 265 184 and 219 cpe respectively.

Page 4 ilfilfan Axelson June 13, 1986 In sammary, our approach is to accomodate sur verfable hockgreemd by deterstaation af the overall instrument background and its variation.- We then apply this variation, la the form of a confidence feterval, to the individual channels heleg used to count stones. -

If we can supply you with further information in this matter, please do not hesitate to call upon us.  !

1 51 y, 7

h et n. srepper Directar RMB/dd l

e

1 GA hhrologes i -

GA Technologies Inc.

l PQ BOX 85606

{ $AN DIEGO cal #QONIA 92138 (619; 4W3000 Law Department July 30, 1987

'IEEDOM OF INFORMATION

?

\

Regional Administrator, Region III hb$-57-30o i

U. S. Nuclear Regulatory Conunission 799 Roosevelt. Road M h[kd Glen Ellyn, Illinois 60137

Dear Sirs:

}_,,_ __ _

This is a request under the Freedom of Information Act, as amended.

In a generic letter 86-11 dated June 25, 1986 the Commission prohibited the distribution of irradiated materi-als, licensedeven with low levels of induced radioactivity, to un-persons.

from J. W. According to a letter to GA Technologies N. Hickey dated November 10, 1986, and subsequent discussions, the University of Missouri has been allowed to continue distribution of irradiated gemstones under certain i

specific conditions.

GA Technologies requests a copy of any and all docu-ments or files, Region III, pertaining to the review and approval by

./ the University of Missouri,for the distribution including of irradiated but not limited to gemstones by (a) all minutes of reviews conducted by Region III and by NRC headquarters especially if joint inspections / reviews were, conducted; (b) copy of all sketches and descriptions of count-ing or assay equipment, lower levels of detec-tion, and its use as approved by Region III for the University of Missouri, for assay prior to '

the release of irradiated gemstones; (c) copy of all pertinent material on calibration of the University of Missouri counting / assay equip-ment; d h/ [

n\W < wos _ _ _ _ _ . _ _ _

y .-

o, << '

/

w Il ,

tJion Administrator, Region III  !

g @U. S. Nuclear Regulatory Commission t

'! Page 2 July 30, 1987 (d) an accurate statement of the effective radiation levels approved by Region III for the release of irradiated material to be distributed.' by the University of Missouri.

Thank you for your prompt attention to.the above request.

Very truly yours, i es R. Edwards  :!

General Counsel.& Secretary  ;

l JRE:lre ec: William L. Whittemore l

1 M M M

\

\

\

__