ML20205G216

Ack Receipt of Application for Renewal of License SNM-179. W/Record of 850116 Telcon

ML20205G216
Person / Time
Site:	07000192
Issue date:	02/18/1988
From:	Whiston P NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
To:	Jackie Jones MICHIGAN, UNIV. OF, ANN ARBOR, MI
Shared Package
ML20205G163	List: ML20205G162 ML20205G191 ML20205G212 ML20205G216 ML20205G243
References
384800, 77940, NUDOCS 8810280212
Download: ML20205G216 (3)

Text

. f FEB 181988 University of Michigan License No. SNM-179 Radiation Control Service Control No. 384800 ATTN: John D. Jones, Director 1101 North University Buildgin Ann Arbor, MI 48109 Gentlemen:

SUBJECT:

LICENSE RENEWAL APPLICW,10N This is to acknowledge receipt of your application for renewal of the material (s) license identified above, Your application is deemed timely filed, and accordingly, the license will not expire until final action has been taken by this office.

Any correspondence regarding the renewal application should reference the control number specified and your license number.

Sincerely, Patricia J. Whiston Materials Licensing Section 12 800bOS 70 PNV

$$$ f.

SNM-017 I55

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i TIVE CONVERSATION RECORD i 2l55EDATE I//L,/h*

0 VISIT O CONFERENCE LEPHONE _ _ _

O IN OMING ""*.*!"' '."I-Locat.on of Visit / Conference: , , UTGOING NAME OF PERSON (S) CONTACTED OR IN CONTACT O R GAN12 A TIO N (Omce. deot , bureau, i TELEPt4CNE NO WI YOU etc ) p }l))

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, ,U The University of Michigan Radiation Control Service " ~

1101 North University Building I'ECEIVED UY Lf MS Hay @- 0 tc:..lf}$ &, f f ,,

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Materials Lictnsing Section 799 Roosevelt Road Glenn Ellyn, IL 60137 Re Amendment License No. SNM-179 Gentlemen This is an application to amend SNM-179 to allow possession and use of an Americium-243 plated source. The source strength will be up to 20 microcuries (100 micrograms). The source will be used in conjunction with the Department of Energy sponsored project cross section measurements.

The Americiu a-243 in convenient chemical form will be deposited on a =ct:1 Lacking approximately three centimeters in diameter and one millimeter thick. The active deposit will be restricted to a diameter of approximately five millimeters. This will result in a sufficiently large outer rim for convenient handling with tweezers.

The authorized user also plans to investigate the possibility of evaporating a thin layer of gold on to the source to reduce the possibility of loss of material from the active surface.

The source will be used as a gamma ray activity standard with its activity accurately determined by solid angle alpha particle counting. Handling precautions appropriate for s plated alpha source will be observed. When not in use the source will be housed in a plastic container and stored in a stainless steel glovebox maintained at a reduced pressure with respect to the room air. At the time of use the source will be transfered from storage to the experimental area. Personnel involved will wear gloves, film badges and finger tabs. The source will be returned to storage after each measurement. Smears for surface contamination willfb6. O g g y E. O carried out under the supervision of Radiation Control Service staff following each handling of the source, h OW6 0531 DU 4 8W h

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U.S. NRC Pace 2 1

I The source will be used in the neutron cross section laboratory at I the Phoenix Hemorial 1.aboratory. There is a slim possibility that I the source may be used temporarily at the neutron bay located in the Naval Architecture and Marine Engineering Building. We will still include that building as an authorized area of use. RCS will transfer the source between the buildings and the handling l

i procedures would be the same in either facility.

I Yours truly,

[&km ) &~

Arthur J. Sol 1. Director AJS/dl

' MITIE NC.

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) RADIATION CONTROL SERVICE 1205 NORTH UNfVER$17Y AVENUE k 1101 NORTH UNIVERSITY BUILDING ANN ARBOR, MICHICAN 48109 013)764-4420 i ARTHUR l MXARI ono.

December 4, 1984 '

RECEWE0 0f LIMF  !

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U.S. Nuclear Regulatory Commission y tot. M .

Region III g y , , , , , , W, , . . . .  !

Radioisotopes Licensing Section 799 Roosevelt Road g,

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• i Glenn Ellyn, ILL 60137 .g M M u

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Gentlemen 3; 3 E M This letter is to request an amendment to License NN SNM-179 to ( A) permit the ,

use of more than one source at a time in the laboratories and (B) permit the ,

acquisition of 50 milligrams (35 microcuries) of Np-237 in the form of an oxide powder.

At present our license covers possession of five Plutonium-Beryllium neutron ,

sources. We specified that four of the five sources will be kept "permanently"  !

I sto ed in Phoenix Memorial Laboratory, and the fifth source would be in use.

We request that the following buildings / rooms be added to the license for the storage and proposed use of Pu-Be neutron sources:

1. The Neutron Bay /D-T neutron source room in the Naval Architecture and Marine Engineering Building. This room formerly housed a cyclotron at the University and presently houses a neutron generator. The Pu-Be source will be used for neutron detector testing and calibration.

I When not in use the Pu-Be source will be stored in the storage port i located underground in the concrete wall of the Neutron Bay. The port will be locked and the main entrance also locked with limited access.  ;

2. Cooley Building /156 Measurements Laboratory. The Pu-Be source would also be used for neutron detector testing and calibration.

A locked wax filled steel drum will be used in the 156 Cooley Measurements Laboratory for the storage of Pu-Be sources. This room is locked when lab .

sections are not in session. l C. Phoenix Memorial Laboratory. RECElyED At the present time it is anticipated that the three rensining s N  !

will remain in the Phoenix Memorial Laboratory unless a temporary neej 0193.g  !

arises at other locations, e.g., Neutron Bay area. The sources JI g g l transported as necessary between buildings by Radiation Control ControT' N  !

Service in a wax filled steel shielding drum capable of holding all five sources, r

950325000'A 850307 ffy go'NTROL NO. 7 7 0 4 0 agc to BM REG 3 LIC30 SNM-0179 PDR ,

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- Amendment . Page 2 The sources may be used in laboratories which are assigned to the Nuclear Engineering Department and located in the Phoenix Hemorial Laboratory building.

The second part of this amendment request is to obtain permission to acquire and use 50 milligrams (about 35 microcuries) of Np-237 in the form of the oxide powder. Professor Knoll plans to use the Np-237 as a tracer in an experiment that will involve chenical .teparation of small quantities of Np-239 from U-238.

No more than five milligrams of Np-237 will be used in any one experiment.

Np-237 is used as an isotope tracer in the chemical separation in the daughter element of neutron-capture reaction of U-238, i.e., Np-239, so that accurate separation yield can be determined. Separation procedures will be done in a glovebox at the Phoenix Memorial Laboratory. The procedures to be followed are very similar to those already used in an earlier experiment on thorium-capture and published in Nuclear Science anj Engineering: 88, 123-128 (1984) under the title, "Absolute Measurement of the Cross Section for 23-kev Neutron Activation of Thorium." A reprint of the article is enclosed which details the separation process used in that particular experiment and which will serve as a model for the new efforts. No problems of contamination were encountered in the referenced study.

If there are any questions please contact me.

Yours truly, ht</ m [ by Arthur J. Solari AJS/dl eno C6i!Tnbt.m 7 7 9 4 C L- . _ _ _ _ _ _ _ _ _ _ _ _ . _ . ,_,_

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} j Absolute Measurement of the Cross section for j

)* 23 kev Neutron Activation of Thorium h

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i George T. Ilaldwin' and Glenn F. Knoll I

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o (Iniversity of Alichipn. Departrernt of Nuclear Englntering h :.

1 Ann Arbor, blichipn 43109 I ii

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Received December i9, J933 i Accepted Sfarch 2,1934 3 >l ll

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s Abstruct- A bsolute measurement of the thorium radiative capture cross section has been made using -

entimony-berythum photoneutrons a ud an cctivation method. The average ofIwo determinations is t

{ 606 mb near 23 keVneutron energy uith a 3.2% estimatederrorfrom cilsources. This va!ur is ~10%

f .',

higher than those reportedfrom recent measurements employing iron fdtered neutron beams.

j h- Mesure absolue de la section effleace d' activation du thorium pour des neutrons de 23 lev Risumi-La mesure absolue de 1.t section efficace de capture radiative du thorium a it/faite en utilisant des photoneutrons ima tant de la r/ action antimoinr4rry!!!um et une m/:hode d' activation.

La mo> rnne de deur mesures est de 606 mb pour des neutrons cya=tt une inergie voisine de 23 ke V, Terreur due b toutes les sources / tant estimle b 3.2%. Cette valeur est en viron 10% plus flerle que celles obtenues ricemment b partir de mesures emplojant desfaisceaux de neutrons (dtr/s cufer. .

Abelete Wirkngsqu rschnlit Mes urgrn bei S L:V Neutroneukt%I.rt.cz von 1.sorium Zusammenfassung- Absolute blessungen von Thoriumabsorptionsquerschnitten nurden durch l

Anuendung von Antimon-Berylllum-Photorteutronen s:mtder Aktivierungsmethoste durchgefuhrt. Der Durchschnitt v.rier Bestimmungtn betrEst 605 mb bei 23-AeVNeutronenenergie mit einem durch. .Y' schnittlichen l'ch!er von 3.2% cus cllen Que!!rn. Dieser it'ert f.egt ungrfahr 10% ube? dem der neu-  ;

cren hiessungen bei l'erwendung von Enen filtrierten Neutronenstrah!rn. >e i,

1 INTRODUCTION The conclusions reported in those evaluations have  ;

indicated a high priority need for additional measure- .

Radiative neutron capture in thorium results in ments of the thorium capture cross section for fast esentual formation of the fissile isotope 3 "U. For this neutrons. il renon, the associated reaction cross section is of key Facilities have been des cloped at the Unisersity of j importance in fast reactor design calculations based on Michigan (UM) for making absolute measurements of g.

a Th/ 2"U fuel cycle. Thi: alternatise (thorium) fuel actinide fission cross sections using five photoneutron cycle has received renewed attention in response to sources.* Of these sources, only antimony ber)llium concerns about nuclear fuel cycle safeguards and ura- could provide a sufficient neutrou fluence to allow the nium asailability, and has motivated recent reesaina- esperimental approach described in this paper. Mea-tions of nuclear crososection data for thorium.8 surements were therefore made only with this source.

The conceptual basis for absolute measurement

• presci t .Jdress: Ssndia National Labora:ories. Disi- derives from the defining equation for the reaction son 12U, Albuquerque, New Mexico 871!5. cross section, namely, .{

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.' 23

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124 BA1.DWIN cnd KNOLL ( ", ,

R EXPERIMENTAL h1ETilOD

'

• N+ ' . Nejttron Source where The spherical source consisted of a core of metallic R = capture reaction rate (s-8) antimony,1.5 cm in radius, surrounded by a 3 mm.

' N a total number of '"Th target nuclel thick beryllium shell and a 3 mm thick a!"minum outer casing. It was activated by irradiation fer 20

+ = scalar neutron flux (cm-8.s-8). days in a flat flux of ~10" cm-8 s in the 2 blW The value of each quantity is measured absolutely; the pool-type Ford Nuclear Reactor. The source strength anese bath method,i.e., by cross section a (cm ) then follows directly, 3

was calibrated by the The reaction rate R is determined indirectly by comparing the saturated 8 manghin activity induced b antimony-beryllium source with that induced by a lab-measuring the amount of the 8"Pa daughter Isotope oratory reference 2"Cf source. The anCf source had activity present in a thorium target after a prescribed been previously calibrated against the U.S. National irradiation period. From the differential equations Bureau of Standards (NBS) 11 secondary neutron stan.

associated with the decay sequence dard.8 Small corrections (<2%) were made lo ac-

1. ~ #- 2

. c unt for detector counting losses, source decay, 2"Th(n, y)2"Th sus-2Ne 233p3v e a-2EiT "U ' solution mixing, and neutron losses (including source self absorption) hianganese bath calibrations were one obtains the solution made once before and once following two target expo. ,

sure runs. Interpolation of the source strength during I 'np(t i tz)(Ar- A.slexp(Arta)- the target exposures assumed a photoneutron source a = N+a , exp(- A,ti ) - exp(-Arti ) . half life' of 60.20 ( A0.1%) days. Results are given in Table 1.

llere, the expression in brackets is just the reaction '

2 rate, quan'itatively related to the number np of np, N 'l"* D'###

• nuclel present at time 12 after an irradiation of dura.

tion t l Apis the 2nPa decay constant. A photoneu. Samples of natural thorium metal were obtained .

i tron flux of the form f(!) = toexp(~K,t) is assumed, from the Oak Ridge National Laboratory as flat sheets where A,is the "'Sb decay constant. measuring 25.13 x 12.00 x 0.05 cm and weighing TABLEI -

The Antimony-Beryllium Source Strength

.=

hicatured Extrapolated 8"Cf Reference Strength Saturated Acthity Source Strength Date and Time of Calibration (n/s) Ratio (n/s)

February 11, 1981 2.729 x 10' 7.803 2.129 x 10' (17:12) (20.73re) (10.84re)

April 11,1931 2.616 x 10' 4.106 1.074 x 10' (13:00) (2 0.75%) (10.88te)

Extrapolated Based on rint Based on Second Weighted Aserase Calibration Calibration Strength Date and Time of Run Start (nh) (n/s) (n/s)

February 17, 1981 2.003 x 10' t,989 x 10' l.997 x 10' (00;l6) ( A 0.84re) (i0.88re) (* 0.9fe) 1.567 x 10' l.556 x 10' l.562 x 10' h! arch 10.1931 (03:34) (i0.84re) (t 0.88re) (10.9re )

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i NEUTRON ACTIVAllON OF Ti!ORIUM 125 l-l'o

-170 g. The number of "Th 2 nuclei in each sample scalar Dux at the target per unit source strength, deter. ?j was determined to within an uncertainty of 0.5%, by mined by calculation. Only the spatial average of the H weighing and using the supplier's value for the sample aux per unit source strength is of interest, because the f purity (93.5

• 0.5 mass percent thorium, measured by method that is used after the irradiation to measure ${

g V chemical analysis'). the induced 2"Pa activity depends only on its total p amount, not its spatial distribution. i/

I For each target activation, a single thorium sheet was bent into an S cm l.d. x 12-crn.high cylinder A Monte Carlo method' was used for the Dux per f

enclosed by an outer 1-mm. thick aluminum casing, unit source strength calculation in order to accurately  :";

The source sphere was positioned at the center of the represent the source / target geometry, the complex target cylinder (see Fig.1). A cadmium-lined $5 gal polar angle distribution of emitted source neutrons, h il

(

steel drum isolated the assembly from room scattered and the effects of scattering within the source, target, and structural materials. A complete representation of  !

r (thermal) neutrons, i neutron scattering and absorption within the materlats of the source itself was ttsed to derive the energy flux Dc/temirratiori spectrum of the emergent neutrons (see Fig. 2) and The neutron Dux was obtained as the product of their angular distribution. Neutron interactions in the the (time-dependent) source strength, measured by the target and support structures were modeled using

,3 manganese bath technique, and the (time independent) one energy group and assumed isotropic scattering.

The Oux per unit source strength was derived as the l accumulated total track length of neutrons within the target divided by the target volume and by the l number of input neutrons.The net effect of scattering

!  % '-a'*-) was obsened to increase the Hux by almost 6% ovei i FM 079 that obtained when no scattering was assumed. Most of the Hux increase resulted from scattering within k the thorium sheet itself (4% effect). A value of t) lsA 3.61 x 10-3 (+0.9%) em-2 3-i was obtained for the

, %I) aserage scalar flux per unit source strength.

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" 0.10 Fig.1.1%perimental apparatus. A sheet of naturs; #

thorium metal ( A) w as fitted inside aluminum c>linder (D) anJ beld in place by the top and tutom end rinn (C,1)).

0 --

T his suembled target unit w as then slipped onto the bot- 20 33 0 10 tom section of the bran saurce well (I ). Croup:eee (1 ) sup.

ported the photoneutron source (G)indJe the souree well.

ficutro, energy Dev) certcred with respect to the tartet. Ti.e source wc!! sus-penJed the noembly in the center of a cadmium-tmed l e. 2. Antimony bo,ltium photoneutron enerty dis.

tribut: an cal:al.ned by Monte Carla simulation.

55 tal drum.

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126 O BAl.DWIN and KNOT.t.

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Isolation o/ *Pa " Pa act'vity at the UM by counting the' 312 key I

v nma ray activity and using 38.6 g'amma rays per Two thorium targets were irradiated in si .w:- !O decays for the branching ratlo. ilowever, the each for ~2 weeks. A chemical procedure' o ',,1 1. .wr method was limited by the accuracy to whkh the after irradiation to isolate 2 "Pa. First, the .% ur absolute Ge(LI) detector ef0ciency was measured, was dissolved in -1 f of hydrochloric acid conwming All gamma ray counting made use of a $$ cm2 a trace amount of liF. Following dissolution, the closed-end coaxial Ge(LI) detector in the prewnee of fluoride ion was complexed by adding AlCl3 . A car. Iow ambient background. Samples were counted in a rier free solvent extraction with undiluted dilsobutyl. reproducible geometry, at both 6 and 11 cm from the carbinol was then carried out, using a succession of face of the detector cryostat. Counting rates were extraction /back extraction step"s to concentrate the sol.

sufficiently low so that corrections for pulse pileup, ume of solution containing Pa. Protactinium was random summing, and dead time were negligible, obtained finally in ~3 ml of 2 Af flCl/ trace liF Effects of coincidence summing were compensated for solution, sealed in a small polyethylene counting in all cases by using the ration of photopeaks of slal. Excellent decontamination from natural thorium the same isotope, each counted with the same effi.

ciency. Spectra were accumulated with a multichannel radioactivity"was achieved. analyzer resolution of 0.5 kev / channel. Photopeak fit.

Loss of 2 Pa during the chemistry was measured by isotopic tracing with 2"Pa, which decays with a ting and area determination by numericat integradon 1.3-day half life. Details of the tracer isotope produc. were done with the SKEWGAUS computer code.82 tion by means of the anThg2.n)2nPa reaction are presented elsewhere.8 ' The Pa in 2 Af IIC1/ trace liF was added to the irradiated thorium as it was being dissolved in acid. An equal amount of2 "Pa .

tracer solution was delivered directly to a counting vial ,. ,

i Target i Reactor and set aside as a control sample. Volumetric samp!ing

' I"8diated by micropipette was verified by weighing. After per. l "Ch'*I'*I * .*

forming the chemical separe.tlon, the spiked target 6. PP.*S " $

solution and the control sample were cach counted m under identical conditions by a Ge(LI) spectrometer. protactinium /

Using the photopeaks for two 2nPa decay Famma i 8"Pa counting for o thorium rs>s, at $94 and 969 kev, the ratio of the corrected L geld measurement j chemie.t counting rate for the target sample to the corrected P*' 8 t *a counting rate for the control gave a direct measure of the fractional recovery of protactinium. A 90% yield n, was obtained for both target separations. jou solution so.u dos.

Absolute Gamma Ray Cosmting The prominent 312 kev gamma ray from 2HPa Target decay was also counted using a Ge(LI) detector, after Rh allowing time for the relathely short lived 2"Pa tracer '*

• P

• Pa activity isotope activity to decay. As depleted schematically in Fig. 3 the measured counting rate for the separated engp target sample was compared indirectly with that for a #- depos:t 2"NpO 2deposit used as a stead 2[Sstate reference of 2nPa actisity. The intermediate Pa samples shown 1.3

, g a

y (standsd) in Fig. 3 were prepared from equal weight micro-pipette aliquots of a stock solution of 'Pa (i.e.. Dauted Esaporated protactinlum chemically separated from reactor. in vial on ptanchet activated thorium).

The 2"Np alpha particle activity of the2 "NpO2 o o o o deposit was calibrated by the NBS, using good geom- g g,,;, gg etry surface barrier detector counting, to be 6039 gama ray count Cynma ray count

(*0.25%) Bq (Ref.10). This calibration is assumed snea enp, to be equal to the disintegration rate of the 2"Np daughter, 2"Pa. The NHS alpha particle counting measurement w;u checked by a direct determination of l'ig. 3. Indirect measurement of '"Pa activity.

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NEUTRON ACTIV/, TION OF TIIORIUNI 127 i

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i ,. b 0.8 , , ,  !

u Room ikttdn Correction ,

3

! The 2nPa activity may result from the capture of epicadm!um room scattered neutrons (thermal neu-d I

trons are removed by cadmium shielding of the f source / target assembly). Grady" has measured the ~

j{

4 room return fraction of total actisity induced in indium foils. The thorium room return fraction was calculated as the product of the indium room return f- 0.6 - .}

%I fra: tion and the ratio of the resonance integrals. The  ! -} ..,

, , ' * ",q correction was negligible. R . 1 E ...pl ~...U

, , . . . , ,l" #' t!

j j f

Results j j'

The average of two measurements of the thorium g 1 l..g,N urg.

g capture cross section for antimony beryllium photo-neutrons was 606

• 19 mb. Errors are one standard deviation and are combined in quadrature. Prelimi-0 0.4 -

8 h(( ie cry values of these results can be found in Ref.14. ,_, Q 'ky {

- Macklin and llalperin (IIel.16)  ; .g q

DISCUSSION ff 1 .

To compare this result with other measurements 0.2 . , , ,

i' near 23 lev, we need to take into account the effect 18 20 22 24 26 28 .'

cf scattered neutrons comprising the "tail" of the Neutron energy (kev) i!

photoneutron energy spectrum, as wcll as those source tl photoneutrons in a second low intensity group near rig. 4. Neutron capture crou section of D2Th. p.

375 lev. We attribute 3.0% of the neutrons to the l' ,

f.

375 lev group," and c.1 eulate 1 the energy distribution of primarg group photoneutrons by blonte Carlo simulation shown in Fig. 2. For the relative shape of was a transmission experiment sning an antimony- a the cross section as a function of energy, we used both beryllium photoneutron source. Additional measure-I ENDF/Il V and the measurements of blacklin and ments would therefore seem to be appropriate in order llalperin." In either case, the resulting spectrum cor- to confirm an absolute normalization of the evaluated rection was negligible; we conclude that the cross see- thorium capture cross section in this energy range. h tion is 606 mb near 23 kcV (e.g., as measured with an )

approximately Gaussian shaped distribution with 2 y i

lev full width at half. maximum). This result further ACKNOWLEDGME NTS appe rs to be relatively insensitive to uncertainties in the cuct energy distribution and in the centroid energy Consultation with II. C. Griffm on sarious aspects ,

cf the neutron source. of the thorium-protactinium separation chemistry is ap.

Our measurement of the thor.ium capture cross preeisted.

section is plotted in Fig. 4, with error ban, and is com- This work has been supported by the U.S. Department h pared with the resuhs of hlacklin and llalperin" and of Enerry, d cf ENDF/il-V. 't he variation of the capture cross j section with energy .s this resonance region is 't.

cppreciable, as seen in Fig. 4 nrising from Duetuations i in the nuclear lesel spacing. Iloweser, these Ductua. REl i RENCES h tions are not resolved by the 2 kev broad primary antimony beryllium neutron group. I. J. MEADOWS, W. POLNITZ, A. SMITil, D. ,

We also note that our measurement is appreciably SMITil, J. Wil At EN, and R. IlOWERTON, *Esaluated 4 i'

higher than the iron filtered neutron beam measure- Nuelear Data lite of Th 2D," ant 3NDM 35, Argonne m nts rcported by Chrien et al." and by Yamamuro National Laboratory (1975). i (t al.". The Chrien et al. measurement was 540

• 14  ;  ;'

mh, while that of Yamamuro et al. was 520 a 45 mb. 2. G. VAsit 111 et al., 'Nuefear Data Esaluation for l iloweser, our value is in close agreement with a mea- Th 232," INDC (RUM) 10, International Nuclear Data 4 i surement by Ilclanova et al." (615125 mb), which Committee, International Atomic Energy Agency (1950). ,,

u couTaou;o. 7 7 9 4 0 {

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. .s

• O O 173 BALDWIN and KNOLL

3. W. P. POENITZ,'Tast Neutron Capture in U 238 and ' 11 R. J. GEllRKE, R. G. IIELMER, and C, W. I EICil, Th.252,* Standard Reference und Other important Nuclear Nuct. Sci. Eng., 70, 298 (1979).

Ibte, DNL NCS Sil23, ENDF400,11rookhaven National Laboratory (1930). 12. W. C. SClllCK, Jr., SKEWGAUS: A Tortran Pro-gram for Fitting Peaks in Semiconductor Detestor Sps:tra,"

4. G. F. KNOLL,"Absolute Fission Cross Section hica- IS 3460, Iowa State Unisersity (Oct.1974),

surements Using Fhed Energy Neutron Sources," Proc. Int.

Speclatuts' Symp. Neutron Standards and Applications, 13. D. J. GRADY, University of hiichigan, Priva,te com.

Gaithersburg. blar> land, h1 arch 28 31,1977. NDS Special munication (1980).

Publication 49), U.S. National Bureau of Standards (1977).

14. GEORGE T. BALDWIN and GLENN F. KNOI.L.

5. h!. C. DAYlS, PhD Dissertation, Univenity of hiich- Trans. A m. Nucl. Soc., 41, 571 (1932).

igan (1976).

6. C. ht. LEDERER and V. S. $111RLEY, Eds., Table of

/sotopes,7th ed., John Wiley and Sons, New York (1978). 16. R. L. htACKLIN and J. IIALPERIN, Nucl. Scl. f.ag.,

64, 849 (1977); see also R. L. blACKI IN and R. R.

7. W. !!. LAING, Oak didse National Laboistory, Pd- WINTERS, Nucl. Sci, l'ng., 73, 110 (197!),

sate Communication (1950).

17. R. E. CllRITN,11.1. LIOU, bl. J. KENNY, snd

8. G. T. BALDWIN, PhD Dissertation, University of h!, L. STEl.TS Nucl. Scl. Eng., 12, 202 (1979).

Stichigan (1931).

18. N. YAht Ah1URO, T. DOI, T. h11YAGAWA, Y.

9. G. T. BALDWIN,11. C. GRIFFIN, and G. F. FUJITA, K. KOHAYASill, and R. C. IILOCK, J. Nucl.

KNOLL. Radiochemical and Radioanaly tical Letters, 85, 3 Sci. Technol., 15, 631 (197 b). ,

235 (1954).

19. T. S. DELANOVA, A. A. VAN'KOV, F. F. htlK.

10. D. h!, G!LLI Ah!, U.S. National Bureau of Standards, ilAILUS, and Y. Y. STAYlSSKit, J. Nuct. Energy,20, Prisate Communication (1981). 411 (1966).

l l

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The University of Michigan Radiation Control Service 1101 North University Building Ann Arbor, MI 48109-1057 February 19, 1985 i

U.S. Nuclear Regulatory Commission Region III Haterials Licensing Section 799 Roosevelt Road Glen Ellyn IL 60137 Attention William Adams, Ph.D.

Re Amendment License No. SNH-179 Control No. 20788

Dear Dr. Adams:

In response to your recent request, we offer the following supplemental information in connection with our amendment application to add Np-237 to the SNM-179 licenset

1. Since the major contamination is alpha. activity, the investigator utll I take smear samples of vark surfaces following each experiment. The smear samples will be counted using a gas proportional counter available in the Phoenix Laboratory.

2. The experiment will be performed in a standard laboratory hood in l which the air is exhausted through the Phoenix Memoriat Laboratory exhaust i system. All such exhaust air is passed through an HEPA filter before its release to the environment. The exhaust system is equipped with a constant air monitoring system as described in FNR license R-28,

3. Personnel involved in the experiment will be required to wear gloves and a laboratory cost. After each experiment, a portable alpha survey meter will be used to check for any surface contamination. This alpha survey meter is available in the Phoenix Hemorial Laboratory.

1 I hope this information satisfies your request for docuenentation to complete 1 the application amending SNM-179. Please let me know if I can be of further I ass' stance.

O,g()

Sincerely yours, g6 CE eg O/ d q'  %

A. J. Solari. Director 950 AJS/dl 4503260049 050307 FEB 2 21335 Jp REC 3 LIC30 SNM-0179 PDR j j