ML20246D149
| ML20246D149 | |
| Person / Time | |
|---|---|
| Site: | 07000920 |
| Issue date: | 04/20/1989 |
| From: | Ryan R RENSSELAER POLYTECHNIC INSTITUTE, TROY, NY |
| To: | Pennington W NRC |
| References | |
| 25456, NUDOCS 8905100136 | |
| Download: ML20246D149 (5) | |
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USNRC April 20, 1989 i
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APR231989 )j t
NM'>S Mall, OECTION Mr. W.
Scott Pennington g
DOCKET CLERK U.S. Nuclear Regulatory Commission tu j;, \\'g
' Uranium Fuel Licensing Branch Division of Fuel Cycle.and Nuclear Safety
' Washington, DC 20555
Reference:
NRC License SNM-910
Subject:
Additional Information to Rensselaer's Request for Amendment dated February 22, 1989.
Gentlemen:
The following information is being supplied in support of the above subject amendment request as per our phone conversation of April 18, 1989.
1.
The purpose of the slowing down time (SDT) assay method is to perform non-destructive fissile assay in nuclear fuel.
The SDT technique requires accelerator production of pulsed neutrons together with a pile of lead.
In the present application 64 SPET (F-1) Fuel Pins are placed in the FAFFA (Euel Assembly Eor Eissile Assay), and the assembly is put inside the pile of lead.
The SDT technique works as follows.
Fast neutrons are produced in a helium cooled tantalum photoneutron target, which is positioned in the center of a cubic pile of lead (180 cm side). Lead serves to slow down neutrons as well as a radiation shielding.
elastic scattering in lead, uranium and other heavy element of mass A in the fuel, focuses the neutrons to a relative pulse width AE/E approximately equal to 5/A1/2 As time goes on the focused (in energy) pulse passes across the distinctive fission cross sections of the various fissile isotopes. Measurement of prompt fission neutrons (from fuel in the FAFFA) as a function of time then provides the assay information to distinguish fissile isotopes.
The fission chambers placed around the FAFFA measure the prompt fission neutrons from the fuel.
Finally, the fission chamber, placed inside the FAFFA when located in the lead assembly, will fos 1 i gr/M M Remseber Polytechnic Institute + Tmy. New Brk 12180-3590 + (51H 24401U4013 8905100136 890420 PDR ADOCK 07000920 25 f456 C
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Mr. W.
Scott Pennington Page 2 l
l measure the interrogating neutron flux in the interior of the FAFFA.
The neutron spectrum in the lead pile is approximated by the equation,
$(E)dE =
dE EO 775 Where E is the energy of the neutron in units of electron volts
$(E) is the neutron fluence rate in units of neutron per 2
cm per sec per eV.
P is the electron beam power on target in units of watts 2.
The fraction of personnel exposed to ionizing radiation during the experiment (about 4) and the projected dose equivalence each could receive is a very small fraction of that recommended as limits in 10CRF20 " Radiation Protection". (about 10 mrem). We do not expect the FAFFA to emit radiation exceeding SmRem/hr. as measured at 1 meter based on historical data of other experiments.
3.
The attached figures 1 and le show the Gaerttner Laboratory plan view and the location of the Pb spectrometer in the target room.
When in use the FAFFA will be in the Pb spectrometer. When not in the Pb spectrometer it will be secured in a storage rack located along the wall of the west entrance into the target room within the concrete doors.
4.
The security including the access control will remain as per our currently licensed commitment to the NRC.
The location of the FAFFA "xperiment is in an area currently authorized for use under the existing SNM-910 license.
I hope the above information meets with your needs, and that it will result in the issuance of the requested amendment to Rensselaer SNM-910.
Sincerely, D CC Robert M. Ryan, 1 rector Office of Radiation and Nuclear Safety RMR/bal
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