ML20247Q448
| ML20247Q448 | |
| Person / Time | |
|---|---|
| Site: | 07000920 |
| Issue date: | 05/31/1989 |
| From: | Bidinger G, Pennington W NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | |
| Shared Package | |
| ML20247Q420 | List: |
| References | |
| NUDOCS 8906060434 | |
| Download: ML20247Q448 (3) | |
Text
- -.
MAY 311989 DOCKET N0:
70-920 LICENSEE:
Rensselaer Polytechnic Institute (RPI)
Troy, New York
SUBJECT:
SAFETY EVALUATION REPORT, LICENSE AMENDMENT APPLICATION DATED FEBRUARY 22, 1989, AND SUPPLEMENTS DATED MARCH 9, AND APRIL 12
~AND 20, 1989, RE NON-DESTRUCTIVE ASSAY OF FISSIONABLE MATERIAL IN SPERT FUEL-
Background
In-the subject application, as supplemented, RPI has requested Materials.
License No. SNM-910 be amended to authorize the possession and use of special nuclear material (SNM) contained in 64 SPERT F-1 fuel rods for the purpose of conducting a non-destructive assay of the fissionable material in SPERT fuel. The fuel rods are currently stored at RPI's Critical Reactor Facility which is licensed in accordance with 10 CFR Part 50.
Discussion Possession Limit RPI has requested that the current possession limits be increased to include 2252.8 grams of U-235. The requested material is in the form of uranium dioxide fuel pellets enriched to 4.81 + 0.15 percent by weight in the U-235 isotope. To clarify the licensee's description of the requested material, form, and quantity, the staff recommends that Conditions 6, 7, and 8 be revised to include the following:
k hhterial Form Quantity I.
Uranium enriched up to I.
Uranium dioxide in I.
2,300 grams 4.96 w/o U-235 SPERT fuel rods U-235 Proposed Activity In the existing license, RPI is authorized to use licensed material for educational research and development activities at the Lineat Accelerator Laboratory (LINAC). The licensee has proposed to use the requested material j
for assaying its fissionable content by neutron interrogation. The material will be transferred from the Critical Reactor Facility to the LINAC and installed in the Fuel Assembly for Fissile Assay (FAFFA). The fuel rods will l
be stored at the LINAC target room either in the shipping container or in the FAFFA. Upon completion of the assay, the fuel rods will be returned to the 4
Critical Reactor Facility in the shipping container.
l l
l l
i 8906060434 890531 ADOCK07000920f; I
PDR C
PNu i
I
MAY 31 M l
Rensselaer Polytechnic Institute 2
The FAFFA will be loaded with the SPERT fuel rods and placed in the Rensselaer i
Intense Neutron Spectrometer (RINS) for the fuel assay.
In the RINS, the l
SPERT fuel will be interrogated with pulsed neutrons. The neutrons will be
{
indirectly produced by high energy electron bombardment of a tantalum target
?
in the RINS. The high energy electrons will be' generated with RPI's linear accelerator.
I Miniature fission chambers will be placed inside and around the FAFFA to
{
measure the prompt fission neutrons from the fuel and the interrogating neutron flux, respectively. Several of the fission chambers will.contain SNM of less than 1 gram quantities. The measurement of the prompt fission' neutrons as a 1
function of time will provide the assay information needed to distinguish the fissile isotopes.
RPI has not requested authorization for the use of the linear accelerator or the possession of byproduct material resulting from its operation. The State of New York regulates the use of linear accelerators and the possession of byproduct material.
Radiation Safety Prior to the loading of the fuel rods in the FAFFA and periodically thereaf ter, the rods will be smeared for contamination. However, because the fuel is contained in sealed stainless steel tubing, airborne and removable contamination should be of no concern. The existing license requires that prior to activation of the linear accelerator, the accelerator facility will be visually inspected to insure that all personnel have cleared the area. The entrance to the facility is equipped with an interlock which deactivates the accelerator if the door is opened.
Following the operation of the accelerator, a radiation survey is made when entering the facility if the accelerator's operation induced radioactivity.
The licensee reports that the assay should not result in a need for additional radiation shielding when handling the fuel rods or FAFFA.
Based on previous experiments, RPI expects that the radiation field as measured at 1 meter from the FAFFA following neutron interrogation will not exceed 5 mrem /hr. RPI estimates that the personnel exposures resulting from the proposed activity should be about 10 mrem per person, well below the limits in 10 CFR Part 20.
l Nuclear Criticality Safety Each SPERT fuel rod consists of 4.81 + 0.15 percent by weight U-235 uranium dioxide pellets contained in stainless steel tubing. The fuel pellets are right circular cylinders with a nominal diameter of 0.466 inches. The active fuel length of the rod is 36 inches.
l RPI proposes to load 64 rods (2252.8 g U-235) into the aluminum structure of the FAFFA. The FAFFA rods will placed in an 8 x 8 array which maintains a fuel rod pitch of 0.64 inches. The licensee reported the k for this storage array to be about 0.70.
Thecalculationswereperform@usingtheLEOPARD-DIFXYRZ code. Staff confirmed the licensee's results by calculating the array using the 27-group cross-section set which is found in the SCALE program, along with KENO-Va, a Monte Carlo code. The results are independent of the degree of water moderation within the array or the degree of water reflection surrounding the i
array.
I
.___________.-___._____.-_a
t.
MAY - 311989
. Rensselaer Polytechnic Institute 3'
~
The licensee has stated that a criticality monitor will be provided and operating when the linear accelerator is not being used. Due to the radiation intensity associated with the operation of the. linear accelerator, a criticality. monitor would'not be effective during its operation. -Therefore, an exemption to the monitoring requirements of 10 CFR 70.24 is necessary when the linear accelerator is' operating. The safety interlock previously described provides assurance that no personnel are within the facility while
-the accelerator is operating. With no personnel in the facility, no-fuel movement will occur and therefore, a criticality monitor is not necessary.
However, once the accelerator is deactivated, the criticality monitor will be turned on. The license' currently exempts the licensee'from the monitoring.
requirements of 10 CFR Part 70 provided that no more than 450 grams of special nuclear material, excluding encapsulated Pu-Be neutron sources, is present in any one-room at any one time. To maintain the exemption for the currently licensed material and +c exempt the licensee from the monitoring requirements of 10 CFR 70.24 for.'n. SPERT fuel while the linear accelerator is operating, the staff-recommends. at Condition 28 be revised and Condition 30 be added as follows:
- 28. The licensee is hereby exempt from the provisions of 10 CFR 70.24 insofar as this section applies to the materials specified in Condition 6.A-H and provided that no more than 450 grams of special nuclear material, excluding encapsulated Pu.Be neutron sources, is present in any one room'at any one. time.
- 30. The licensee is hereby exempt from the provisions of 10 CFR 70.24 insofar as this section applies to the materials specified in Condition 6.I. when the linear accelerator is operating.
Conclusions / Recommendations Based on the discussion, the staff concludes that the authorized possession and use of the SPERT fuel rods for assay of fissile material will neither significantly increase radiation exposure to RPI personnel or adversely affect the protection provided for the health and safety of the public or the environment.
Therefore, staff recommends approval of the application, as supplemented, and in accordance with 10 CFR 51.22(c)(14)(v), neither an Environmental Assessment -
nor an Environmental Impact Statement is warranted.
the amendment application was discussed with the Region I Principal Inspector.
He has no objection to amending the license.
OrignalSigned Br 6, //f W. Scott Pennington Uranium Fuel Section Fuel Cycle Safety Branch Division of Industrial and Medical Nuclear Safety, NMSS l
Approved by:
OJWOSI bIEUDd 8I I
George H. Bidinger, Section Leader OFC:IMUF:
IMUF:
IMUF*
IMUF:o - -
0 'y_Q._.IMUF :m
_...g2& ton:mh:
t
....fL
~
NAME:WSPenwing VLt e: /
MHorn:
DAMcCaugh y; GHBidinger:
DATE:5/%'/89 5/9/89 5/24/89 5/f(,/89 5/A,/89 0FFICIAL RECORD COPY