ML20210F498
| ML20210F498 | |
| Person / Time | |
|---|---|
| Site: | 07000398 |
| Issue date: | 07/22/1999 |
| From: | Ting P NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | |
| Shared Package | |
| ML20210F494 | List: |
| References | |
| 70-0398-99-201, NUDOCS 9907300206 | |
| Download: ML20210F498 (6) | |
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U. S. NUCLEAR REGULATORY COMMISSION OFFICE OF NUCLEAR MATERIAL SAFETY AND SAFEGUARDS Docket No.:
70 398 License No.:
SNM-362 Report No.:
70-398/99-201 1
Licensee / Facility:
National Institute of Standards and Technology Location:
Gaithersburg, MD Jnspection Date:
July 13,1999 Inspectors:
Dennis Morey, Senior Criticality Safety inspector Sheryl Burrows, Criticality Safety inspector Approved by:
Philip Ting, Chief Operations Branch Division of Fuel Cycle Safety and Safeguards, NMSS Enclosure 9907300206 990722
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PDR ADOCK 07000398 C
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NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY NRC INSPECTION REPORT 70-398/99-201 l
EXECUTIVE
SUMMARY
l This inspection was conducted per 10 CFR Part 70 under Temporary Instruction 2600/004 to ensure that programs are in place and adequately implemented to safely handle and store the special nuclear material (SNM) located at the National Institute of Standards and Technology (NIST) facility. Areas inspected included: Building 245, Material Storage Area; Building 345, Material Storage and Receiving Area, and Building 227, Advanced Chemical Sciences and Technology.
Fissile Material Operations The inspectors concluded that the licensee SNM operations are planned and conducted i
in accordance with applicable procedures and deal with such small quantities of SNM that they are of minor safety significance with respect to criticality safety. NIST does not currently possess and use SNM in quantities and forms sufficient to form a critical mass.
Fissile Material Storaae The inspectors concluded that, under all credible storage conditions, the licensee SNM could not sustain a chain reaction by itself. The inspectors concluded that the licensee limits on material mass would assure the criticality safety of the material. Licensee operational procedures implement the mass limits in the license and are considered adequate to assure criticality safety of the SNM in storage.
Criticality Safety Analysis NIST uses procedures and controls to insure that there is not enough SNM used or stored at any single location to constitute a critical mass. The unity rule (Chapter 6, Part I of the materials license) which limits the amount of SNM stored and used at NIST i
is adequate to assure criticality safety. NIST has procedures to implement this license condition. Therefore, a formal criticality safety analysis is not required. This is acceptable for the level of risk that was apparent at the facility.
3 REPORT DETAILS 1.
Fissile Material Operations a.
Inspection Scope The inspectors performed a walkthrough of SNM storage and handling areas at the NIST facility to determine the location of SNM, the extent and nature of fissile material operations, and to identify any significant criticality safety issues.
b.
Observations and Findinas The licensed special nuclear material (SNM) at NIST is contained in three areas.
Building 245 contains gram amounts of uranium and plutonium metals used for calibrations. Building 235 contains gram quantities of uranium and plutonium as well as a 10-gram and a 1-gram Plutonium-Beryllium neutron source. Building 227 contains gram quantities of uranium and plutonium metals and dilute solutions (microgram to gram quantities of SNM) of uranium and plutonium used for calibrations. The uranium consists of high enriched uranium, low enriched uranium, and very small quantities (less than 0.5 gram) of uranium-233. The plutonium consists of plutonium 239 and 241, and very small quantities (less than 0.5 gram) of plutonium 238 and 242. Individual sources are of gram quantities or less, and no operation or storage area was observed with more than gram quantities of any individual source.
c.
Conclusions The inspectors concluded that the licensee SNM operations are planned and conducted in accordance with applicable procedures and deal with such small quantities of SNM that they are of minor safety significance with respect to criticality safety. NIST does not currently possess and use SNM in quantities and forms sufficient to form a critical mass.
Licensee documentation indicated that all of the SNM on site is not enough to form critical mass. The inspectors also observed that all the SNM allowed by the license, all in the same location at the same time, was not in a form that would readily sustain a chain reaction.
2.
Fissile Material Storage a.
Inspection Scope in order to verify criticality safety of storage conditions, the inspectors performed a walkthrough and physical inspection of all three locations at NIST where SNM is stored.
This included a storage area in the basement of Building 245, a shipping / receiving and storage area in Building 235, and a storage area in Building 227, Advanced Chemical Science and Technology Facility.
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i b.
Observations and Findinas The inspectors observed that the licensee SNM storage locations were properly labeled i
and locked with access granted only to the three primary SNM custodians and a backup j
in each case. All individual sources were gram quantities or less and all were labeled.
The sum of the material in all three locations is not enough to form a critical mass. The i
inspectors observed the licensee logbook for the semi-annual inventory of the sources and reviewed licensee procedures to determine if the material was controlled in accordance with license requirements. The inspectors determined that reactor fuel, maintained by the licensee at the facility, is stored separately and handled in accordance with procedures such that it is not expected to come into contact with the other SNM.
c.
Conclusions The inspectors concluded that, under all credible storage conditions, the licensee SNM could not sustain a chain reaction by itself. The inspectors concluded that the licensee i
limits on material mass would assure the criticality safety of the material. Licensee operational procedures implement the mass limits in the license and are considered adequate to assure criticality safety of the SNM in storage.
3.
Criticality Safety Analysis a.
Inspection Scope The inspectors reviewed licensee criticality safety documentation to determine whether analysis of fissile material operations was performed in accordance with license commitments and is commensurate with risk of criticality at the facility, j
b.
Observations and Findinas License SNM-362, Chapter 6 requires that NIST does not posses and use special nuclear material in quantities and forms sufficient to form a critical mass. That is NIST possesses and uses less than 350 grams of uranium-235,200 grams of uranium-233, 200 grams of plutonium (in any form other than plutonium-beryllium neutron sources), or any combination of them in accordance with the unity rule shown below:
grams U-235/350 + grams U-233/200 + grams Pu/200 5 1 The inspectors reviewed the implementing procedures for this license requirement (HPl 1.5, *SNM Accountability", and HPl 4.4, " Accountability and Control") and found them to be adequate. As long as this criteria is met, the licensee is not required to perform any other criticality analysis.
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5 The inspectors noted that the licensee handles reactor fuel at the Building 235 facility in support of reactor operations. The licensee has a separate license under 10 CFR Part 50 to operate the reactor and conduct related activities such as fuel handling. The inspectors reviewed the interface between the reactor and SNM operations. The inspectors walked down the flow path and storage location of the reactor fuel and determined that procedural restrictions on the use and storage of the fuel are sufficient to preclude intermingling with SNM. The inspectors did not identify any safety issues with the interface between material handled under the Part 50 and Part 70 licenses.
c.
Conclusions NIST uses procedures and controls to insure that there is not enough SNM used or stored at any single location to constitute a critical mass. The unity rule (Chapter 6, Part I of the materials license) which limits the amount of SNM stored and used at NIST is adequate to assure criticality safety. The ilspectors determined that NIST has procedures to implement this license condition. Therefore, a formal criticality safety analysis is not required. The unity rule was found to be acceptable for the level of risk l
that was apparent at the facility.
4.
Exit Meeting The inspectors met with NIST representatives throughout the inspection. The inspectors presented the inspection results to members of the licensee management and staff during the exit meeting on July 13,1999. No classified or proprietary information was discussed. At the exit meeting, NIST representatives acknowledged the results presented.
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6 PARTIAL LIST OF PERSONS CONTACTED NIST
- Thomas Hobbs, Chief, Health Physics and SNM Accountability Officer
- Barbara Biss, SNM Accountability Assistant Pam Hodge, SNM Custodian Dick Lindstrom, SNM Custodian Ellen Beary, SNM Custodian NRC Dennis Morey, NRC Senior Criticality Safety inspector Sheryl Burrows, NRC Criticality Safety inspector
- Attended exit meeting ACRONYMS USED NIST National Institute of Standards and Technology NRC Nuclear Regulatory Commission SNM Special Nuclear Material U
Uranium HEU High Enriched Uranium LEU Low Enriched Uranium Pu Plutonium l
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