ML20154A555
| ML20154A555 | |
| Person / Time | |
|---|---|
| Site: | Paducah Gaseous Diffusion Plant |
| Issue date: | 09/25/1998 |
| From: | Toelle S UNITED STATES ENRICHMENT CORP. (USEC) |
| To: | Paperiello C NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| References | |
| GDP-98-0205, GDP-98-205, NUDOCS 9810020342 | |
| Download: ML20154A555 (3) | |
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USEC A Global Energy Company l
September 25,1998 GDP 98-0205 Dr. Carl J. Paperiello Director, Offke of Nuclear Material Safety and Safeguards Attention: Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001 Paducah Gaseous Diffusion Plant (PGDP)
Docket No. 70-7001 Criticality Accident Alarm System Detection Exclusion Request for Cylinder Storage Yard l
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Dear Dr. Paperiello:
Pursuant to 10 CFR 76.89(a), USEC is requesting approval of an exclusion from the Criticality Accident Alarm System (CAAS) detection coverage requirements for the C-745-U cylinder storage yard. The C-745-U cylinder storage yard is being constructed in the southeast region of the Controlled Access Area (CAA) and is scheduled to be completed in late 1998. Upon completion of the yard, C-745-U will be utilized by USEC to store UF cylinders that contain toll normal material, 6
2 tails materials, and heels from toll normal material (<1 wt% "U).
10 CFR Part 76.89 requires a criticality monitoring and alarm system for all areas of the facility except for approved exclusions. In accordance with 10 CFR Part 76.89, and as stated in Issue 8 of the Plan for Achieving Compliance with NRC Regulations at the PGDP, USEC submitted letter GDP 96-0172, dated August 15, 1996, to the NRC requesting exclusion from CAAS detection coverage for specified areas. This was supplemented by a response to a Request for Additional Information in letter GDP-97-0051. These letters, GDP 96-0172 and GDP 97-0051, included justification for excluding UF cylinder storage yards from CAAS coverage.
6 As stated in the letters, GDP 96-0172 and GDP 97-0051, in order for a nuclear criticality to occar, a breach of a UF cylinder and subsequent introduction of a sufficient quantity of water to convert 6
a suitable quantity of UF to uranyl fluoride and to also provide sufficiert neutron moderation and 6
(f'\\y reflection is necessary before a nuclear criticality can occur. In addition, tne physical integrity of the cylinders which meet ANSI N.14.1, the special procedures and equipment for cylinder handling, F
9810020342 990925 PDR ADOCK 07007001 C
PDR g 6903 Rockledge Drive, Bethesda, MD 20817 1818 Telephone 301-564-3200 Fax 301-5(A-3201 http://www.usec com Offices in Livermore. CA Paducah. KY Portsmouth, OH Washington, DC k
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Dr. Carl J. Paperiello September 25,1998 GDP 98-0205, Page 2 movement, and storage, and the requirements for inspection of UF. cylinacrs in storage have been sufficient to ensure only a few isolated instances of either cylinder breach or holes induced by corrosion. These isolated cases are the only cases that have occurred in nearly one-hundred thousand cylinder yard transfers. Furthermore, tests have confirmed that the physical and chemical properties of solid UF in contact with water and a steel container act to severely retard the entry of water, and further retard the movement of water into the bulk cylinder. This behavior provides a period of years after breach occurs for subsequent detection. Thus, on the basis of the extren:ely low likelihood of cylinder breach and subsequent low likelihood of introduction of sufficient moderation into the cylinder to sufficiently convert, moderate, and provide neutron reflection, a nuclear criticality is not deemed to be credible.
Furthermore, evaluations have been performed which concluded that cylinders containing UF.
enriched to less than 1 wt% 2"U cannot credibly be made critical. Therefore, a nuclear criticality in the C-745-U cylinder yard is not credible. Attaciunent I provides additional information regarding the procedures pertaining to cylinder storage in the C-745-U yard.
In conclusion, NRC approval for CAAS exemption is requested for the C-745-U cylinder storage yard prior to conunencing cylinder storage operations, which is currently scheduled for October 15, 1998. Should you have any questions or require additional information, please contact Marc Klasky at (301) 564-3408. There are no new commitments contained in this submittal.
Sincerely,
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- 5. A.
I Steven A.Toelle Nuclear Regulatory Assurance and Policy Manager
Enclosure:
As stated cc: NRC Region III Office NRC Resident Inspector, PGDP NRC Resident Inspector, PORTS i-L
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o GDP 98-0205 Page1of1 Additional Justification for CAAS Exclusion in C-745-U Cylinder Storage Yard As committed to in the Application for Certification, USEC maintains requirements for cylinder handling operations in cylinder storage yards at the Paducah Gaseous Diffusion Plant (PGDP) through the use of plant procedures, tmining, and surveillances. Personnel responsible for the handling of special nuclear u.aterial and cylinder operations are trained to ensure that cylinders or equipment that may exceed the <lut. % U limits are not brought into toll normal and tails cylinder 235 storage yards, such as the C-745-U cylinder yard.
Workers at PGDP are required to participate in General Employee Training (GET). GET training and/or testing is required every two years. This training includes general Nuclear Criticality Safety (NCS) training that addresses criticality safety concerns and the potential for criticality accidents.
The training emphasizes the NCS postings (which delineate the NCS controls), Fissile Control Area markings (which identify areas under NCS controls), and that only specially trained personnel are allowed to move or handle fissile material.
j Personnel who are allowed to handle or direct the activities of workers who handle fissile /potentially fissile material (e.g., managers, handlers, design engineers, operators, etc.) are also required to complete much more detailed criticality safety training. This training discusses the definition of fissile material, explains the parameters associated with criticality safety, and explains the l
upplication of these principles. In addition, this training covers personnel responsibilities related to criticality safety including obtaining the appropriate approvals prior to performing fissile material operations.
To ensure compliance with the NCS program requirements specified in plant procedures, walk-throughs and surveillances are performed by NCS, plant management, and the Safety, Safeguards and Quality Organization. These walk-throughs and surveillances are performed in part to ensure 235 that operations involving uranium enriched to lwt.%
U or higher have been reviewed and approved by NCS, as well as to verify that conditions have not been altered to adversely effect NCS.
This review and approval includes compliance with CAAS requirements.
Nuclear Criticality Safety program requirements are implemented through the plant NCS procedures, 235 training, and administrative controls. Operations involving uranium enriched to lwt.%
U or l
higher and > 15g of U are controlled through the NCS program to prevent unauthorized storage i
or movement of material in cylinder storage yards limited to toll normal and tails cylinder storage, j
thus eliminating the requirement for CAAS coverage in the C-745-U cylinder storage yard.
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