ML20155C009
| ML20155C009 | |
| Person / Time | |
|---|---|
| Site: | Portsmouth Gaseous Diffusion Plant, Paducah Gaseous Diffusion Plant |
| Issue date: | 10/23/1998 |
| 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-98-0225, GDP-98-225, NUDOCS 9811020039 | |
| Download: ML20155C009 (3) | |
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1 USEC A Global Energy Company October 23,1998 GDP 98-0225 q
Dr. Carl J. Paperiello Director, Office 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)
Portsmouth Gaseous Diffusion Plant (PORTS)
Docket Nos. 70-7001 & 70-7002 Safety Analysis Report Update - PIPELEAK Cylinder Modeling
Dear Dr. Paperiello:
s By letters dated October 31,1997 (References 1 and 2). USEC submitted certificate amendment requests containing the Safety Analysis Report Updates (SARUPs) required by Issue 2 of the Compliance Plans (References 3 and 4). USEC's Octol>:r 31,1997 letters contained the following commitment:
PIPELEAK Cylinder Modeling The PIPELEAK code is a variant of the CYLIND code developed by the NRC to estimate release rates for UF cylinders. During USEC's review of the DOE SAR 6
Upgrade (KY/EM-174), it was discovered that PIPELEAK models UF cylinders as 6
right circular cylinders.
The amount ofliquid UF released during an accident 6
scenario is determined by the height of the phase interface.
According to NUREG/CR-4360 (pg. 41), a right circular cylinder was chosen as the geometry to be modeled because it corresponds well to most process vessels as well as to cylinders used to store UF. However, because cylinders have elliptical heads, the amount of 6
liquid released during an accident may not be accurately modeled by the PIPELEAK code. This inaccuracy may affect the results of the S ARUP accident analysis and the 3
revised TSRs.
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To correct this deficiency, a new equation for calculating the phase interface will be developed and incorporated into the code. Once the PIPELEAK code has been revised, the affected source term and consequence analyses will be revised and the results incorporated into SARUP. The results of the revised source term and 9811020039 981023 PDR ADOCK 07007001 C
PDR Jrive, Bethesda, MD 20817-1818
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Telephone 301-564-3200 Fax 301-564-3201 http://www.usec.com Offices in Livermore, CA Paducah, KY Portsmouth, OH Washington, DC
1 Dr. Carl J. Paperiello i
October 73,1998 GDP 98-0225, Page 2 consequence analyses, including any necessary changes to the SARUP, will be t
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submitted to the NRC by December 31,1998.
1
]s The PIPELEAK code is a variant of the CYLIND code developed by the NRC to estimate release rates for UF, cylinders. PIPELEAK models UF cylinders as right circular cylinders. However, the 6
actual cylinders have elliptical heads. It was thought that this inaccuracy could affect the results of the SARUP accident analysis and the proposed SARUP TSRs.
A modified version of PIPELEAK was created to account for the presence of elliptical heads, and cource terms were re-calculated for a representative SARUP scenario. A comparison of release rates and total releases for the SARUP submittal and for the revised source terms showed that the results in the SARUP submittal are slightly higher. H' wever, the reduction in SARUP source terms that would be achieved by modeling the elliptical heads would not significantly affect the results of any scenario and would not change any of the proposed SARUP TSR controls. Consequently, USEC does not plan to revise the source term and consequence analyses, and no revision to the SABUP accident analyses will be submitted to the NRC. Furthermore, the current version of PIPELEAK referenced in SARUP will continue to be used for future SARUP-related analyses.
Should you have questions related to this subject, please contact Steve Routh at (301) 564-3251.
There are no new commitments contained in this submittal.
Sincerely, A
S. A.
In Steven A. Toelle Nuclear Regulatory Assurance and Policy Manager q
References:
1.
Letter from James H. Miller (USEC) to Dr. Carl J. Paperiello (NRC),
" Certificate Amendment Request - Update the Application Safety Analysis Report," Paducah Gaseous Di&sion Plant, Letter No. GDP 97-0188, October 31,1997.
i 2.
Letter from James H. Miller (USEC) to Dr. Carl J. Paperiello (NRC),
" Certificate Amendment Request - Update the Application Safety Analysis Report," Portsmouth Gaseous Di&sion Plant, Letter No. GDP 97-0189, q
October 31,1997.
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3.
DOE /ORO-2026," Plan for Achieving Compliance With NRC Regulations at j
the Paducah Gaseous Di%sion Plant."
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4.
DOE /ORO-2027," Plan for Achieving Compliance With NRC Regulations at
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j the Portsmouth Gaseous Di&sion Plant."
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L; Dr. Carl J. Paperiello Qctober,23,1998 GDP 98-0225, Page 3 cc:
Mr. Robert C. Pierson, NRC-HQ L;'
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NRC Region 11I Office L-NRC Resident Inspector - PGDP (f
NRC Resident Inspector - PORTS Mr. Randall M. DeVault u
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