ML20246P129

SER Supporting 890210 Application for Amend to License SNM-33,modifying One of Three Conversion Reactors.Approval of Amend Application Recommended

ML20246P129
Person / Time
Site:	07000036
Issue date:	05/10/1989
From:	Bidinger G, Mccaughey D NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS)
To:
Shared Package
ML20246P114	List: ML20246P111 ML20246P122 ML20246P129 ML20246P142
References
NUDOCS 8905220092
Download: ML20246P129 (2)

Text

.

4 MAY 101989 DOCKET N0: 70-36 LICENSEE: Combustion Engineering, Inc. (CE)

Hematite, Missouri

SUBJECT:

SAFETY EVALUATION REPORT, APPLICATION DATED FEBRUARY 10, 1989, RE MODIFICATION OF R-2 CONVERSION REACTOR

Background

CE is authorized to convert UF g to U0 using a dry fluidized bed conversion procen. In the subject application,2CE proposes modification to one of the three conversion reactors (R-2).

Discussion The R-2 reactor is used to reduce U0 F,3 to U0, utilizing either " cracked" ammonsa or hydrogen. Thecurrentde$ignoftheR-2reactorconsistsofa10-inch diameter lower cylinder connected to an upper 12-inch diameter disengaging column. The proposed modification involves the addition of a 16-inch diameter dicuigaging section to the upper end of the reactor. This modification.. will reduce material carryover, minimize recycle, and reduce material handling.

A previous analysis performed by the licensee of a worse-case situation yielded a k-effective of 0.95 for a single reactor and 0.97 for the conversion process a rray. NRC staff accepted these values based on a number of process controls and fail-safe alarm features associated with the conversion system.

With respect to the subject application, the licensee failed to provide an analysis demonstrating the nuclear criticality safety of the modified system.

Staff analyzed the R-2 reactor assuming the reactor is entirely filled with 5 percent enriched 007 powder at a density of 2.5g UO /cc 2 and homogeneously mixed with water. At opt'imum moderation, the k-effective values produced exceeded u ni ty . Therefore, if the situation described above occurs, the possibility exists for a criticality accident. However, in Part II of the application, the licensee presented a number of process and administrative controls to provide assurance that the above situation is never realized.

The steam supply line to the R-2 reactor has two spring-loaded shutoff valves to terminate steam flow under abnormal situations. High and low temperature indicators on the R-2 reactor are interlocked to both valves. A second, redundant, low temperature indicator on the R-2 reactor is interlocked to both valves, therefore, providing continual control even in the event of primary indicator failure. Differential pressure instrumentation is also provided on the R-2 reactor and interlocked to the shutoff valves. Therefore, loss of power to the plant, high or low reactor temperatures, and high system pressure would cause the steam control valves to close. In addition to these 8905220092 890510 6 PDR ADOCK 0700 C

L 1 4

MAY 101989

. . Combustion Engineering, Inc. 2 interlocks, high' pressure and. low temperature alarms are provided, thus alerting the operator.to take necessary action. If all of these controls failed, more than 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> of steam flow would be required to fill the 10. inch ~

reactor with condensed steam. The reactor is unloaded at 2-hour intervals so I that the water would be discharged through the powder valve system. The

' licensee.has committed to calibrate the high pressure switches'and test the-operability 'of. the control system every 6 months.

.The staff believes that_'hese t controls are sufficient to prevent the accumulation of special nuclear material and water in the 16 inch diameter upper disengaging section.

Conclusion / Recommendation The staff concludes that! the proposed modification will have no adverse effect on the.public health and safety or the environment. Approval of the amendment application is recommended.

The Region III Principal, Inspector has no objection to this proposed action.

kWE81 Signed By-David A. McCaughey Uranium Fuel Section Fuel Cycle Safety Branch Division of Industrial and Medical Nuclear Safety, NHSS WsmalSigned Rr Approved by: _

George H. B1dinger, Section Leader l

L i

l OFC:IMUF: IMUF: IMUF: g NkhEDkM ey mh$ bbBidinge$

VLThe$

DATE:5/D/89 5/fD/89 5/#O/89 0FFICIAl RECORD COPY