ML20203J226
| ML20203J226 | |
| Person / Time | |
|---|---|
| Site: | Portsmouth Gaseous Diffusion Plant, Paducah Gaseous Diffusion Plant |
| Issue date: | 02/25/1998 |
| From: | Cox C NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | John Miller UNITED STATES ENRICHMENT CORP. (USEC) |
| References | |
| TAC-L32043, TAC-L32044, NUDOCS 9803040022 | |
| Download: ML20203J226 (4) | |
Text
February 25, 1998 Mr. James H. Miller Vice President, Production U. S. Enrichment Corporation 2 Democracy Center 6903 Rockledge Drive Bethesda, MD 20817
SUBJECT:
PADUCAH AND PORTSMOUTH CERTIFICATE AMENDMENT REQUESTS-UPDATE THE APPLICATION SAFETY ANALYSIS (TAC NOS. L32043 & L32044)
Dear Mr. Miller:
l This refers to your applications dated October 31,1997, requesting amendments to the Certificates of Compliance for the Paducah Gaseous Diffusion Plant and the Portsmouth l
Gaseous Diffusion Plant. The amendments were updating the application Safety Analysis Reports (SARs) based upon the Safety Analysis Report Upgrade (SARUP) program.
Our review of your application has identified additional information that is needed before final action can be taken on your request. The additionalinformation, specified in the enclosure, should be provided within 30 days of this letter. Please reference the above TAC Nos. in future correspondence related to this request.
If you have any questions, I can be reached at (301) 415-7655.
Sincerely, Odetnal bignett B" Charles Cox Mechanical Systems Engineer Special Projects Branch Division of Fuel Cycle Safety and Safeguards, NMSS Dockets 70-7001,70 7002 Certificates GDP-1,GDP-2
Enclosure:
As stated I
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l Mr. Steve Polston, PGDP Mr. James Morgan, PORTS i
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Request for Additional Information Applications Dated October 31,1997 gUnited States Enrichment Corporation
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Paducah Gaseous Diffusion Plant Docket 70-7001 Portsmouth Gaseous Diffusion Plant Docket 70-7002 Please provide the following information:
1.
The cover letters dated October 31,1997, states that information in the SARUP (both Paducah and Portsmouth) involves an unreviewed safety question. It was recognized in the Compliance Plans that the SARUP would involve raising unreviewed safety quesilons based on the fact new criteria and methodologies would be used in the accident analysis chapter. The Compliance Plans provided a protocol for reporting significant safety issues in the Justification for Continued Operations. The protocol required DOE to report to the NRC before transition if any significant safety issees were identified in the SARUP process and after transition for USEC to follow 10 CFR 76.9(b) reportin,; for any safety significant issue, Enclosure 2 Item 4, of the SARUP cover letters identify significant increases in the probability of occurrences or consequences of previously evaluated accidents. The conclusions in those sections would appear to state that those events identified in Item 4 do not meet the "significant" threshold for reporting under 10 CFR 76.9 (b). Provide more detail on: a) the events; b) the bases for those conclusions; c) the reason for not reporting these events in accordance with the Compliance Plans and 10 CFR 76.9 (b).
2.
Technical Safety Requirement (TSR) Limiting Condition for Operation (LCO) selection criteria in Section 4.2.3 specifies that " limiting" initiating events are considered for the five criteria for TSR LCOs. However, Figures 4.2 2 and 4.3-1 imply that any initiating event whose threshold analysis exceeds evaluation guidelines (EGs) were also screened for the TSR LCO criteria. Were non-limiting initiating events essential controls screened for TSR LCO selection?
3.
If not, were there non-limiting initiating events that had essential controls that met one of the five criteria listing in Section 4.2.3?
4.
Saction 4.3.2,1.3 c., " consequence analysis" for operational personnel in the Area Control Room (ACR) (page 4.3-47) refers to an evaluation that concluded adequate time was available for operators to perform required actions. Identify that evaluation.
5.
Section 4.3.2.1.5 d., " comparison with gu:delines"(page 4.3-53) notes that explosive concentrations of cascade gases could potentially result in a failure of the primary system.
TSR limits from USEC-01 and USEC-02 for preventing the explosive concentrations have been deleted in USEC SARUP. Provide more basis forjustifying deleting the TSR limits.
6.
Section 4.3.2.1.6, differs from POEF-LMES-89 in that the frequency was increased from Evaluation Basis Event (EBE) to Anticipated Event (AE) based on USEC SARUP not taking credit for cell coolant high pressure relief system. This was a limiting initiating event where a previous (USEC-01 and 02) TSR control has been deleted by accepting a higher frequency for the accident analysis. Provide further justification for why accepting c higher frequency for an analyzed accident is an acceptable basis for deleting a TSR control.
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2 7.
Section 4.3.2.2.2 a., " scenario description" identifies the 5% ullage as the ANSI limit that protects cylinders from hydraulic rupture when heated to normal autoclave temperatures.
Based on that scenario, a TSR safety limit for cylinders was identified. Other factors that protect the cylinder from hydraulic rupture such as fill limits and cold pressure checks were identified as administrative controls that were previous (USEC-01 and 02) TSR limits. The other factors appear to preserve initial conditions for an accident scenario that could have serious off site consequences. Provide furtherjustification for not identifying cold pressure checks and cylinder fill limits as TSR limits.
8.
Section 4.3.2.2.2, does not go into a source term nor consequence analysis based on a
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conclusion that t equate protection is available to prevent primary system failure. This is not consistent with the other limiting initiating events where similar conclusions still resulted in a source term and consequence analysis. Provide further justification or provide a source term and consequence analysis, 9.
Section 4.3.2.2.4, states a concem about transient events while the autoclave facility is evacuated and then states that four hours is a reasonable time frame to allow a retum time from a facility evacuation. Provide further bases for the four hour time frame with more detail about the nature of the transient events.
- 10. (PORTS only) Section 4.3.2.2.10 a., discusses administrative controls that prevent pigtail failure. One such controlis that cylinders are not rolled in an open autoclave unless visual contact is made during the rolling process. That practice has led to kinking of pigtails on 2.5 ton cylinders. The Paducah practice is to remove the pigtails before rolling. What operating constraints necessitate keeping the pigtails attached at PORTS resulting in possible challenges to the primary system integrity of the pigtails?
- 11. Section 4.3.2.2.10, states that past pigtail failures have identified administrative controls that make future events improbable and, therefore, the frequency of the analyzed accident is reduced to EBE (multiple personnel errors unlikely). Similar statements are made in the, drop cylinder scenario. In light of actual personnel performance, is the EBE event frequency a good assumption? What would be the results of an operational analysis of this scenario assumMg a higher frequency for this event?
- 12. Section 4.2.2.10 b., " source term analysis" assumes a 45 second release both for PORTS and Paducah. Paducah has an adomatic pigtailisolation system at the transfer station while PORTS relies on operator ac. ion. Why is the 45 second release time applicable to both sites?
- 13. Section 4.2.2.10 b., " source term analysis" relsase rates for Paducah and PORTS are the same even though there are identified differomes in system equipment that would call this into question. Provide more detail on the basis of the release rate. Examplos might include the assumed size of the daughter cylinders (2.5 ton cylinder would appear to be the size assumed but 10 ton cylinders are sometimes used at the X-344A at PORTS) and why different piping and pigtail diameters have the same release rate (most limiting chosen for both sites)?
- 14. Section 4.2.2.11 b., " source term analysis" assumes 45 second release rate based on 15 second detection and 30 second closure. The 30 second closure time is not captured in pigtailisolation TSR surveillance for the manual pigtail isolation checks. Provide basis.
- 15. (Paducah only) Paducah deleted the smoke detectors as a TSR LCO for the backup centrifugal compressors at Tails Withdrawal (USEC-01) from the TSR LCOs in the SARUP.
Provide basis.
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- 16. For Section 4.3.2.2.15, " Cylinder Failure OL,tside Autoclave," why is the cylinder high e
temperature steam cutoff identified as an essenti, control?
- 17. TSRs - many Certification TSR limits (safety limits, limiting control setting, tiraiting condition for operation, surveillance) have been deleted in the SARUP purportedly based on the new accident analysis. Specifically identify each TSR that was deleted in the PORTS and Paducah SARUP from USEC-01 and USEC-02 and the basis for deleting them. (Question 4 and 5 are exemples of questions arising from such deletions without adequa'e bases provided).
- 18. TSR 2.1.1 Operational Modes for the Cascade Facilities identifies the Mode " Controlled Feeding." initial Certification efforts identified that mode as an unanalyzed mode at Paducah. In addition, concems were raised by a hydraulic nioture of a feed line in December 1994 during such an evolution. It was determinec that the Controlled Feeding mode was unauthorized at Paducah until a basis for the mode was provided. Provide that basis.
- 19. TSR 2.1.3.1 and 2.1.3.2 for compressor motor trip and load identifies that the TSR is only applicable for "000" and "00" compressors. The smaller centrifugal compressors can have a hot metal reaction (see withdrawal station accident scenario). Are these comp.essors not considered for TSR application due to not being limiting initiating events (see question 1)?
Can they result in a telease that meets criteria 3 for TSR LCO selection?
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