ML20126K644
| ML20126K644 | |
| Person / Time | |
|---|---|
| Site: | Framatome ANP Richland |
| Issue date: | 01/04/1993 |
| From: | Maas L SIEMENS POWER CORP. (FORMERLY SIEMENS NUCLEAR POWER |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9301070203 | |
| Download: ML20126K644 (3) | |
Text
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5SIEMENS January 4,1993 U.S. Nuclear Regulatory Comm!ssion Attn: Document Control Desk Washington, DC 20555
Subject:
Reply to Notice of Violation Ref:. Letter, R. A. Scarano to Siemens Power Corporation, "NRC Inspection Report No. 70-1257/92-08," dated December 4,1992.
Gentlemen:
Enclosed is Siemens Power Corporation's reply to the Notice of Violation transmitted to SPC by the referenced letter. If you have any questions regarding this reply, please contact me at 509-375-8537.
Very)truly yours, i
Ot%
WJ Loren J. Maas, Manager Regulatory Compliance LJM:pm cc:
Mr. John B. Martin Region V Administrator 9l004' Siemens Power Corporation Nuclear Division Engineering and Manufacturing Facility f'
2101 Horn Rapids Road, PO Box 130 Richland, WA 99352-0130 Tel: (509) 3754100 Fax: (509) 37 I402 -
~9301070203_930104
.PDR-ADDCK 07001257 9.
PDR:
USNRC Document Control Desk January 4,1993 Page1 Slemens Power Corporation (SPC) Reply to Notice of Violation Dated December 4,1992 (NRC Inspection Report No,70-1257/92-08)
Violation 1 CSA U 1.2, dated August 1973 (for the Line 1 vaporization chests), was not adequate to determine that criticality safety critoria were satisfied, in that the CSA failed to incorporate all credible accident conditions, thus failing to adequately determine that no single condition was capable of causing an accidental criticality. Specifically, flooding of uranium hexafluoride vaporization chests (unfavorable geometry vessels), with uranium bearing solutions from process systems that vented to the connecting process off gas (POG) system was a credible accident condition that was not analyzed in the CSA. On October 13,1992, such an event occurred when a process tank containing low enriched (4.0 percent U-235) uranyl fluorlde overflowed to the POG system and into an unfavorable geometry vaporization chest, a credible accident.
SPC Respor,se to Violation SPC admits to this violation.
Reason for Violatiort The reason for the deficiency in CSA U-1.2 was a failure to sufficiently predict systems interactions in identifying and analyzing credible accident scenarios.
Immediate Corrective Actio_ns The following actions were taken in the short term to correct the conditions that caused the tank 10 overflow, to assure a complete identification of credible accident scenarios, and to update the associated CSAs to reflect all necessary controls.
Conversion line 1 was immediately shut down and conversion line 2 was put on standby. Upon being notified of the event, Safety, Security, and Licensing notified NRC under Bulletin 91-01, The following day (October 14) NRC Region V issued a Confirmatory Action Letter specifying conditions that would need to be met to the satisfaction of NRC Region V prior to conversion line restart.
An incident investigation Board (llB) was convened to coordinate and oversee a thorough investigation of the event, to identify the potential for similar events in the other conversion line, and to specify the corrective actions to preclude such events.
A criticality safety calculation was performed to assess consequences of this event under worst case conditions of maximum solution concentration and l
'O USNRC Document Control Desk January 4,1993 Page 2 depth of solution in the vaporization chest. The calculation showod that the system would romain sub-critical by a substantial margin.
An independent task force was assembled to ovaluate the potent'al for similar l
accidents throughout the chemical processing area and to take appropriate correctivo actions.
Addenda were prepared to CSAs U 1.2, U-1.7, and U-1.26 to reflect additional accident scenarios and related criticality safety controls.
The Startup Council was convened to review the adequacy of the completed corrective actions prior to restarting the conversion lines. Startup approval from the council was granted on October 22. NRC concurrence, i.e.
notification that requirements of the Confirmatory Action Letter had been met, was received on October 23.
Corroctivo Action to Avoid Further Violations-Based on an earlier criticality safety occurrence and resulting NRC inspection (NRC Inspection Report No. 701257/92-06) as well as subsequent internal ovaluation, SPC had already committed to NRC Region V (NRC Enforcement Conference, Sept. 22,1992, Walnut Crook) to undertake a major program to review the accuracy, adoquacy and consistency of all criticality safety analyses and sub-tier documents.- This program, reviewed with NRC-Region V staff and outlined in a program plan submittod by B. N.' Femreite'(SPC Richland Plant Manager) to J. B. Martin (NRC Region V Administrator) on December 30,1992, will ^
include a validation of existing CSA assumptions, revision of CSAs as required (reformatting, enhancing, or reanalyzing), followed by an updating of implementing documentation (Criticality Safety Specifications and Operating Procedures). - A copy of this program was also sont to the Director of the Offico of Enforcement.
Dato to be in Full Compliance The immediate corrective actions to preclude recurrence of this event and to remedy the deficient CSA have been completed. The major CSA update program, discussed in the above paragraph, has been initiated.- A projected schedule for completion is included with the program description.
Violation 2 Violation 2 addressed deficiencies in SPC's evaluation of the event for reportability and failure to report in conformance with internal reporting requirements.- NRC's evaluation of corrective actions submitted by SPC in response to the Confirmatory Action Letter indicated that SPC had corrected this matter. The Notice of Violation indicated that no further written response was required.