Information Notice 2005-05, Improving Material Control and Accountability Interface with Criticality Safety Activities at Fuel Cycle Facilities
| ML050590234 | |
| Person / Time | |
|---|---|
| Issue date: | 03/10/2005 |
| Revision: | 0 |
| From: | Pierson R C NRC/NMSS/FCSS |
| To: | |
| References | |
| IN-05-005 | |
| Download: ML050590234 (5) | |
UNITED STATES NUCLEAR REGULATORY COMMISSIONOFFICE OF NUCLEAR MATERIAL SAFETY AND SAFEGUARDSWASHINGTON, DC 20555March 10, 2005NRC INFORMATION NOTICE 2005-05:IMPROVING MATERIAL CONTROL ANDACCOUNTABILITY INTERFACE WITH CRITICALITY SAFETY ACTIVITIES AT FUEL CYCLE FACILITIES
ADDRESSEES
All licensees authorized to possess a critical mass of special nuclear material.
PURPOSE
The U.S. Nuclear Regulatory Commission (NRC) is issuing this information notice (IN) to informaddressees of a safety concern related to criticality safety at fuel fabrication and other facilitiesprocessing, storing, or handling critical masses of fissile materia The safety concern arises when licensees fail to establish and maintain a communication process between criticality safety staff and material control and accountability (MC&A) staff, in order to support timelyidentification of fissile material-related process upsets that challenge the criticality safety basisfor the facilit It is expected that licensees will review this information and consider actions, asappropriate, to avoid similar problem Suggestions contained in this IN are not NRC requirements; therefore, no specific action nor written response is required.DESCRIPTION OF CIRCUMSTANCES Under 10 CFR Parts 70 and 76, certain licensees processing, storing, or handling criticalmasses of fissile material are required to analyze accident scenarios leading to criticality and provide reliable controls to assure that inadvertent criticality events are highly unlikely. Recently, a licensee reported an event, to the NRC, concerning operation of an incineratoroutside of the approved safety basi The licensee had performed a criticality safety evaluation of the incinerator approximately 8 years previously and had concluded that criticality was not credible outside of the primary combustion chambe The licensee nuclear criticality safety (NCS) analysis focused on accumulation of sufficientmass in the incinerator system to support criticalit Licensee NCS engineers concluded thatvery limited amounts of ash would carry over from the incinerator primary combustion chamber to the remainder of the incinerator system and that mass controls on the primary combustionchamber would limit uranium concentration in the ash to less than 21.6 percent throughout the incinerator syste This led the licensee's NCS engineers to conclude that criticality outsidethe primary combustion chamber was not credible due to normal operations and expected upsets. At the time that this NCS analysis was approved, licensee MC&A staff possessed samplingdata showing concentration levels above 21.6 percent uranium in some parts of the incinerator syste In addition, licensee MC&A staff were aware, from approximately 15 years ofoperational experience, that substantial amounts of fissile material routinely accumulated inparts of the incinerator system where criticality analysis assumed minimal accumulation.The material accumulation event was identified initially when a licensee criticality safetyengineer reviewed MC&A sampling dat Subsequent investigation of the event by the licenseerevealed that ash deposits at various locations in the incinerator routinely exceeded the 21.6 percent uranium concentration assumed to be bounding for ash and that the mass of ashdeposited also exceeded expectation Licensee review of MC&A sampling records confirmed that both concentration and deposit information were known prior to approval of the original NCS analysis.The amount of fissile material that accumulated in the uncontrolled parts of the incineratorsystem exceeded a critical mas Extensive investigation by the licensee and the NRCrevealed a poor interface between licensee criticality safety and MC&A staf This poor interface, resulting from failing to require routine interaction, apparently was a factor in the failure to identify the process upset before the event occurred.Discussion Two issues from this event are of concern to the NR The first issue is that licensee NCS staffhad not ensured that MC&A staff were familiar with the criticality safety basis for the incineratorsyste Specifically, MC&A staff were not aware of the basic assumption that fissile material would not accumulate in the upper chamber or flu Had MC&A staff been made aware of this assumption, they would likely have identified the reality of incinerator ash deposition and caused the NCS staff to place additional criticality controls on at least those two sections of the incinerator system.The second issue is that the MC&A sampling data routinely reported mass and concentrationvalues that challenged the criticality safety basis, and this fact was not recognized by criticality safety engineers because the data were not routinely provided to them.Licensee NCS staff are familiar with the criticality safety basis and underlying assumptions. MC&A staff have a general knowledge of where material is currently located and where process hold-up is likely to occu Communication between these two organizations is necessary to assure that the criticality safety basis is not violated.Failure to establish appropriate interactions between criticality safety and MC&A staff exposesfuel cycle licensees to this type of programmatic failur Licensees should consider actions, asappropriate, to mitigate this vulnerabilit NCS staff should be familiar with MC&A samplingmethodology and data reporting and should routinely review MC&A reports for location of material in relation to the criticality safety basi MC&A staff should be trained on the criticality safety basis, particularly bounding assumptions about fissile material accumulation, and shouldroutinely review new or changed NCS analyses.This IN requires no specific action nor written respons If you have any questions about theinformation in this notice, please contact the technical contact listed below./RA/Robert C. Pierson, DirectorDivision of Fuel Cycle Safety and Safeguards Office of Nuclear Material Safety and Safeguards
Technical Contact:
Dennis Morey, NMSS301-415-6107 e-mail: dcm@nrc.gov
Attachment:
List of Recently Issued NMSS Generic Communications safety basis, particularly bounding assumptions about fissile material accumulation, and shouldroutinely review new or changed NCS analyses.This IN requires no specific action nor written respons If you have questions about the information in this notice, please contact the technical contact listed below./RA/Robert C. Pierson, DirectorDivision of Fuel Cycle Safety and Safeguards Office of Nuclear Material Safety and Safeguards
Technical Contact:
Dennis Morey, NMSS301-415-6107 e-mail: dcm@nrc.gov
Attachment:
List of Recently Issued NMSS Generic ComminicationsML050590234OFCTSGFCFBTech EDTSGNSIRNAMEDMorey:dwJMuszkiewiczEkraus: by faxMGallowayMWilliamsDATE2/ 22 /053/ 01 /052/ 28 /052/ 28 /053/ 09 /05OFCFCSSNAMERPiersonDATE3/ 10 /05 Attachment Recently Issued NMSS Generic ComminicationsDateGC No.Subject
Addressees
12/16/2004RIS-04-020NRC Regulatory issueSummary 2004-20:
Lessons Learned from Review of 10 CFR Parts 71 and 72 ApplicationsAll holders of, and applicants for,a (1) 10 CFR Part 71 certificate of compliance for a radioactive material transportation package; (2) 10 CFR Part 72 cretificate of compliance for a spent fuel storage cask; and (3) 10 CFR Part 72 specific license for an independent spent fuel storage installation (ISFSI).12/01/2004RIS-04-018NRC Regulatory IssueSummary 2004-18:
Expiration Date for 10 CFR Part 71 Quality Assurance Program ApprovalsAll holders of U.S. NuclearRegulatory Commission (NRC)-approved 10 CFR Part 71 Quality Assurance Programs (QAPs).11/23/2004RIS-04-017NRC Regulatory IssueSummary 2004-17:
Revised Decay-in-Storage Provisions for the Storage of Radioactive Waste Containing Byproduct MaterialAll licensees regulated under 10CFR Parts 30, 32, 33, and 50.10/26/2004IN-04-018Recent Safety-RelatedEvent at Panoramic Wet-source-Storage IrradiatorAll licensees authorized to possess and use sealed sources in panoramic wet-source-storage irradiators, and irradiator vendors.07/19/2004IN-04-014Use of less than OptimalBounding Assumptions in Criticality Safety Analysis at Fuel Cycle FacilitiesAll licensees authorized topossess a critical mass of special nuclear material Note: NRC generic communications may be found on the NRC public website,http://www.nrc.gov, under Electronic Reading Room/Document Collections.