Information Notice 2007-30, Radiological Controls Create Criticality Safety Accident Scenario for Fissile Solution Container Transport at Fuel Cycle Facility
ML072500291 | |
Person / Time | |
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Issue date: | 09/13/2007 |
From: | Pierson R NRC/NMSS/FCSS |
To: | |
References | |
IN-07-030 | |
Download: ML072500291 (8) | |
UNITED STATES
NUCLEAR REGULATORY COMMISSION
OFFICE OF NUCLEAR MATERIAL SAFETY AND SAFEGUARDS
WASHINGTON, D.C. 20555 September 13, 2007 NRC INFORMATION NOTICE 2007-30: RADIOLOGICAL CONTROLS CREATE
CRITICALITY SAFETY ACCIDENT SCENARIO
FOR FISSILE SOLUTION CONTAINER
TRANSPORT AT FUEL CYCLE FACILITY
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 inform
addressees of a criticality safety concern regarding wrapping fissile solution filled vessels with
plastic, for radiological control, while transporting the vessels within fuel cycle facilities. NRC
expects that licensees will review this information and consider actions, as appropriate, to avoid
similar problems. Suggestions contained in this IN are not NRC requirements; therefore, no
specific action nor written response is required.
DESCRIPTION OF CIRCUMSTANCES
An NRC licensee operates a fuel cycle facility that processes and stores high-enriched uranium
(HEU) in both solid and solution form. To clean floors in contaminated areas of the facility, the
licensee typically places cleaning solution on the floor, scrubs the floor with an orbital scrubber, and then removes the solution with a large workshop-type vacuum cleaner. The vacuum
cleaners have a volume of approximately 52 liters (14 gallons) and are filled with raschig rings, to allow any solution in the facility to be vacuumed from the floor. The raschig ring-filled vacuum
cleaners are occasionally used to recover from large spills when collection of solution with
sponges would be too slow. Concentrated HEU solutions containing up to 400 grams per liter of
Uranium-235 (U-235) are allowed in raschig ring-filled vessels in the facility and such solutions
have been transferred into the raschig ring-filled vacuum cleaners.
The licensee uses forklifts to transport the raschig ring-filled vacuum cleaners to various
locations in the facility for floor cleaning. Most areas of the facility do not have equipment to
remove and process floor cleaning solutions, so the licensee transports filled vacuum cleaners
to another area to remove and process the contents. The licensee procedure for moving the
raschig ring-filled vacuum cleaners involved: (1) removing the vacuum pump; (2) covering the
vacuum cleaner vessel; (3) wrapping the vacuum cleaner vessel with two 55-gallon plastic bags;
and (4) moving the wrapped vacuum cleaner with a fork lift by means of brackets welded to the
vacuum cleaner frame (see Figure 1). Some of the raschig ring-filled vacuum cleaners in the
licensee facility had the lifting brackets, some did not have the brackets, and the lifting brackets
were not required to move the vacuum cleaners.
Figure 1 Rashig Ring-filled Vacuum Cleaner Vessel with Lifting Brackets
A raschig ring-filled vacuum cleaner was requested to be moved to a specified location for a
cleaning operation. The vacuum cleaner selected and wrapped for transport did not have the
lifting brackets. During the operation to move the vacuum cleaner without lifting brackets, a
licensee forklift operator picked up the vacuum with one forklift tine. The vacuum cleaner was
removed from one area and carried to another area while another licensee operator balanced
the vacuum cleaner on the single tine. At a doorway ramp near the destination, the vacuum
cleaner fell off the forklift. A large fraction of the raschig rings spilled from the vacuum cleaner
vessel and were retained by the inner wrapper. Most of the HEU solution in the vacuum cleaner
vessel, approximately 18 liters (5 gallons), spilled from the vessel and was captured between
the inner and outer wrappers, effectively separating the solution from the raschig rings. The
risk-significance of the resulting upset condition was low because the concentration of the HEU
solution was less than one gram per liter. Figure 2 Dropped Raschig Ring-filled Vacuum Cleaner Final Position
Figure 2 shows the position of the dropped vacuum cleaner vessel. The vessel is halfway up
the entrance ramp to the destination, with the top edge of the vessel lying at the edge of the
ramp. The raschig rings and solution have spilled from the vessel out over the edge of the ramp
which is approximately 3 to 4 inches high in that area. The double wrapped configuration and
the final resting position hanging over the edge of the ramp have combined to create an
unfavorable geometry vessel for the solution. Hanging downward allows a plastic bag or
wrapper to assume a more unfavorable geometry than would be likely if the final resting position
were a flat floor.
Subsequent investigation of the event revealed that: (1) no controls limited the concentration of
solution in the vacuum cleaners; (2) raschig ring-filled vacuum cleaners were commonly
transported while full of HEU solution; (3) licensee criticality safety staff did not routinely review
radiological control procedures; (4) licensee criticality safety staff were unaware that the vacuum
cleaners were transported while filled with solution; and (5) the licensee had not analyzed or
controlled the transport process with respect to criticality safety.
DISCUSSION
Licensee criticality safety engineers indicated that, had they known that the raschig ring-filled
vessels were being transported while filled with solution, they would have implemented controls
to limit the uranium content of the vessels. Such controls might have included placing limits on
solution concentration during transport, sampling the vessels before movement, or requiring a
specific transport configuration.
The NRC is concerned that licensees recognize and completely analyze all potential accident
sequences at their facilities. To this end, fuel cycle licensees typically require that criticality
safety staff review procedures associated with movement of fissile material, including
radiological control procedures.
The failure to review in-plant transport procedures and radiological controls can lead to the
creation of an unanticipated accident sequence. NRC criticality safety inspections typically
include review of the licensee criticality safety audit program, to ensure that analytical
assumptions are regularly reviewed in all areas. NRC criticality safety inspections routinely
review licensee facility operations to ensure that credible accident sequences have been
identified, analyzed, and controlled.
CONTACT
This information notice does not require any specific action or written response. Please direct
any questions about this matter to the technical contact below.
/RA/
Robert C. Pierson, Director
Division of Fuel Cycle Safety
and Safeguards
Office of Nuclear Material Safety
and Safeguards
Technical Contact:
Dennis Morey, NMSS
301-492-3112 E-mail: dcm@nrc.gov
Enclosure:
List of Recently Issued FSME/NMSS Generic Communications
DISCUSSION
Licensee criticality safety engineers indicated that, had they known that the raschig ring-filled
vessels were being transported while filled with solution, they would have implemented controls
to limit the uranium content of the vessels. Such controls might have included placing limits on
solution concentration during transport, sampling the vessels before movement, or requiring a
specific transport configuration.
The NRC is concerned that licensees recognize and completely analyze all potential accident
sequences at their facilities. To this end, fuel cycle licensees typically require that criticality
safety staff review procedures associated with movement of fissile material, including
radiological control procedures.
The failure to review in-plant transport procedures and radiological controls can lead to the
creation of an unanticipated accident sequence. NRC criticality safety inspections typically
include review of the licensee criticality safety audit program, to ensure that analytical
assumptions are regularly reviewed in all areas. NRC criticality safety inspections routinely
review licensee facility operations to ensure that credible accident sequences have been
identified, analyzed, and controlled.
CONTACT
This information notice does not require any specific action or written response. Please direct
any questions about this matter to the technical contact below.
/RA/
Robert C. Pierson, Director
Division of Fuel Cycle Safety
and Safeguards
Office of Nuclear Material Safety
and Safeguards
Technical Contact:
Dennis Morey, NMSS
301-492-3112 E-mail: dcm@nrc.gov
Enclosure:
List of Recently Issued FSME/NMSS Generic Communications
ML072500291 OFC FSCC/TSB Tech ED FSME FCSS/TSB FCSS FCSS
NAME DMorey Ekraus: fax AMcIntosh DJackson JGiitter RPierson
DATE 9/ 7 /07 9/ 6 /07 9/ 7 /07 9/ 11 /07 9/ 11 /07 9/ 13 /07 OFFICIAL RECORD COPY Recently Issued FSME/NMSS Generic Communications
Date GC No. Subject
Addressees
02/02/07 IN-07-03 Reportable Medical Events Involving All U.S. Nuclear Regulatory Commission
Patients Receiving Dosages of medical use licensees and NRC Master
Sodium Iodide Iodine-131 less than Materials Licensees. All Agreement State
the Prescribed Dosage Because of Radiation Control Program Directors and
Capsules Remaining in Vials after State Liaison Officers.
Administration
02/28/07 IN-07-08 Potential Vulnerabilities of Time- All U. S. Nuclear Regulatory Commission
reliant Computer-based Systems licensees and all Agreement State
Due to Change in Daylight Saving Radiation Control Program Directors and
Time Dates State Liaison Officers.
03/13/07 IN-07-10 Yttrium-90 Theraspheres and All U.S. Nuclear Regulatory Commission
Sirspheres Impurities (NRC) Medical Licensees and NRC Master
Materials Licensees. All Agreement State
Radiation Control Program Directors and
State Liaison Officers.
04/04/07 IN-07-13 Use of As-Found Conditions to All licensees authorized to possess a
Evaluate Criticality-related Process critical mass of special nuclear material.
Upsets at Fuel Cycle Facilities
05/02/07 IN-07-16 Common Violations of the Increased All licensees who are implementing the
Controls Requirements and Related U.S. Nuclear Regulatory Commission
Guidance Documents (NRC) Order Imposing Increased Controls
(EA-05-090), issued November 14, 2005 and December 22, 2005.
05/21/07 IN-07-19 Fire Protection Equipment Recalls All holders of operating licenses for nuclear
and Counterfeit Notices power reactors and fuel cycle facilities;
except those licensees for reactors that
have permanently ceased operations and
who have certified that fuel has been
permanently removed from the reactor
vessel; and except those licensees for
decommissioned fuel cycle facilities.
06/11/07 IN-07-20 Use of Blank Ammunition All power reactors, Category I fuel cycle
facilities, independent spent fuel storage
installations, conversion facility, and
gaseous diffusion plants. Date GC No. Subject
Addressees
IN-07-23 Inadvertent Discharge of Halon All holders of operating licenses for nuclear
1301Fire-suppression System from power reactors, except those who have
Incorrect and/or Out-of-date permanently ended operations and have
Procedures certified that fuel has been permanently
removed from the reactor vessel. All
holders of licenses for fuel cycle facilities.
07/19/07 IN-07-25 Suggestions from the Advisory All U.S. Nuclear Regulatory Commission
Committee on the Medical Use of (NRC) medical-use licensees and NRC
Isotopes For Consideration to Master Materials Licensees. All Agreement
Improve Compliance With Sodium State Radiation Control Program Directors
Iodide I-131 Written Directive and State Liaison Officers.
Requirements in 10 CFR 35.40 and
Supervision Requirements in 10
CFR 35.27
08/13/07 IN-07-26 Combustibility of Epoxy Floor All holders of operating licenses for nuclear
Coatings at Commercial Nuclear power reactors and fuel cycle facilities
Power Plants except licensees for reactors that have
permanently ceased operations and who
have certified that fuel has been
permanently removed from the reactor
vessel.
03/01/07 RIS-07-03 Ionizing Radiation Warning Symbol All U.S. Nuclear Regulatory Commission
licensees and certificate holders. All
Radiation Control Program Directors and
State Liaison Officers
03/09/07 RIS-07-04 Personally Identifiable Information All holders of operating licenses for nuclear
Submitted to the U.S. Nuclear power reactors and holders of and
Regulatory Commission applicants for certificates for reactor
designs. All licensees, certificate holders, applicants, and other entities subject to
regulation by the U.S. Nuclear Regulatory
Commission (NRC) of the use of source, byproduct, and special nuclear material
03/20/07 RIS-07-05 Status and Plans for Implementation All NRC materials licensees, Radiation
of NRC Regulatory Authority for Control Program Directors, State Liaison
Certain Naturally-occurring and Officers, and NRCs Advisory Committee
Accelerator-produced Radioactive on the Medical Uses of Isotopes
Material
04/05/07 RIS-07-07 Clarification of Increased Controls All U.S. Nuclear Regulatory Commission
for Licensees That Possess (NRC) licensees issued NRCs Order
Collocated Radioactive Material Imposing Increased Controls and all
During Transportation Activities Radiation Control Program Directors and
State Liaison Officers Date GC No. Subject
Addressees
05/04/07 RIS-07-09 Examples of Recurring Requests for All holders of, and applicants for, a: (1) 10
Additional Information (RAIs) for 10 CFR Part 71 certificate of compliance
CFR Part 71 and 72 Applications (CoC) for a radioactive material
transportation package; (2) 10 CFR Part 72 CoC for a spent fuel storage cask; and (3)
10 CFR Part 72 specific license for an
independent spent fuel storage installation
(ISFSI).
06/27/07 RIS-06-27, Availability of NRC 313A Series of All U.S. Nuclear Regulatory Commission
Suppl. 1 Forms and Guidance for Their (NRC) medical-use licensees and NRC
Completion Master Materials licensees. All Radiation
Control Program Directors and State
Liaison Officers.
05/15/07 RIS-07-10 Subscriptions To New List Server
For Automatic Notifications Of All U.S. Nuclear Regulatory Commission
Medical-Related Generic (NRC) medical-use licensees and NRC
Communications, Federal Register Master Materials licensees. All Radiation
Notices And Newsletters Control Program Directors and State
Liaison Officers.
Note: A full listing of generic communications may be viewed at the NRC public website at the following address:
http://www.nrc.gov/Electronic Reading Room/Document Collections/Generic Communications