Information Notice 1999-31, Operational Controls to Guard Against Inadventent Nuclear Criticality
| ML993140347 | |
| Person / Time | |
|---|---|
| Issue date: | 11/17/1999 |
| From: | Teneyck E NRC/NMSS/FCSS |
| To: | |
| Ten-Eyck E | |
| References | |
| IN-99-031 | |
| Download: ML993140347 (4) | |
UNITED STATES
NUCLEAR REGULATORY COMMISSION
OFFICE OF NUCLEAR REACTOR REGULATION
WASHINGTON, D.C. 20555-0001
November 1 7, 1999
NRC INFORMATION NOTICE NO. 99-31 : OPERATIONAL CONTROLS TO GUARD
AGAINST INADVERTENT NUCLEAR
CRITICALITY
Addressees
All NRC licensed fuel cycle conversion, enrichment and fabrication facilities.
Purpose
The U.S. Nuclear Regulatory Commission (NRC) is issuing this Inf~rmation Notice (IN) to alert
addressees to a recent nuclear criticality accident at a foreign fuel fabrication facility that
resulted in a significant radiation exposure to workers and members of the public. Although an
evaluation of the impact of this accident is ongoing, the NRC expects that recipients of this IN
will review the information for applicability to their facilities and consider actions, as appropriate, to protect against a similar occurrence. However, suggestions contained in this IN are not
NRC requirements. Therefore, no specific action nor written response to this notice is required.
Descri~tion of Circumstances
On September 30, 1999, a nuclear criticality accident occurred at a facility in Japan that
preliminary information indicates resulted in the exposure of three operators to extremely high
levels of radiation, the extensive contamination of process areas, exposure of emergency
responders and members of the public, and contamination of the environment. Preliminary
indications are that the accident involved the dissolution of about 5 times the safe mass of
uranium oxide (enriched to about 18%) by nitric acid in an "unfavorable" geometry vessel (i.e.,
the vessel was not designed to preclude a criticality for the enrichments involved). The 18%
enriched process was just restarted after a several year shutdown.
Discussion
The Government of Japan has initiated a formal task force headed by the Prime Minister to
thoroughly investigate the causes of the accident and determine any potential criminal liability.
As information becomes available from the Government of Japan, NRC plans to conduct an in- depth review of the details surrounding the event to determine whether further improvements in
the NRC regulatory program would be prudent. In the interim, a Temporary Instruction has
been issued to NRC Resident Inspectors at the two high enriched uranium (HEU) facilities and
the two gaseous diffusion plants regulated by NRC to focus inspection resources on criticality
safety implementation at these facilities. NRC also plans to review the results of an industry
initiative to assess their criticality programs. In view of the above accident, licensees are
encouraged to review their policies and procedures and the results of safety assessments to
assure that:
IN 99-31 November 17,1999 Page 2 of 2
1. The possibility of commingling HEU and low enriched uranium (LEU) has been
considered, where applicable, and appropriately rigorous controls are established to
prevent the inadvertent introduction of HEU material into LEU plant areas and
processes.
2. Operators who are authorized to handle special nuclear material (SNM) have received
proper traininglretraining with regard to the criticality safety rules and postings and that
they understand the significance of the operating limits and what their expected
response should be if any operating limit is exceeded.
3. Operations are conducted and administrative safety controls are implemented only in
accordance with approved operating procedures and postings.
4. New processes and restart of processes that have been shut down for an extended .
period of time are covered by current safety assessments and an administrative process
confirms that all applicable controls are established and implemented and operator
traininglretraining is completed prior to the introduction of SNM into the process.
5. Emergency plans contain appropriate provisions to ensure that both onsite and offsite
emergency response personnel are made aware of criticality safety aspects of the
facility, and receive proper health physics coverage and protection when responding to
plant events.
6. Management provides an appropriate level of oversight of high risk operations to ensure
that plant safety programs are effectively implemented and management expectations
are being met.
Any further information developed as a result of the Japanese investigation will be reviewed by
NRC to determine whether further action may be warranted.
This IN requires no specific action nor written response. If you have any questions about the
information in this notice, please contact the technical contact listed below, or the appropriate
NRC regional office.
Elizabeth Ten Eyck, Director
Division of Fuel Cycle Safety
and Safeguards
Office of Nuclear Material Safety
and Safeguards
Technical contact: William Troskoski, NMSS
30 1 -4 1 5-8076 E-mail:wmt@nrc.qov
Attachments:
1. List of Recently Issued NMSS lnformation Notices
2. List of Recently Issued NRC lnformation Notices
Attachment 1 IN 99-31 November 17, 1999 Page 1 of 1
LIST OF RECENTLY ISSUED
NMSS INFORMATION NOTICES
Information Date of
Notice No. Subject Issuance Issued to
99-30 Failure of Double Contingency 11/8/99 All fuel cycle licensees and
Based on Administrative certificates performing laboratory
Controls Involving Laboratory analysis to determine uranium
Sampling and Spectroscopic content, in support of
Analysis of Wet Uranium administrative criticality safety
Waste controls
Authorized Contents of Spent I 0/28/99 All power reactor licensees and
Fuel Casks spent fuel storage licensees and
applicants
Recall of Star Brand Fire 9/30/99 All holders of licenses for nuclear
Protection Sprinkler Heads power, research and test
reactors, and fuel cycle facilities
Malfunction of Source All medical licensees authorized
Retraction Mechanism in to conduct teletherapy treatments
Cobalt-60 Teletherapy
Treatment Units
Safety and Economic 8/24/99 All Distributors andlor
Consequences of Misleading Manufacturers of Generally
Marketing lnformation Licensed Products
Broad-Scope Licensees' 711 2/99 All medical licensees' of broad- Responsibilities for Reviewing scope and master materials.
and Approving Unregistered licensees
Sealed Sources and Devices
Safety Concerns Related to 7/6/99 All U. S. NRC medical licensees
Related Control Unit Failures authorized to use brachytherapy
of the Nucletron Classic Model sources in Nucletron Classic
High-Dose-Rate Remote Model high-dose-rate remote
Afterloading Brachytherapy afterloaders
Devices
99-22 10 CFR 34.43(a)(I ); Effective 6/25/99 Industrial Radiography Licensees
Date for Radiographer
Certification and Plans for
Contingency Planning for the 6/25/99 All material and fuel cycle
Year 200 Computer Problem licensees and certificate holders
Attachment 2 IN 99-31 November 17,1999 Page 1 of 1
LIST OF RECENTLY ISSUED
NRC INFORMATION NOTICES
lnformation Date of
Notice No. Subject Issuance Issued to
99-30 Failure of Double Contingency 1 1 18/99 All fuel cycle licensees and
Based on Administrative Controls certificates performing laboratory
Involving Laboratory Sampling and analysis to determine uranium
Spectroscopic Analysis of Wet content, in support of
Uranium Waste administrative criticality safety
controls
Authorized Contents of Spent 10128199 All power reactor licensees and
.Fuel Casks spent fuel storage licensees and
applicants
Recall of Star Brand Fire 9130199 All holders of licenses for nuclear
Protection Sprinkler Heads power, research, and test
reactors, and fuel cycle facilities
Malfunction of Source Retraction 912199 All medical licensees authorized
Mechanism in Cobalt-60 Teletherapy to conduct teletherapy treatments
Treatment Units
Safety and Economic 8124199 All Distributors andlor
Consequences of Misleading Manufacturers of Generally
Marketing lnformation Licensed Products
Year 2000 Contingency Planning 811 0199 All holders of operating licenses
Activities for nuclear power plants and fuel
cycle facilities
Broad-Scope Licensees' 711 2/99 All medical licensees of broad- Responsibilities for Reviewing scope and master materials
and Approving Unregistered licensees
Sealed Sources and Devices
OL = Operating License
CP = Construction Permit