Information Notice 1999-30, Failure of Double Contingency Based on Administrative Controls Involving Laboratory Sampling and Spectroscopic Analysis of Wet Uranium Waste
| ML993060157 | |
| Person / Time | |
|---|---|
| Issue date: | 11/08/1999 |
| From: | TenEyck E Q NRC/NMSS/FCSS |
| To: | |
| Ten-Eyck E Q | |
| References | |
| IN-99-030 | |
| Download: ML993060157 (7) | |
UNITED STATES
NUCLEAR REGULATORY
COMMISSION
OFFICE OF NUCLEAR MATERIAL
SAFETY AND SAFEGUARDS
D.C. 20555 November 8, 1999 NRC INFORMATION
NOTICE NO. 99-30: FAILURE Of DOUBLE CONTINGENCY BASED
ON ADMlNlSTRATlVE
CONTROLS INVOLVING
LABORATORY
SAMPLING AND SPECTROSCOPIC ANALYSIS OF WET URANIUM
WASTE
Addressees
All fuel cycle licensees
and certificants
performing laboratory analysis
to determine uranium
content, in support of administrative criticality safety
controls.
Purpose
- The U.S. Nuclear Regulatory
Commission (NRC) is issuing this information
notice to alert addressees
to problems recently noted
with the laboratory and spectroscopic
analysis of uranium contaminated
material.
Under certain conditions, incomplete dissolution
of samples may produce a nonconsewative laboratory result and
lead to violation
of criticality safety
limits. When the laboratory
sampling is backed up by spectroscopic analysis, care must be taken to ensure a sufficiently
precise result through proper
qualification
of the spectroscopic method.
Recipients
are expected to review this information for applicability
to their facilities and consider
actions, as appropriate, to avoid similar problems. Suggestions contained in this information
notice are not NRC requirements. Therefore, no specific action nor written
response is required.
Descri~tion
of Circumstances:
On August 12, 1999, a fuel cycle licensee determined
that a laboratory dissolution process
was not completely dissolving the
uranium in certain samples, which resulted in underestimating
the amount of uranium in wet process waste. Subsequent
licensee gamma spectroscopic
analysis of the wet waste also failed to detect the problem, because of inadequate
spectroscopic
analysis conditions.
Because of these simultaneous failures, excessive uranium was transferred
into the wet process waste storage arrays. These deficiencies
in sampling and spectroscopic
analysis of process waste
degraded the margin of safety to the
extent that a criticality
safety limit was violated.
IN 99-30 November 8, 1999 Discussion:
On July 30, 1999, a fuel cycle licensee discovered that a combustible
waste bag containing
laboratory
filter paper had higher than expected radiation
readings.
A subsequent licensee
investigation
revealed that the acid leach dissolution process used
to prepare samples for analysis of uranium content had not completely dissolved
the uranium. When the samples were later filtered during the
sample preparation
process, some uranium was deposited on the
filter paper with other solids. The samples in
question came from
a uranium recovery process that produced wet solid
waste that was collected into
5-gallon buckets and stored in
a safe, single-layer
array. The samples were used to determine
uranium content before the material was further collected
into 55-galon drums. Once the waste was
collected into the 55-gallon drums, the drums
were examined by spectroscopic
analysis before being stored in a safe, triple-layer array.
The licensee investigation revealed that
the 55-gallon drum spectroscopic
analysis was also assigning a
low value to the uranium content of the drums. This was because the drum catibration
standard did not adequately
resemble the material being
counted and the spectroscopic
analysis did not account
for self-shielding
in the drum material.
The licensee had completed
a criticality
safety anatysis (CSA) of the tripte-layer
drum storage array to establish safety parameters.
The analysis made use of the surface density method to establish
the maximum uranium content limit for
individual drums. Double
contingency
for the storage array was maintained through sampling of the 5-gallon buckets and
spectroscopic
analysis of the 55-gallon
drums. As a result of
these independent and simultaneous failures, drums stored in the array exceeded the
maximum allowed uranium content
for single drums by up to 32%, thereby causing the failure of the double-contingency arrangement.
This situation was safety significant in
that no controls remained to
limit the mass in the array, although
the total mass
involved was far less than
what would be required for a criticality.
An important
contributing
factor in this event was the limited
scope of the wet waste material
process CSA, which stopped with the material being placed into 5-gallon buckets and did
not overlap the CSA covering the 55-gallon
drum storage. Including the
transfer from 5-gallon buckets to 55-gallon
drums in the wet waste material CSA should have
resulted in more robust controls such as a requirement
for dual sampling before permitting the
transfer.
An additional
important
contributing
factor in this event was that the sample processing
procedures allowed a
choice of dissolution methods under the assumption that either
dissolution
method would produce a substantially
similar result. The procedure writers mistakenly assumed that the
acid leach dissoiution
method of sample preparation would
put all uranium into
solution even if the entire sample
was not dissolved.
Finally, the spectroscopic analysis
procedures
did not qualify waste streams
for spectroscopic analysis, ensure optimal packaging for
spectroscopic
analysis, or require corrective
action, when spectroscopic
analysis results did
not support laboratory analysis. Spectroscopic
analysis
IN 99-30 November 8, 1999 of the 55-gallon
drums failed to
detect the drums containing
excess uranium due to these
failures.
ANSI N15.20-1975 "Guide to
Calibrating Nondestructive Assay Systems" provides
a more complete discussion
of spectroscopic
analysis sensitivities.
This event highlights
the necessity
for careful review of administrative controls, to ensure that
the failure of such controls is actualty unlikely.
tn addition, CSAs need to be broad enough that the analyst will clearly understand the safety significance
of proposed controls. All
procedures
having an impact on the control need
to be reviewed carefully
to ensure that the control is
actually implemented.
It is expected that addressees
will evaluate the
above information for
applicability
to licensed activities.
This information
notice requires no specific actions nor written
response.
If you have any questions
about the information in
this notice, please contact the technical
contact listed below or the appropriate
regionai office. ck, Ap Dire ~ivi$on of ~uel Cycle Safety and Safeguards
Office of Nuclear Material Safety and Safeguards
Technical Contact:
Dennis
C. Morey, NMSS 301 -41 5-61 07 E-mail: dcm~nrc.gov
Attachments:
1. List of Recently Issued MMSS Information
Notices 2. List of Recently issued NRG Information
Notices
Attachment
I IN 99-30 November 1 1, 1999 LIST OF RECENTLY ISSUED NMSS INFORMATION
NOTICES Information
Date of Notice No. Subject Issuance Issued to
99-29 Authorized
Contents of Spent 10128199 All power reactor licensees
and Fuel Casks spent fuel
storage licensees
and applicants
99-28 Recall of Star Brand Fire 913Oig9 Alt holders of licenses for nuclear Protection Sprinkler
Heads power, research and test reactors, and fuel cycle facilities
99-27 Malfunction
of Source Retraction
9/2/99 All medical licensees authorized
Mechanism in Cobalt-60
Teletherapy
to conduct teletherapy
treatments Treatment Units
99-26 Safety and
Economic 8/24/99 All Distributors
andlor Consequences
of Misleading
Manufacturers
of Generally
Marketing
Information
Licensed Products 99-24 Broad-Scope
Licensees'
711 2/99 All medical
licensees'
of broad- Responsibilities
for Reviewing
and scope and master materials
Approving Unregistered Sealed
ticensees
Sources and Devices Safety Concerns Related To Repeated Control
Unit Failures of the Nucletron
Ciassic Model High-Dose-Rate
Remote Afterloading
Devices ?O CFR 34.43(a)(I):
Effective
6/25/99 Date for Radiographer Certification
and Plans for Enforcement
Discretion
Contingency
Planning for the 612 519 9 Year 2000 Computer Problem
Update on NRC's Year 2000 611 4199 Activities for Materials Licensees
and Fuel Cycle Licensees
and Certificate Holders Federal Bureau of Investigation's
5/28/99 Nuclear Site Security Program
All U.S. NRC medical licensees
authorized to use brackytherapy
sources in Nucletron Classic
Model high-dose-rate ((HDR) remote afterloaders
Industrial Radiography Licensees All material
and fuel cycle licensees
and certificate holders
All material and fuel cycle
licensees
and certificate
holders A11 US. Nuclear Regulatory Commission fuel cycle, power
reactor, and non-power
reactor licensees
Attachment
2 IN 99-30 November 2 I, 1999 Page 1 of l LIST OF RECENTLY ISSUED NRC INFORMATION NOTICES
Information
Date of Notice No.
Subject Issuance Issued to
99-29 Authorized
Contents of Spent 10/28/99 All power reactor licensees
and Fuel Casks spent fuel storage licensees
and applicants
Recall of Star Brand Fire Protection
Sprinkler
Heads All holders of licenses for
nuclear power, research, and test reactors, and fuel cyde facilities
Malfunction of Source
Retraction
9/2/99 All medical licensees authorized Mechanism in
Cobalt-60
Teletherapy
to conduct teletherapy treatments
Treatment
Units Safety and Economic 8/24/99 Consequences of
Misleading
Marketing
Information Year 2000 Contingency Planning
8/10/99 Activities
Broad-Scope
Licensees'
7/2 2/99 Responsibilities for Reviewing
and Approving
Unregistered
Sealed Sources and Devices Safety Concerns Related
To 7/6/99 Repeated Control Unit
Failures of the Nucletron
Classic Model High-Dose-Rate
Remote Aferloading
Devices 10 CFR 34.43{a)(l);
Effective
7/6/99 Date for Radiographer
Certification
and Plans for
Enforcement
Discretion All Distributors
and/or Manufacturers of Generally
Licensed Products All holders of operating
licenses for nuclear power plants and fuel cycle facilities
All medical licensees
of broad- scope and master materials
licensees
All U.S. NRC medical licensees
authorized to use brachytherapy
sources in Nudetron Classic Model high-dose-rate (HDR) remote afterloaders Industrial Radiography
Licensees
OL = Operating
License CP = Construction
Permit
IN 99-30 November 8, 1999 of the 55-gallon drums failed
to detect the
drums containing
excess uranium due to these failures.
ANSI N15.20-1975 "Guide to Calibrating
Nondestructive
Assay Systems" provides a more complete discussion
of spectroscopic analysis sensitivities.
This event highlights the
necessity for careful review of
administrative
controls, to ensure
that the failure of such controls is actually unlikely.
In addition, CSAs need to be broad enough
that the analyst will clearly
understand
the safety significance of proposed controls.
All procedures
having an impact
on the control need
to be reviewed carefully
to ensure that
the control is actually implemented.
It is expected that addressees will
evaluate the above information for applicability
to licensed activities.
This information notice requires no specific actions nor written
response.
If you have any questions about the information in this notice, please contact the
technical contact listed
below or the appropriate regional office.
Elizabeth
Q. Ten Eyck, Director Division of Fuel Cycle Safety and Safeguards
Office of Nuclear Material
Safety and Safeguards
Technical
Contact: Dennis C. Morey, NMSS 301-415-6107 E-mail: dcm@nrc.gov
Attachments:
1. List of Recently Issued
NMSS Information
Notices 2. List of Recently Issued NRC lnformation
Notices FtLE NAME: a:\99-30.in
- See ~revious concurrences
C = COVER E = COVER & ENCLOSURE
OFFICIAL RECORD COPY N = NO COPY
P .: s IN 99-xxx , 1999 It is expected that
addressees will evaluate the
above information
for applicability
to licensed activities.
This information notice requires no specific actions nor written response. If you have any questions
about the information
in this notice, please
contact the tdchnical
contact listed below or the
appropriate
regional office. 1 i i i i r' Elizabeth
Q. Ten ~~~k, Director Division of Fuel
Cyqle Safety and Safeguards
/ Office of Nuclear ,Material
Safety and safeguards
i Technical
Contact: Dennis C. Morey, NMSS 301-475-6107 i it E-mail: dcm@nrc.gov
/ i' ,/' Attachments:
i 1. List of Recently Issued NMSS
lnformation
~oticed 2. List of Recently lssued NRC information
Notice,$ ./ i /' C = COVER ' E = COVER & ENCLOSURE
1' OFFICIAL RECORD COPY FILE NAME: a:\fNsiernenl.wpd ,l / C N = NO COPY o FC TECH ED FCOB NAME EKrauss I DMorqh >\'8/pbSM'~ink
DATE 1 199 /!kg9 .A is9 I oi,jigg 0 FC$B / KK&z?zf KnE! ~$99 1 1~99 I / /' FCOS 6 IMNS