Lessons Learned From Incidents. · Sealed Source & Device Workshop Lessons Learned: 2. Types of...

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Lessons Learned From Incidents

Transcript of Lessons Learned From Incidents. · Sealed Source & Device Workshop Lessons Learned: 2. Types of...

Page 1: Lessons Learned From Incidents. · Sealed Source & Device Workshop Lessons Learned: 2. Types of Incidents/Causes Mechanical Computer Human Licensing/Regulatory ... Events Database

Lessons Learned

From Incidents

Page 2: Lessons Learned From Incidents. · Sealed Source & Device Workshop Lessons Learned: 2. Types of Incidents/Causes Mechanical Computer Human Licensing/Regulatory ... Events Database

What is an Incident?

Incident - an undesirable and/or abnormal occurrence involving byproduct material.

We receive reports through:

- Regulations - Parts 20, 21, 30, 31, 34, 35, and 36.

- During Inspections

- “Oh, by the Way”

Sealed Source & Device Workshop Lessons Learned: 2

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Types of Incidents/Causes

Mechanical

Computer

HHuman

Licensing/Regulatory

Design

Quality Control

Sealed Source & Device Workshop Lessons Learned: 3

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Extent of the Incident

Concerns a Specific User or Product

Concerns a Specific Product Design

Concerns a Specific Manufacturer

Concerns a Specific Class of Product

Truly Generic - Design, Material

Sealed Source & Device Workshop Lessons Learned: 4

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General ObservationsIndustrial Gauges- Air Quality, Corrosion, Return Springs- Mountings (vibration, torque on straps, vibration,

incorrectly installed)- Loss of Shielding

Radiography- Lock Failure- Connector Failure- Corrosion- Wrong Lubricant (e.g., WD-40)- Worn S-Tube- Incompatible Equipment

Sealed Source & Device Workshop Lessons Learned: 5

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General Observations (cont.)Irradiators- Poor Design and Maintenance of Sources- Cesium-137- Transportation Affects- Source Rack FailuresSource Rack Failures

Brachytherapy- Computer Errors- Failed Source Retraction- Broken Source Wire- Wrong Treatment Site or Time of Exposure

Sealed Source & Device Workshop Lessons Learned: 6

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Communications

Generic Communications

Newsletters, Workshops, NUREGs, SRPs

Recalls

Sealed Source & Device Workshop Lessons Learned: 7

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Nuclear MaterialEvents Database

NMED: http://nrc-stp.ornl.gov/

Database of all reported NRC and AgreementDatabase of all reported NRC and Agreement State Events

Searchable: date, location, event type, isotope, model, manufacturer

Sealed Source & Device Workshop Lessons Learned: 8

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Points to Consider

People, procedures and equipment with respect to the use environment

Apply root cause(s) of past incidents of similar devices to current source/device design evaluation

Apply FMEA/hazard analysis to design and user instruction (minimize probability and consequences of failure modes)

Sealed Source & Device Workshop Lessons Learned: 9

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Selected Incidents

Brachytherapy Source Failure

- Source Design

- Device Design

- Failure to Survey

- Room Monitor

- Failure to Respond to Monitor

Radiography Cable Connector

- Design

- Quality Control

Sealed Source & Device Workshop Lessons Learned: 10

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Selected Incidents (cont.)

Moisture Density Gauge Source Rods

- Design

- Production

- Quality Control

- Use Conditions

Sealed Source & Device Workshop Lessons Learned: 11

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Selected Incidents

Industrial Gauge Shutter Failure

Excessive vibration (070178)Excessive vibration (070178)

Inadequate maintenance (050291)

Excessive heat (080149)

Sealed Source & Device Workshop Lessons Learned: 12

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Selected Incidents

Irradiators

Source rack stuck in exposed position (060588)

Intermittent malfunction – need positive position indicator and interlock (060289)

Sealed Source & Device Workshop Lessons Learned: 13

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Selected Incidents

Shielding Failures

Source cable cut (050569)

Source separate from gauge (060404)

Melt lead out of gauge (070475)

Sealed Source & Device Workshop Lessons Learned: 14

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Varian Varisource HDRSSD CA-0661-D-103-S

Overcranking pulls source out of safe

Four events from 2004-2007

Investigation coordinated between NRC andInvestigation coordinated between NRC and RHB

Varian HQ is in Virginia (NRC regulatory space)

M+D done from California (RHB reg space)

SSD held under CA

Sealed Source & Device Workshop Lessons Learned: 15

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Varisource OvercrankingInitial Part 21 determination

City of Hope Hospital incident in 2007

Two previous similar incidentsTwo previous similar incidents

CA, NRC, Varian agree that a root cause investigation is needed

Varian files preliminary report

Sealed Source & Device Workshop Lessons Learned: 16

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VarisourceIncident impacts

381 mrem total collective dose equivalent

186 units in USA have the potential for the same186 units in USA have the potential for the same problem

NRC and CA RHB time spent investigating Varian

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Varisource Root Cause

If you turn the emergency hand crank too far it protrudes from the shielded safe area.

More training needed

More labeling needed

More communication needed

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Varisource remedies

Issued a Customer technical bulletin

Develop and apply a better warning labelDevelop and apply a better warning label

Revise the user training to include a specific signoff on this issue

Revise user manual

Sealed Source & Device Workshop Lessons Learned: 22

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Mick Radio-Nuclear InstrumentsMick Applicator

Brachytherapy seed source ruptures

Occurred when the seed jammed in a MickOccurred when the seed jammed in a Mick Applicator

10 occurrences in 5 years

Contamination can be spread to surrounding surfaces

Sealed Source & Device Workshop Lessons Learned: 23

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Mick ApplicatorUse and Mechanical Description

An applicator for manual brachytherapy which is made up of the cartridge of seeds, a plunger and the holder that connects the cartridge to a

f fneedle for insertion of the seeds into the patient

When the plunger only can go down a small fraction of an inch then the user knows there is a problem

Sealed Source & Device Workshop Lessons Learned: 24

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Mick ApplicatorInvestigation Results

There is an association of seed jamming and failure to perform the recommended preventive maintenance

Seed cartridges just click in place, screwing them in screws them up

Disposable seed cartridges should be disposed of, not reused

Disposable seed cartridges hold 15 seeds, reusable ones only hold 10 seeds

Sealed Source & Device Workshop Lessons Learned: 25

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Mick ApplicatorRemedial Measures

All of these issues are training and labeling issues

An NRC Information Notice was issued

A State of Wisconsin Information Notice was issued

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NDT Repair Service and SupplyPart 21 Investigation

Two source disconnects were associated with equipment obtained from NDTRSS

NDT was notified by TEAM Industrial Service that a source disconnect occurred

NDTRSS conducted a root cause investigation

NDTRSS determined the root cause and recalled the entire lot

NDTRSS filed an equipment failure report with the NRC and had an announced inspection by the NRC to evaluate their response

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NDTRSS Part 21 InvestigationDescription

Drive cable was not connected to the source assembly during the connection of the control drive assembly to the exposure device

Radioactive source was pushed out of the exposure device with no means to retract it

A part of the control drive assembly adaptor did not meet the design specs but was used for distribution

Sealed Source & Device Workshop Lessons Learned: 28

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NDTRSS Part 21 InvestigationRemedial Actions

The entire lot of 25 devices was recalled (only 9 were defective)

Customers were notified in writing

A quality assurance step was added for after equipment modification within the NDTRSS procedures

A defect report was filed with the NRC

NRC staff evaluated the investigation

Sealed Source & Device Workshop Lessons Learned: 29