GER Category 2 flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

GER Category 2 authorization

A national licensing tier for industrial radiography practices. The competent authority sets licence conditions, dose limits, notification thresholds and inspection rights; the licensee remains legally responsible for safety.

Graded approach

The principle in GSR Part 3 that authorization and control are proportionate to risk: notification for low-risk practices, registration or full licence for higher-risk ones such as industrial radiography.

Occupational dose limit

Under GSR Part 3, 20 mSv per year averaged over five years, with no more than 50 mSv in any single year. Apprentices aged 16 to 18 are limited to 6 mSv per year.

Public dose limit

1 mSv per year for members of the public from all authorized practices. The regulator sets a lower dose constraint for each individual practice to keep the total below the limit.

Licensee responsibility

The holder of the authorization is legally accountable for radiation safety. Duties may be assigned to an RPO and to qualified radiographers, but accountability cannot be transferred away from the licensee.

ALARA optimization

Keeping doses as low as reasonably achievable, economic and social factors considered. Implemented through dose constraints, investigation levels, distance, shielding, time control and periodic review of dose trends.

Inverse-square law

For a point source, dose rate is inversely proportional to the square of distance: doubling the distance reduces the dose rate to one quarter. Distance is the fastest control in an exposure emergency.

Half-value and tenth-value layers

HVL is the shield thickness that halves gamma intensity; TVL reduces it to one tenth. HVL equals ln2 divided by the linear attenuation coefficient, about 0.693 over mu.

Controlled area boundary

A physically demarcated area where occupational exposure is possible and access is restricted. Its boundary is set from measured dose rates, commonly where dose rate may exceed 7.5 microSv per hour.

Extremity dosimetry

Ring or wrist dosimeters worn in addition to the whole-body badge. Hand doses during source cranking and handling can exceed body dose, so extremity monitoring is required in gamma radiography.

Ir-192 source characteristics

Iridium-192 has a half-life of about 74 days and principal gamma energies around 0.3 to 0.6 MeV. Its relatively low energy means thinner shielding than Co-60 for the same activity.

Sealed source leak test

A wipe test of the source, its housing and the guide tube, performed at regulator-set intervals. A result above about 185 Bq (0.005 microCi) indicates leakage and requires source withdrawal.

Gamma exposure device

A shielded container holding a sealed source that is driven out through a guide tube to a collimator by crank or pneumatics, then returned to the shielded position after each exposure.

IAEA source categorization

A five-tier hazard scale for sealed sources. Category 1 is the most dangerous, potentially fatal if uncontrolled; industrial radiography sources are typically Category 2, still high risk and tightly secured.

Source decay calculation

Current activity equals initial activity multiplied by exp(-ln2 times elapsed time divided by half-life). Exposure charts must be recalculated as the source decays to keep film density correct.

Pre-use equipment check

Verification before each shift of survey meter function and battery, source position indicator, locks and keys, warning signals, guide tube condition and collimator attachment. Defects remove equipment from service.

Controlled area establishment

Before exposure, survey the dose rate and cordon the area at a measured boundary, post warning signs, use a physical barrier, and confirm no person remains inside the area.

Stuck source response

Stop work, evacuate and cordon using measured dose rates, notify the RPO and regulator, and recover only with a survey meter, long-handled tools and shielding, by trained personnel.

Exposure time calculation

Exposure time equals the required film dose divided by the dose rate at the film. Dose rate comes from source activity, distance and shielding, and is verified with a calibrated survey meter.

Collimator function

A device that restricts the beam to the area of interest, reducing scatter and the surrounding radiation field. It is not a substitute for distance, barriers and area control.

Post-exposure verification

Confirm with a survey meter that the source is fully shielded, lock the device, remove the key, and record the exposure, survey results and any anomaly in the log.

Emergency plan scenarios

Documented responses for lost or stolen source, stuck or disconnected source, fire or flood in the store, transport accident, and personal overexposure, each with actions, roles and contact numbers.

Lost source notification

Notify the regulator and police immediately, activate the security plan, and circulate the radionuclide, activity, serial number and physical description to support search and recovery.

Overexposure dose reconstruction

After a suspected overexposure, remove the person from the field, obtain medical assessment, reconstruct dose from dosimeters and biological dosimetry if indicated, and report to the regulator.

Emergency drill requirement

Exercises at intervals defined in the plan, commonly at least annually and after significant changes in equipment or personnel. Drills are recorded and lessons learned update the plan.

Emergency recovery closure

Recovery ends when the source is verified shielded or in safe storage, the area is surveyed and released, and a written report with doses and corrective actions is issued.

SSR-6 package types

The IAEA transport regulations classify packages as excepted, industrial, Type A, Type B or Type C according to activity and hazard, with Type B retaining containment under accident conditions.

Transport index

The maximum dose rate at one metre from the package surface, expressed in mSv per hour multiplied by 100. It sets the label category and controls segregation and stacking in transport.

Yellow-III label criteria

A package labelled III-Yellow has a surface dose rate up to 2 mSv per hour and a transport index up to 10. Higher values require exclusive-use shipment conditions and special controls.

Source store requirements

A dedicated, locked, shielded store with access control, a serial-number inventory, and boundary dose-rate monitoring so that public dose limits are met outside the store.

Calibration traceability

Survey meters and dosimeters are calibrated against a national standard at regulator-set intervals, commonly annually and after repair, with certificates stating reference radiation and uncertainty.

Corrective action process

Any deviation such as a stuck source, failed leak test or missing dosimeter is recorded, investigated for root cause, corrected, and verified for effectiveness, with the record retained.