Inspection report: ANSTO OPAL Reactor, Lucas Heights, (R21/12455)

An inspection was conducted as part of ARPANSA’s baseline inspection program to assess compliance with the Australian Radiation Protection and Nuclear Safety Act 1998 (the Act), the Australian Radiation Protection and Nuclear Safety Regulations 2018 (the Regulations), and conditions of facility licence F0157. 

The scope of the inspection included an assessment of ANSTO OPAL Reactor’s performance against the Performance Objectives and Criteria (POC) in the area of radiation protection and cross cutters. The inspection consisted of a review of records, interviews, and physical inspection of the facility. 

Background

The OPAL facility is a 20 MW multipurpose research reactor that provides a variety of benefits to the community including production of radioisotopes for nuclear medicine and neutron scattering research. The main codes and standards applicable to this facility are those that appear in section 59 of the Regulations plus AS 2243.4:2018 Safety in laboratories ionizing radiation.  

Observations

Overall, the radiation protection was found to be appropriately managed at the OPAL facility. The dedicated ANSTO Radiation Protection Service (RPS) personnel provide professional support to OPAL personnel and management. The radiation protection management and practices including performance in three cross-cutting areas of safety culture, human performance and performance improvement were found to be sound.  One area for improvement was identified. 

Radiation protection

The only area for improvement identified in the previous ARPANSA inspection on radiation protection was an inconsistency of the Health Physics logbook records. During this inspection a sample of more than a month’s worth of logbook records was audited and no shortfall was identified. 

The safety management system is used for all aspects of radiation protection. The procedures and instructions are used for all work routine activities and the radiological risk assessment is an integral part of the process. The documents inspected were found to have been periodically reviewed and updated when needed. Safe Work Method and Environmental Statements (SWMES) that assess risks including radiological risks are developed for non-routine activities. It was demonstrated that the Radiation Protection Advisor (RPA) participates in developing of such assessments. A number of instructions and SWMES were inspected. No inconsistencies were identified.

ANSTO has developed and implemented an overarching set of radiation protection protocols that have been adopted by facilities including the OPAL reactor. These procedures are adapted to facilities such as the OPAL reactor to reflect specific hazards. Processes describing the movement of material, tools and equipment between areas with different radiation and contamination classifications were examined and no inconsistency were found.

ANSTO RPS provide health physics support and radiation protection advice to the OPAL reactor facility. A RPA and two health physics surveyors (HPS) are currently allocated to the facility for operational support. This support was shown to be adequately flexible to cover occasional work conducted outside of normal business hours. This level of support has been maintained even during the period of COVID-19 restrictions and found to be adequate. 

Periodic surveys are conducted for radiation and non-radiation areas to check the level of radiation and contamination. Many health physics survey records were examined to verify frequency and results. All records examined indicated that the surveys have been completed within the timeframes specified in the relevant procedures, and radiation levels and contamination were below the levels specified for the respective areas. No discrepancies were found.

Airborne and liquid discharges are reported to ARPANSA quarterly as required by licence conditions. No deviations were identified in the records. All discharges were well within the notification levels stipulated by licence conditions.

The ANSTO RPS participates in assessment of projects where radiation hazards are involved. A few such projects were examined with a focus on the involvement of radiation protection personnel such as the TG 123 project implemented recently. RPA involvement was found to be sufficient, and an adequate level of engagement has been demonstrated throughout the project from the beginning when the doses were estimated, through the dose monitoring activities during the project run to the post-implementation evaluation phase.

Multiple controls and defences are used to avoid unplanned radiological events. One of the most important controls are those that form the operating limits and conditions (OLC) relevant to radiation protection. These OLCs are generally associated with radiation monitoring devices continuously checking the OPAL reactor circuits, working environment, and discharges from the facility. The maintenance of all relevant systems was found to be in compliance with the relevant OLCs and associated surveillance requirements. 

Australian Standard AS 2243.4: 2018 Safety in laboratories ionizing radiation requires annual instrument calibration. A walk around of the facility confirmed that all but one of approximately 20 instruments inspected had been appropriately calibrated. The one hand-held contamination detector on L13 of building 80 was out of calibration by a week. In general, the instrument calibration is scheduled using the SAP system, which includes hand-held instruments. Calibration schedules of some instruments were reviewed during the inspection and no inconsistency was identified. Therefore, identifying one instrument outside the calibration period does not suggest a systemic problem.

Selected radiation events over the last two years were examined. ANSTO provided evidence of actions taken to maximise learning. The inspection verified action status and effectiveness of controls. For example, in October 2019, a HPS identified some contaminated items that were not labelled correctly in the rig maintenance room. The equipment in the room at that time was found to be not entirely in accordance with the relevant OPAL waste management procedure. During the current inspection walk around, improvements in management of the items temporarily stored in the room were observed. The equipment permanently located in the room was arranged according to the ‘five-S’ principle in the designated locations that were clearly marked. Tools used for contaminated items are now stored in the lockable red toolbox recently introduced to improve tool management. Although all contaminated items were wrapped in pink plastic to prevent spreading contamination, some of them did not carry current information of the level of contamination. However, it is recognised that OPAL has improved in this specific area and actions identified to further improve the management of equipment in the maintenance and utilisation rooms in building 80 are ongoing. Therefore, this shortfall is considered to be a work in progress.

Recent event GRC 11580 involved heavy water contamination of two personnel during a maintenance activity. Although the actual contamination and doses received by the affected people were minor, ANSTO conducted a thorough investigation to maximise learning. One of the recommended actions identified by the ANSTO independent investigator was to improve the already existing OPAL reactor specific training, particularly to enhance training on the facility radiological hazards. It is noted that the investigation of a contamination event in another ANSTO facility (which resulted in a major personal contamination) identified similar opportunities for improvement in the relatively recent past. Therefore, enhancing awareness of the OPAL reactor-specific radiological hazards by emphasising the maximum potential consequences for work activities and their potential health effects is presented here as an area for improvement. 

ANSTO provides quarterly reports to ARPANSA on radiation doses to personnel for the entire site. Doses over the past two quarters were found to be slightly elevated due to extensive maintenance being carried out during recent reactor shutdowns. However, the doses remained well within the annual dose limits which require the average dose over 5 years to be below 20 mSv and the dose in a single year to be below 50 mSv. 

The doses for each planned project task are estimated prior to commencement. Appropriate mitigating measures to minimise the doses are identified, reviewed and approved according to established ANSTO and OPAL specific protocols. The relevant documentation supporting a sample of projects was examined and no deviation from the approved methodology was identified. For example, actual doses received by personnel involved in project TG123 that included replacement of the beam primary shutters were found to be lower than previously estimated. This indicates that an appropriate conservatism was adopted.

ANSTO developed guide G-1372 in 2018 that assists in tailoring dose constraints to individual facilities. The OPAL reactor followed the guide in 2019 when the new dose constraint of 2 mSv was established for the facility.  

Findings

The licence holder was found to be in compliance with the requirements of the Act, the Regulations, and licence conditions. 

The inspection revealed the following area for improvement:

• OPAL radiation protection training could be improved by enhancing the emphasis on consequences and health effects associated with the existing specific radiological hazards.

It is expected that improvement actions will be taken in a timely manner.