Reduce Dose and Increase Efficiency Using Unmanned Ground Systems for Radiation Protection Tasks - MTA-RP-005
| Administrative Items | |
|---|---|
| Date | 9/30/23 |
| Functional Area Where Benefits Will Be Realized | Radiation Protection
Chemistry and Environmental Maintenance |
| Reference Implementation Guidance |
Unmanned Ground System (UGS) Users’ Guide for Nuclear Power Plants (EPRI 3002025464) Cyber Security Technical Assessment Methodology (TAM) - Risk Informed Exploit Sequence Identification and Mitigation: Revision 2 (EPRI 3002012752) Guidelines for Electromagnetic Compatibility Testing of Power Plant Equipment: Revision 5 to TR-102323 (EPRI 3002015757) Reassessment of NRC’s Dollar Per Person‑Rem Conversion Factor Policy, Revision 1 (NUREG‑1530, Revision 1) |
| Industry SME | EPRI – PRR, Chemistry and Radiation Safety
Contact: nuclearplantmod@epri.com |
| Previous Implementation | This improvement has been implemented at several nuclear power plants. Please contact the EPRI SME for additional information. |
| Implementation Enablers | UGS implementation may require a wireless communication network for remote control and data collection/storage. Common enabling infrastructure includes site Wi‑Fi, mesh radio networks, or cellular/LTE networks. The following MTAs can be referenced for wireless network implementation guidance:
|
| Applicability | All reactor types
All geographic regions |
| Keywords | Ground robotics; Unmanned ground systems; UGS; radiation protection; RP; survey; mapping; source term |
| Business Case Analysis Cross-Reference | N/A |
Description
The Radiation Protection (RP) department performs activities such as source term characterization, dose mapping, hot‑spot identification, regular rounds, and pre‑job surveys to characterize radiation levels and sources daily throughout a nuclear plant. RP also supports inspections and manipulations in site Locked High Radiation Areas (LHRAs) and High Radiation Areas (HRAs). Traditionally, RP activities are manually carried out by a Radiation Protection Technician (RPT). Unmanned Ground Systems (UGS) can be leveraged to perform RP tasks remotely.
UGS are mobile robotic technologies that operate without onboard human presence. UGS can be controlled manually with input from an operator or utilize autonomous capabilities to perform missions such as daily RP rounds without operator input. UGS consist of a mobile platform, control system, and payloads. UGS equipped with dose‑rate meters or spectroscopy equipment payloads can be used as a remote alternative to manual data collection for various RP tasks. The remote technologies can alert the RP department if additional manual surveys are necessary based on collected data. UGS equipped with an arm attachment can interact with the surrounding environment to perform manipulations, retrieve items, hold RP instrumentation, and perform removable contamination surveys.
Implementing UGS for RP tasks as an alternative to manual execution reduces dose to site personnel; this is particularly beneficial in LHRAs/HRAs or in emergent scenarios where the radiological condition of an area is not well understood. Using UGS in emergent scenarios can also help prevent unnecessary outages and reactor down‑powers that may be required for personnel entries to LHRAs and HRAs. Leveraging UGS can also reduce overall labor hours associated with RP tasks and improve collected data quality.
Benefits
Benefits Estimate
Level 1 – Savings are expected to be less than $1 million per year per unit. Estimated savings are based on increased efficiencies for plant staff, dose savings and avoidance of reactor power reductions or reactor shutdown. Savings will depend on technology utilization and site‑specific realization of soft benefits, such as improved inspection quality and dose savings, and utilization of the UGS to avoid a reactor shutdown or down‑power. The US NRC provides guidance on quantification of dose savings in NUREG‑1530 Revision 1, which describes the dollar value of dose savings at $5,200 per person‑rem; informal benchmarking for the value of dose savings is between $25,000 to $80,000 per person‑rem.
Benefits Description
- Reduced dose to staff by saving time spent in radiologically hazardous areas. Sites that have implemented UGS report dose savings of up to 10 person-rem/year for a total estimated soft savings of up to $250,000 per year.
- Reduce time and lost-generation cost by preventing unnecessary outages and reactor downpowers during emergent scenarios. The savings associated with this are variable based upon seasonal power costs, but sites have reported savings between $60,000 to $600,000 based on avoidance of a reactor shutdown or downpower.
- Improved task performance by increasing the consistency and standardization of routine RP tasks and providing higher quantity and quality of data.
- Increased efficiencies by decreasing labor hours associated with RP tasks and allowing personnel to shift their attention towards other tasks.
Costs and Schedule
Cost
Level 3 – Implementation cost is expected to be less than $1 million. Estimated costs are on the order of $150,000‑$350,000 per UGS unit and depend on the robotic model, complexity, and desired payloads. Costs include procuring and integrating the UGS and associated infrastructure, including its payloads, docking stations, spare batteries, and UGS accessories. Additional costs specific to RP applications may be associated with UGS operator training, procedure changes, custom software integration, and the purchase of specialized end effectors and additional radiation detector instrumentation.
Schedule
Less than six months. Most UGS infrastructure (e.g., docking stations, fiducial markers) can be installed online, except for areas of high dose which may require installation while the plant is in an outage. The schedule also includes supplier‑based integration. Custom software integration or expansion of the site’s network capabilities to support UGS implementation may extend the schedule.
Scope Context
Cost and savings are based on a single unit.
Risks
- UGS integration to a plant’s network may present cybersecurity risks. Existing utility practices for satisfying US NRC cybersecurity requirements should be applied to help mitigate such risks. The EPRI Technical Assessment Methodology for UGS (EPRI 3002012752) may also be leveraged for guidance on identifying cybersecurity vulnerabilities and associated mitigations and controls.
- Electromagnetic Compatibility (EMC) must be considered to prevent electromagnetic interactions between the UGS and other systems. Following U.S. NRC EMC guidance for equipment EMC qualification and maintaining appropriate standoff distance to sensitive systems will mitigate such risks. EPRI Report 3002015757 provides additional guidance on EMC qualification and includes best practices for in‑plant EMC.
- Personnel and equipment safety concerns must be addressed to prevent personnel injury and damage to site assets. UGS models with obstacle detection and avoidance features, proper UGS implementation planning, personnel training, and forbidden zones around vulnerable equipment will mitigate such risks.
- A broken or lost UGS or UGS sub‑component can become a foreign material exclusion (FME) hazard. UGS operators can perform pre‑ and post‑mission inspections to ensure all sub‑components and payloads are accounted for and to provide confidence that foreign objects were not introduced during the mission. If a UGS becomes broken or lost in a high‑radiation area, a reactor down‑power may be required for retrieval. Using a tethered UGS for missions in sensitive locations can help reduce FME risk. The site should have a clear plan developed and communicated in the case of UGS‑related foreign material introduction.
- The site should also consider contamination risk if the UGS will be utilized in contaminated areas. UGS model can influence contamination risk (e.g., exterior material selection, IP rating, locomotion form) and protective coverings can be used to lower contamination risk. If contamination occurs, the site can leverage existing tool contamination protocols, such as performing equipment decontamination or the use of a hot tool crib.
- The site should maintain frequent communication with the regulator to ensure alignment and acceptance of UGS‑collected RP data.
- The physical layout of the RCA may limit the number of areas that can be accessed by the UGS for autonomous rounds, radiation surveys, and inspections due to locked doorways, difficult‑to‑operate doors, room configurations, and a lack of stairs. The site will need to account for this and provide operator assistance to perform these tasks.
SWEEP Score
| Category | Level | Description |
|---|---|---|
| Cost | 3 | Implementation cost is less than $1 million. Estimated cost is on the order of $50,000‑$300,000 for a single unit. |
| Savings | 1 | Savings are less than $1 million per year per unit. |
| Payback | 2 | Payback period is expected to be greater than one year but less than five years (inclusive). |
| Technical Readiness | 3 | The technology is ready for wide operational deployment. This technology has already been implemented at nuclear power plants. |
| Licensing Readiness | 3 | No changes are required for implementation. |
| Implementation Proficiency | 3 | The technology can be implemented by all sites, regardless of digital experience. |