NSSC: "Radioactive Material Released from Radioactive Waste Treatment Auxiliary Facility at Korea Atomic Energy Research Institute... Under Investigation"

[Asia Economy Reporter Moon Chaeseok] The Nuclear Safety and Security Commission announced on the 22nd that it is investigating after receiving a report on the 21st that artificial radioactive nuclides were released into nearby stormwater drains from some facilities within the Korea Atomic Energy Research Institute (KAERI) located in Deokjin-dong, Yuseong-gu, Daejeon.

The commission stated that it received a report from KAERI indicating that cesium-137, cesium-134, cobalt-60, and other radionuclides flowed into the stormwater drainage area around the facility from a natural evaporation facility within KAERI.

This facility is an auxiliary facility of a test facility and radioactive waste treatment facility. It naturally evaporates moisture from very low-level liquid radioactive waste using solar heat.

According to the report, soil samples were collected from riverbeds near the KAERI main gate on the 30th of last year, and on the 6th of this year, radioactivity concentration analysis showed a temporary increase.

At the drainage point in front of the main gate within the KAERI site, the radioactivity concentration of cesium-137 was temporarily elevated to 25.5 Bq/kg, compared to the average value of <0.432 Bq/kg over the past three years.

According to KAERI's own investigation so far, the highest radioactivity concentration of cesium-137 measured in riverbed soil within KAERI was 138 Bq/kg.

Downstream external riverbed soil showed concentrations ranging from 3.1 to 12.4 Bq/kg, which falls within the range of 0.555 to 17.9 Bq/kg measured directly by KAERI around the facility during 2018. No radioactivity was detected in the river water.

Accordingly, on the 21st, KAERI traced the point where cesium-137 temporarily increased and investigated the connected stormwater drains within the institute, discovering that the radiation dose rate inside a manhole in front of the natural evaporation facility reached up to 3.4 μSv/h. This suggests that the natural evaporation facility is presumed to be the cause.

The Korea Institute of Nuclear Safety (KINS) investigation team dispatched by the commission instructed KAERI to collect samples and remove contaminated soil to analyze radiation levels in the manhole area. They also sealed the area to prevent rainwater inflow.

Currently, the KINS investigation team is measuring radioactive material concentrations at various locations in the surrounding riverbed soil, conducting environmental impact assessments, and inspecting all facilities.

The commission stated that it plans to transparently disclose the results after reviewing the investigation team's findings.