Nuclear Safety and Security Commission

NSSC Held the 147th Meeting of the Commission

■ The ｢ bill to impose an administrative action on a radiation user ｣ was deliberated and passed.

■ The 「 bill to modify the construction permit and operating license of nuclear facilities 」 for the Hanul

Units 1 and 2 and the Shinkori Units 5 and 6 was deliberated and passed.

On 10 September, the Nuclear Safety and Security Commission (Uhm Jaesik, hereinafter referred to as the

“NSSC”) held the 147th meeting of the Commission where the commissioners deliberated and passed two bills.

※ In order to prevent the spread of COVID 19, commissioners’ meetings have been held in the form of a meeting with limited

face to face interactions since 10 April by minimizing the number of attendees, checking body temperatures, wearing masks and

physically distancing from each other.

As one radiation user violated the safety management regulations that mu

st be observed in a radiographic testing site (Article 59 Paragraph 3 of the 「 Nuclear Safety Act 」 ), the commissioners deliberated and passed

the ｢ bill to impose an administrative action ｣ that would impose a fine of 240 million KRW In addition, the commissioners deliberated and passed the ｢ bill to modify the construction permit and operating license of nuclear facilities. ｣ 

The modification of the operating license for the Hanul Units 1 and 2 is about ➊ improving existing or installing new zinc injection facilities for reactor coolant system. The modification of the construction permit for the Shinkori Units 5 and 6 is about ➋ reflecting detailed designs of the air

conditioning system i n the nuclear fuel handling zone in the drawings as their designs have been finalized.

In addition, the Korea Institute of Nuclear Safety (President Son Jaeyoung, hereinafter referred to as KINS)

reported to the commissioners the results of the review on document conformity for the application for

approval for decommissioning of the Kori Unit 1*, submitted by the KHNP (on 14 May, 2021) and the licensing plan.

＊ (Application Documents) Final decomissioning plan, quality assurance plan for decomissioning, documents on opinions on the

draft decom i ssioning plan, results of public hearings

The civil investigation team and the Current Issue Communication Council is preparing for the announcement of the progress of the investigation and future plans.

On 7 September, JTBC news reported under the headline, “Radioactive materials leaked from the Wolsong Unit 1.. the 1st investigation report obtained.” In this news story, JTBC argued that it obtained the 1st investigation report of the civil investigation team which reveals radioactive materials were detected in the water and soil within the Wolsong Unit 1. It also argued that the report pointed out the problem of the nuclear spent fuel storage facility, and judged that radioactive materials had been continuously leaked for about 20 years.

Regarding this media report, the civil investigation team and the Current Issue Communication Council has the position as below:

The civil investigation team for tritium in the Wolsong Nuclear Power Plant is collecting opinions from the Current Issue Communication Council after summarizing the progress of the first investigation that spans from the launch on March 30, this year to now, and future plans.

The report that the media introduced in the news is a draft version for review. When the final draft is prepared through a joint meeting between the civil investigative team and the Current Issue Communication Council scheduled for 9 September, press releases will be distributed.

NSSC Held the 146th Meeting of the Commission

■ The ｢ bill to modify the construction permit, operating and business licenses of nuclear facilities ｣ was

deliberated and passed for the Shinkori Units 3 to 6 and KEPCO Nuclear Fuel Plant 3.

The Nuclear Safety and Security Commission (Chairman Jaesik Um, hereinafter referred to as the NSSC)

held the 146th meeting of the Commission on Friday, August 27, 2021, and deliberated and decided to pass

the bill to modify the license of nuclear facilities. Modifications are as follows.

① First, improving the nuclear power plant control method and system so that the reactor does not trip even

when a 12 finger single control element assembly of the Shinkori Units 3 and 4 drops.

② Second, reflecting the detailed designs of the Containment Spray System of the Shinkori Units 5 and 6 i n

the text and drawings as the designs have been finalized.

③ Lastly, reflecting the detailed designs of the electrical facilities and fire protection facilities of the

KEPCO Nuclear Fuel Plant 3, which is under construction, in the license documents as the designs have

been finalized

The NSSC Checked Preparedness Against Typhoon and Started to Work on Emergency Duty

The NSSC held an emergency meeting to check the preparedness against the twelfth typhoon “Omais.”

On 23 August , the Nuclear Safety and Security Commission (Chairperson,

UhmJaesik, hereinafter referred to as the “NSSC”) held an emergency meeting

presided over b y Chairperson, regarding the twelfth typhoon “Omais” ascending

north, to check preparedness of nuclear facilities*.

* Nuclear power plants, low and med level radioactive waste disposal facilities, research reactors, etc.

The meeting was held in the emergency room of the NSSC with 5 site offices located

in the sites (Kori, Hanbit, Hanul, Wolsong and Daejeon), the Technical Support

Organizations (the Korea Institute of Nuclear Safety and the Korea Institute of Non

proliferation and Control), the Korea Hydro and Nuclear Power (KHNP), and other

stakeholders in the form of video conference.

The NSSC was briefed on the results* of the summer’s special inspection conducted

from 28 June to 2 July and the preparedness of the facilities against the twelfth

typhoon “Omais” t hat is ascending north.

* Results were good overall, but improvement is being pursued for some deficiencies such as poor

fixing of the conduit in the intake port and drainage management in the drain port.

Chairperson Uhm Jaesik said in the meeting, “As heavy rainfalls are expected in and

around the southern part of the Korean peninsula due to the typhoon and the

atmospheric depression coming from the West Sea is likely to be accompanied by

lightning and thunder, we need to check the safety of the sites more thoroughly.” He

also encouraged the staff to work on emergency duty until the meteorological

warning gets lifted and report promptly when an abnormal event occurs.

NSSC Approved Restart of Hanaro Reactor

The Nuclear Safety and Security Commission (Chairperson Uhm Jaesik, hereinafter referred to as the NSSC) completed the investigation of the Hanaro research reactor at the Korea Atomic Energy Research Institute that had been automatically shut down on 1 July, confirmed the safety of the reactor, and thereby approved the restart of the reactor on 23 August.

This event took place as an abnormal condition occurred in the hydrogen control system of the cold neutron experimental facility and the Hanaro reactor was automatically shut down to protect the laboratories

According to the investigation result, the cause of the failure in the hydrogen control system is that the fuse of the pressure gauge circuit of the hydrogen control system that cools neutrons was blown, causing an error in the hydrogen pressure measurement (hydrogen pressure signal “0” was generated).

As a result of this error, the control valve for hydrogen supply was opened and high pressure of hydrogen (hydrogen pressure exceeding 200 kPa) was generated. Finally, the shutdown signal for the Hanaro reactor was generated to protect the cold neutral experimental facility.

It was found that the cause of the blown fuse is that it had been used without replacement for a long period (13 years) leading to the disconnection of the weld due to aging.

After this event, the Korea Atomic Energy Research Institute decided to replace all fuses (112 pieces) in the control computer of the cold neutron experimental facility and the reactor control/protection system, and prepared a management procedure to replace fuses every 3 years.

In the future, the NSSC plans to continuously monitor the implementation of the Korea Atomic Energy Research Institute's plans to prevent recurrence.

Magnitude 4.0 Earthquake Struck Sea 124km Southwest from

Eocheong Island, Gunsansi, Jeollabuk do; NPP Operation Not Affected

Regarding the magnitude 4.0 earthquake that occurred at around

9:40 am today in the sea (7 km deep) 1 24 km southwest from Eocheong island , Gunsan si, Jeollabuk

do. The Nuclear Safety and Security Commission (Chairperson Uhm Jae sik,

hereinafter referred to as the “NSSC”) confirmed that there is no abnormality in the

safety of nuclear power plants (including low to mid level radioactive waste disposal

facilities and research reactors).

At the Hanbit Nuclear Power Plant which is located closest to the epicenter (about

1 58.5km away from the location), alarm was not set off because the measurements of

seismic levels w ere less than the value set for earthquake warning (0.01 g). At the

other nuclear power plants, the measured values were also below the value set for

earthquake warning .

As a result of the emergency onsite safety inspection so far, it has been confirmed

that there are neither any special issues in the safety variables of nuclear facilities nor

nuclear power plants with reduced power or manually shutdown due to the impact of

this earthquake.

※ the value to set off earthquake warning at nuc lear power plants (0.01 g), value set f or manual

shutdown (0.1 g), value set for automatic shutdown (0.18 g), design standard for nuclear power plants

(0.2 or 0.3)

In preparation for aftershocks afterwards, the NSSC plans to continuously check

safety, such as checking whether or not safety inspections are performed by the

nuclear licensee s, including the Korea Hydro and Nuclear Power, and inspection

results.