Press Release
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- [April 25, 2024] NSSC Held 193rd Meeting of Commission
NSSC Held 193rd Meeting of Commission
The 193rd meeting of the Commission was convened
The Nuclear Safety and Security Commission (Chairperson Yoo Guk-hee, hereinafter referred to as the “NSSC”) held the 193rd meeting of the Commission on April 25th, 2024 (Thurs), where the commissioners deliberated and resolved one agenda item.
(DeliberationㆍResolution item 1) The commissioners approved the bill on 「 Modification of the Operating License on Nuclear Power Facilities (draft)」 to revise methods and materials to maintain the partial nozzles of the lower reactor head penetrations of Hanbit Units 1 and 2.
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- [April 24, 2024] The NSSC Launched Inspection on Automatic Activation of Emergency Diesel Generator of Hanbit Unit 4
The NSSC Launched Inspection on Automatic Activation of Emergency Diesel Generator of Hanbit Unit 4
The NSSC began investigating the automatic activation of the emergency diesel generator of Hanbit Unit 4.
The Nuclear Safety and Security Commission (Chairperson Yoo Guk-hee, hereinafter referred to as the “NSSC”) was notified by the KHNP that one of the two emergency diesel generators of Hanbit Unit 4 (one is currently under maintenance) was automatically activated at 8:27 pm on April 23rd (Tue).
Hanbit Unit 4 is tripped as the Unit is under planned overhaul (started on April 21st), and it was confirmed that there is no irregularity such as radiation exposure.
Currently, the NSSC is figuring out the safety through the site office established at the NPP site and will dispatch the investigation team composed of experts from the Korea Institute of Nuclear Safety.
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- [April 23, 2024] Endeavor to Provide a Safe Environment For Radiographic Test At Shipbuilding‧Offshore Plant Sites
Endeavor to Provide a Safe Environment For Radiographic Test At Shipbuilding Offshore Plant Sites
The NSSC endeavors to make radiographic tests safe at shipbuilding offshore plant sites.
- Launch a meeting with contractors who request radiographic tests at Samsung Heavy Industries -
Chairperson Yoo Guk-hee from the Nuclear Safety and Security Commission (hereinafter ‘NSSC’) held a meeting with contractors of radiographic tests for the shipbuilding·offshore plant at Samsung Heavy Industries (located at Geoje-si, Gyeongnam) and monitored the working sites.
* 5 contractors of radiographic test in shipbuilding offshore plants, including Samsung Heavy Industries Co., Ltd., and Hanwha Ocean.
This meeting was a part of the ‘round-table meeting for nuclear safety*.’ It was the second meeting, and the previous meeting was held last year at Ulsan for large-scale key infrastructures related to shipbuilding‧offshore plants.
* The NSSC promoted a round-table meeting for nuclear safety starting in 2023 on a regular basis to secure people’s trust, understanding, and support by encouraging communication between fields.
The radiographic test checks welded defects that cannot be found with bare eyes during shipbuilding. It is often used in large-scale basic industries like shipbuilding·offshore plants for quality control.
However, radiographic tests from the radiation industry have a relatively high exposure dose and are more likely to lead to accidents, requiring exceptional safety management. Therefore, the NSSC makes contractors responsible for safety measures such as providing a safe working environment by being equipped with radiation shield facilities and reporting daily working progress.
In this meeting, the NSSC asked contractors to be more active in the safety of radiographic tests and to devote themselves to the provision of contractors’ safety management responsibility as defined in the Nuclear Safety Act.
Moreover, the NSSC listened to contractors and radiation safety managers who took charge of radiographic tests on their difficulties and improvements while working on site, committing to revise irrational regulations while keeping workers safe.
After the meeting, the NSSC checked the site of the radiographic test in Samsung Heavy Industries to see if the test proceeded safely within the contractor-provided working environment.
Chairperson Yoo said, “A great deal of effort is needed from contractors to keep radiographic tests safe. I would like to request contractors to provide a safe working environment to minimize the radiation exposure on their workers.”
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- [April 17, 2024] NSSC Approved Criticality of Shinhanul Unit 1 During Periodic Inspection
NSSC Approved Criticality of Shinhanul Unit 1 During Periodic Inspection
The NSSC allowed the criticality of Shinhanul Unit 1 during the periodic inspection
- Satisfied the technical standards on major tests such as the integrated leakage rate test of
containment building
- Finally , the safety was confirmed through follow up tests such as a power uprate test.
On April 17th , the Nuclear Safety and Security Commission (Chairperson Yoo Guk hee, in short NSSC hereafter) allowed the criticality* of the Shinhanul Unit 1 which had been undergoing a periodic inspection since January 5th, 2024.
* Criticality means making nuclear fissions in the reactor occur continuously, resulting in a state where the generated neutrons are equal to the extinct neutrons . Therefore, the number of neutrons is in equilibrium.
The NSSC checked the result of 86 out of 97 test items to be carried out before the reactor reached its criticality. Then, it confirmed that it can safely reach the criticality.
The NSSC identified the cause* of why the reactor automatically tripped on January 2nd, 2024, and reviewed whether the preventive measures against reoccurrence** were appropriate during the periodic inspection.
* A maintenance man accidentally operated an output interrupter, mistaking it for a status light, while the output interrupter's circuit produce d current to exciters was installed . It led turbines/ generators to stop their operation, and the accumulated xenon caused the reactor to shut .
** The Korea Hydro and Nuclear Power Co., Ltd. (KHNP) introduced preventive measures against against reoccurrence such as maintaining the circuit of output interrupter, improving equipment to prevent human errors, and others.
Major tests confirmed that the result satisfied the related technical standards. The tests include the integrated leakage rate test of containment building s and checks on fire protection and the conditions of safety related equipment and pumps.
The NSSC will allow the criticality of Shinhanul Unit 1 based on the results of the periodic inspection and finally confirm its safety through follow up tests (11 tests) such as a power uprate test.
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- [April 15, 2024] NSSC Approved Resumption of Hanul Unit 6
NSSC Approved Resumption of Hanul Unit 6
The Nuclear Safety and Security Commission (Chairperson Yoo Guk-hee, hereinafter referred to as the ‘NSSC’) completed the inspection of Hanul Unit 6 and allowed its resumption on April 15th. Hanul Unit 6 was automatically tripped on April 1st due to the low water level of the steam generators.
The inspection confirmed that it was due to the damage to signal lines that control the rotational speed of main feed water pumps in steam generators, resulting in reduced flow to steam generators.
The Korea Hydro and Nuclear Power Co., Ltd. (KHNP) completed fixing the signal lines and came up with preventive measures such as multiplexing the speed control of main feed water pumps.
The NSSC reviewed how appropriate the KHNP’s maintenance and preventive measures are and will further confirm the safety through a power ascension test and other methods.
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- [April 3, 2024] NSSC Checked on Safety Accident Readiness of Nuclear Facilities
NSSC Checked on Safety Accident Readiness of Nuclear Facilities
The NSSC checked the preparedness against safety accidents in nuclear facilities.
- Held a meeting to monitor issues related to safety, asking for the prevention of safety accidents such as fires that break out during spring seasons -
On the 3rd, chairperson Yoo Guk-hee from the Nuclear Safety and Security (‘NSSC’ in short hereafter) launched a meeting to check safety issues such as fires in nuclear facilities.
The meeting was online, and 5 site offices (Kori, Wolsong, Hanbit, Hanul, and Daejeon), the Korea Institute of Nuclear Safety (KINS), and the Korea Hydro and Nuclear Power Co., Ltd. (KHNP) participated. The fire safety results of nuclear facilities, preparedness, and prevention against safety accidents were shared at the meeting.
At the meeting, chairperson Yoo Guk-hee said, “Please carefully monitor and prepare for fires since they can affect the multiple systems of facilities. Institutes should check the sites cautiously.”
- Message from the Chairperson
- Chairperson Yoo Guk-hee
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