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Prachinburi Court has ordered immediate imprisonment without suspension and imposed heavy fines on company directors in a case involving the loss of cesium-137, citing safety negligence and delayed incident reporting that led to the radioactive material being melted down.
On 15 Jan 2026, reporters reported that on 24 Dec 2025, Prachinburi Provincial Court read its judgment in criminal case no. A475/2568, in which the Prachinburi Provincial Public Prosecutor was the plaintiff and National Power Plant 5 Co., Ltd. was defendant 1, Mr. Prayad Chaemphucha defendant 2, Mr. Thanongsak Srisongmuang defendant 3, and Mr. Singh Niammunee defendant 4. The case involved the loss of radioactive cesium-137 material. The prosecution sought penalties under the Peaceful Nuclear Energy Act 2016, sections 4, 5, 8, 28, 30, 91, 100, 107, 110, 122, 126, and 143, as well as Criminal Code sections 33, 83, and 91, and requested confiscation of all evidence to be handed over to the Office of Atoms for Peace for destruction or appropriate handling. The prosecution also requested that the defendants be jointly responsible for the costs incurred for disposal. All four defendants pleaded not guilty.
The court summarized that defendant company 1 and defendant 2, as CEO, were guilty of neglecting safety measures by failing to secure the installed material properly, resulting in loss. They also allowed the CCTV system to be faulty, preventing incident investigation. Furthermore, they were guilty of delaying notification to the Office of Atoms for Peace by three days, whereas the law requires immediate reporting of hazardous events. This delay caused the material to be sold and melted down, contaminating over 30 tons of iron dust and the environment.
The court fined defendant company 1 a total of 200,000 baht and sentenced defendant 2 to four months in prison. Defendant 4, as head of the legal department who was aware of the incident but failed to notify authorities as required, was sentenced to six months in prison without suspension. The court found that defendants 2 and 4 showed no remorse or responsibility toward public safety or affected parties; therefore, there was no reason to suspend imprisonment.
Meanwhile, defendant 3 was acquitted due to lack of evidence linking him to the case.
The court ordered all confiscated materials to be destroyed by the Office of Atoms for Peace, with defendant company 1 responsible for all associated costs.
Subsequently, defendants 2 and 4 filed bail requests during their appeals, and Prachinburi Provincial Court approved their temporary release upon posting bail of 130,000 baht each.