How Singapore’s ‘radiation detectives’ ensure safety as South-east Asia explores nuclear energy
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Senior scientific officer Eugenia Wong conducting solid-phase extraction to isolates some radioactive substances at the National Radiochemistry Laboratory under NEA.
ST PHOTO: KEVIN LIM
- Singapore's National Radiochemistry Lab undergoes annual IAEA tests, assessing its ability to detect trace radiation, crucial as ASEAN considers nuclear power.
- The lab uses specialised equipment to analyse samples, including gamma ray spectrometers; Singapore actively participates in IAEA emergency drills.
- NEA monitors radiation levels islandwide and contributes to ASEAN's early warning network, while building capabilities for nuclear safety assessments.
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SINGAPORE – A tub of soil, a container full of crushed vegetation and a bottle of clear liquid were part of a package of items sent by the UN atomic watchdog to Singapore in 2025.
These items had arrived in Singapore in July 2025 as part of an annual test conducted by the Vienna-based International Atomic Energy Agency (IAEA), to assess national labs’ abilities to detect even trace amounts of radiation and measure the radioactivity of various particles.
Singapore has been participating in these exercises since 2018. But with ambitions to tap nuclear energy
Some items sent by the IAEA over the years, including a tub of crushed vegetation.
ST PHOTO: KEVIN LIM
On Jan 27, the media got a rare glimpse into the National Radiochemistry Laboratory, where such radioactivity monitoring tests are carried out. The lab under the National Environment Agency (NEA) is located within the Singapore Nuclear Research and Safety Institute
The items sent by the IAEA are usually spiked with very low and safe levels of radioactive substances, which do not pose a danger to the scientists.
Low, harmless levels of radiation are naturally present in the environment, soil and air, and even emitted by people.
There are three main types of radiation that the NEA’s tests work on: alpha and beta particles, and gamma rays.
Gamma rays can penetrate the human body and damage DNA, among other things. Alpha and beta particles are not as penetrating, but they pose a greater health risk and damage internal tissues when radioactive materials are inhaled, ingested or passed through wounds.
The proficiency test requires labs to analyse the samples typically within seven days for rapid reporting, and to ensure the scientists are able to deliver accurate results during crises.
Mr Ang Kok Kiat, group director of the NEA’s radiation protection and nuclear science group, which the lab falls under, said Singapore has aced the IAEA’s tests every year.
“We have performed pretty well in these (tests)... comparable to countries with established labs for a long time. When we see those results, we are among the top,” he added.
In 2025, the Singapore lab reported results for alpha-emitting substances using a new technique for the first time.
While the lab’s measurement of the substances was accurate, the IAEA provided some feedback for refinement, said NEA, such as increasing the sample amount for analyses.
“This feedback reflects the robustness of the testing process and supports the laboratory’s ongoing efforts to continuously enhance its performance,” added NEA.
Ensuring radiological safety
Singapore’s efforts to monitor background radioactivity levels are crucial for the country to know its baseline levels of radiation in the environment before nuclear plants emerge in the region, said Mr Ang.
Five ASEAN countries – Vietnam, Indonesia, the Philippines, Malaysia and Thailand – have said they are either studying the feasibility of advanced nuclear technology to meet their growing energy needs, or already have plans to build reactors in the coming decades.
Singapore, too, is mulling over the use of small modular nuclear reactors to meet its energy needs.
Singapore also actively participates in emergency drills run by the nuclear watchdog every year.
In one such scenario, the IAEA sends an alert to member countries of a fictional nuclear accident. Designated officials are required to acknowledge the message within 30 minutes.
The Republic strives to respond within 10 minutes, said Mr Ang.
Over two days in June 2025, Singapore joined more than 70 countries in a large-scale drill that simulated a severe accident at Romania’s nuclear plant.
Countries were tested on swift decision-making, public communication, and how they would conduct evacuations and distribute protective iodine tablets. These tablets protect the thyroid gland from radioactive iodine.
Other than participating in tests and exercises conducted by the IAEA, NEA also runs a network of around 40 monitoring stations islandwide, which includes nine stations located on reservoirs and coastal waters.
The agency’s National Radiochemistry Lab’s routine work includes testing soil and water samples islandwide at least twice a year, mainly to look out for elevated levels of manmade sources of radiation such as caesium-137 and cobalt-60 – substances that can be released during nuclear plant incidents.
So far, the lab has not detected any elevated levels of manmade radioactive substances, said Mr Loo Howe Kiat, deputy director of NEA’s radiochemistry and radiation services department.
NEA publishes real-time data of ambient radiation levels on its website. Singapore’s natural background radiation is about 0.1 micro-sieverts per hour, a negligible amount that is equivalent to eating a banana.
“We have established this baseline, which will eventually become the most sensitive meters that we can have. Over time, should there be nuclear power plants deployed in the region, if there is any incremental release (of radiation)... that’s what we want to spot,” Mr Ang added.
NEA is also part of the ASEAN Network of Regulatory Bodies on Atomic Energy, which established a regional early warning network in the event of nuclear or radiological incidents.
More than 80 monitoring stations are installed across South-east Asia, with data shared on a platform for the countries to access. Singapore’s monitoring network is connected to the system.
“Through that we will know (if radioactive substances) have been released, and we will know it early, and can internally prepare a response plan,” said Mr Ang.
Beefing up nuclear safety
As Singapore’s radiation and safety regulator, NEA established a nuclear safety division
The division, part of the group headed by Mr Ang, currently has two main roles.
One is to raise the team’s capabilities to properly assess the safety of various nuclear reactors, and the other is to have its eyes on atomic developments in the region.
“Safety assessment is not just (knowing) reactor technology,” Mr Ang explained.
“It’s the whole end-to-end life cycle of nuclear installation, from the design to the siting, commissioning, operations, down to the end of decommissioning and waste management.”
Mr Ang Kok Kiat, NEA’s group director of radiation protection and nuclear science group.
ST PHOTO: KEVIN LIM
The team needs the technical and scientific knowledge to engage Asean counterparts and build cooperation in a “science-grounded manner”.
Mr Ang, who did not reveal the staff strength of the new division, said it is still expanding.
Officers have been sent to pursue postgraduate studies in nuclear engineering overseas, while some have been sent for professional training, he added.
Recently, two staff members visited a nuclear plant in the United States to learn how the Nuclear Regulatory Commission there conducts safety inspections.
Mr Matthew Chew, nuclear competency and strategy lead at engineering consultancy HY, said it is important for Singapore to participate in such drills and proficiency tests to show that the Republic has mastery in radiological safety and is prepared for emergency response.
“This highlights that Singapore is ready to step up and do our part in the unlikely event of a nuclear incident in our region,” he added.
Mr Chew added: “Having a strong technical team within the regulator will put Singapore in a credible position within ASEAN, to regularly engage the bloc at a deeper level.”
On the hunt for radiation
The Straits Times outlines how NEA’s lab uncovers and measures radioactive particles, as part of the proficiency test.
Over the years, the UN agency has sent the lab items such as a tub of crushed vegetation and bottles of water spiked with varying amounts of radioactive particles.
Deputy principal scientific officer June Ong runing a swab test to check for contaminants on proficiency test samples from IAEA in the lab on Jan 27.
ST PHOTO: KEVIN LIM
The swab is run under a contamination monitor.
ST PHOTO: KEVIN LIM
1. Checking for leaks
When the parcel arrives, a swab test is done on the cardboard box and the items to ensure there were no spills en route to Singapore.
A contamination monitor reads the swab.
2. Detecting gamma rays
Highly energetic gamma rays are one of three main types of radiation emitted by radioactive elements, and they can penetrate the human body.
The gamma-ray spectrometer in the lab.
ST PHOTO: KEVIN LIM
The items are run through a spectrometer, which identifies what radioactive materials are present by measuring the specific energies of the gamma rays emitted.
3. Teasing out other radioactive substances
The other main types of radiation are alpha and beta particles.
Unlike gamma rays, these particles are easily stopped by thin materials and cannot reach detectors.
To detect them, samples must be specially processed – from drying to dissolving them in special solutions.
a) Concentrating tritium from seawater
Scientific officer Daryle Toh conducting distillation of seawater samples to isolate tritium.
ST PHOTO: KEVIN LIM
A distillation process purifies the water sample by removing impurities like dissolved salts.
Some of the purified water containing tritium – which gives off beta radiation – is collected for testing.
Most nuclear power plants routinely release treated water containing
low concentrations of tritium
, as part of normal operations.
b) Extracting other radioactive substances
A demo of solid-phase extraction.
ST PHOTO: KEVIN LIM
A process called solid-phase extraction isolates other radioactive substances like strontium-90, uranium and thorium isotopes.
The dissolved vegetation and seawater samples are passed through columns filled with filter-like materials that capture specific radioactive elements.
The retained elements are then washed out using acids, and collected for testing.
These are two of several methods used by the lab to isolate alpha- and beta-emitting substances.
4. Measuring the isolated substances
Containers of isolated substances like tritium in the liquid scintillation counter.
ST PHOTO: KEVIN LIM
Vials of substances such as tritium and strontium-90 are run through a machine called the liquid scintillation counter.
The machine may run for extended periods, sometimes multiple days, to measure the radioactivity, especially for samples with very low amounts of activity.
