(Above and at article top:) The military wing of the Gaza-based Islamic Jihad terror group releases a video threatening rocket attacks on the nuclear reactor in Dimona and other sensitive sites in Israel, May 4, 2019. (Screen grab)
(Above and at article top:) The military wing of the Gaza-based Islamic Jihad terror group releases a video threatening rocket attacks on the nuclear reactor in Dimona and other sensitive sites in Israel, May 4, 2019. (Screen grab)
ToI investigatesDo rockets, quakes and old age threaten Israel's core?

Israel’s Dimona nuclear reactor isn’t Chernobyl, but does have vulnerabilities

A disaster at Israel’s reactor would be far less catastrophic than the 1986 meltdown, but the core is being kept in service far longer than intended, and experts warn that’s risky

Judah Ari Gross is The Times of Israel's military correspondent.

The hit television miniseries “Chernobyl” has reminded the world of the ever-present specter of a nuclear catastrophe made possible by the deadly combination of negligence, ignorance and incompetence.

On April 26, 1986, one of the four nuclear reactors at Chernobyl suffered a catastrophic power surge during a spectacularly mismanaged safety test. The resulting explosion and fire sent plumes of radioactive isotopes throughout the area, since the power plant lacked a containment structure. Contamination spread through large parts of the Soviet Union and Europe. Estimates put the long-term death toll at anywhere from 4,000 to over 93,000; the 1,000 sq. mile exclusion zone around the reactor remains one of the world’s most radioactively contaminated areas.

The Chernobyl disaster is one of two nuclear incidents to receive a level 7 designation on the International Nuclear Event Scale, indicating a major accident with widespread ramifications. The second was the earthquake-sparked 2011 Fukushima nuclear reactor disaster in Japan.

The effects of the reactor explosion are still seen and felt today, inside the exclusion zone and far beyond, with a still unfolding impact on people, wildlife and plants. Notably, hundreds of thousands of so-called liquidators risked their lives and long-term health to contain the radiation after the explosion, including some 1,500 who live in Israel and are woefully neglected by the government.

An aerial view of the Chernobyl nuclear power plant, the site of the world’s worst nuclear accident, is seen in April 1986, made two to three days after the explosion in Chernobyl, Ukraine. In front of the chimney is the destroyed 4th reactor. (AP Photo)

Could such a catastrophe occur in Israel’s own nuclear reactor, the Shimon Peres Negev Nuclear Research Center outside Dimona, in the south of the country? In a rocket strike on the facility — which Iran, Hezbollah, Palestinian Islamic Jihad, Hamas and Syria have each threatened or attempted to carry out — would large swaths of the Jewish state become contaminated with radioactive material? Or what about in a large earthquake along the Syrian-African rift, which is expected at some point in the coming years?

Fortunately, experts say, the simple answer is no.

Dimona and Chernobyl are of vastly different scales and models, and they serve vastly different functions. As a result, the potential for damage in southern Israel is orders of magnitude smaller even in a worst-case scenario, the experts say.

The same is true of the Soreq Nuclear Research Center outside the central town of Yavne, the core of which is even smaller than Dimona’s.

However, there are safety concerns connected to Dimona — namely that its core is aging, and will nevertheless continue to be used as Israel is unlikely to get a new one — and these often go undiscussed in public due to the largely classified nature of the facility, which produces fissile material for nuclear weapons, according to foreign media reports.

View of the nuclear reactor in Dimona, southern Israel, August 13, 2016. (Moshe Shai/FLASH90)

Israel is believed by foreign governments and media to be the Middle East’s sole nuclear power, but has long refused to confirm or deny that it has nuclear weapons, and officially maintains that the Dimona plant focuses on research and energy provision.

Dimona isn’t Chernobyl

The Vladimir Ilyich Lenin Nuclear Power Plant outside Chernobyl supplied 10 percent of the electricity requirements for Ukraine. Its four reactors produced 12,800 megawatts of thermal output and 4,000 megawatts of electricity.

As a result of this high level of energy output, the secondary explosion of its reactor in 1986 was estimated to be similar to that of 10 tons of TNT.

Poster for ‘Chernobyl,’ the 2019 HBO miniseries. (HBO)

The Shimon Peres Negev Nuclear Research Center, named for the former president who worked for its creation in the 1950s as director-general of the Defense Ministry, comes nowhere close to that level of energy production. The precise thermal output of its far, far smaller nuclear reactor is not known, but has been estimated at between 26 and 150 megawatts — or between 492 and 86 times less than Chernobyl’s — according to the Arms Control Association, a US-based nonproliferation group.

(The Soreq facility’s core, which was given to Israel by the United States, produces just five megawatts of thermal output.)

This massive difference in size results in a massive difference in the potential for damage.

During the 1967 Six Day War, Israel’s air defense batteries shot down an Israeli fighter jet that accidentally strayed too close to Dimona after it was damaged when flying over Jordan

Dimona, unlike Chernobyl, was built with a containment structure meant to prevent radioactive material from escaping in the case of a meltdown or other disaster. A metal-and-concrete structure known as a sarcophagus was constructed around Chernobyl after the fact.

In addition, the Shimon Peres Negev Nuclear Research Center has been under threat almost since its construction, which has necessitated the Israeli government to put its safety (and thus the safety of those living nearby) at a premium.

During the 1967 Six Day War, these air defense batteries shot down an Israeli fighter jet that accidentally strayed too close to the sensitive site after it was damaged when flying over Jordan.

A memorial sign to builders who made the first hastily constructed sarcophagus over the 4th reactor destroyed in the 1986 fatal explosion stands at the Chernobyl nuclear plant, in Chernobyl, Ukraine, Friday, April 20, 2018. A reactor at the Chernobyl nuclear power plant exploded on April 26, 1986, leading to an explosion and the subsequent fire spewed a radioactive plume over much of northern Europe. (AP Photo/Efrem Lukatsky)

The reactor, which was constructed below ground for added protection, is still guarded by a myriad of air defense units, which remain at the highest alert during periods of heightened tensions.

In 2007, amid peak fears of Syrian retaliation after Israel destroyed the country’s nuclear reactor, a commander of a Patriot missile defense battery guarding the site told Israeli television that any aircraft that “deviates even slightly from its route, sets off an alarm and risks [an interceptor] missile being fired.”

The Dimona core also has in place a series of earthquake protection measures, Eli Abramov, then-deputy director general of the reactor, told US officials in 2007, according to a WikiLeaks document.

In 2018, in rare public remarks, the head of the Israeli Atomic Energy Commission, Ze’ev Snir, said the country had been reinforcing the Dimona nuclear reactor in light of threats made by Iran and Hezbollah.

“We cannot ignore the repeated and explicit threats made by Iran and its proxies to attack Israel’s nuclear sites,” he said.

“These outrageous threats require Israel to take action and continue to protect and defend its nuclear facilities. These facilities are constantly upgraded and reinforced, in line with IAEA safety guidelines, in order to withstand any attack,” Snir said.

(Above and at article top:) The military wing of the Gaza-based Islamic Jihad terror group releases a video threatening rocket attacks on the nuclear reactor in Dimona and other sensitive sites in Israel, May 4, 2019. (Screen grab)

But almost as important as the vastly smaller size of Dimona, and the active and passive defense measures in place around it, is the fact that it is a research reactor, not a power plant.

Electricity-producing nuclear reactors, by their nature, are meant to be cost-effective. Any interruption of their output comes with a tremendous price, both in money lost and in the effect on the surrounding populations that rely on its power, which becomes a factor in deciding whether or not to shut down the reactor.

The Dimona nuclear reactor as viewed from satellite (photo credit: courtesy of United States Government)
The Dimona nuclear reactor as viewed from satellite (United States Government)

Not so in Dimona, where all operations can be halted immediately at any sign of trouble, without fear that such a move will cause large portions of Israel to go dark, according to an expert who asked not to be identified.

Modern reactors can also be taken offline rapidly by flooding the reactor with boron, an element that is able to absorb the neutrons released by nuclear fission.

This does not immediately remove all danger, but within minutes it can stop the reactions inside the core and allow the reactor to begin to cool down. The expert compared this to removing a boiling kettle from the stove: The water inside might still be hot, but it is no longer boiling and can start returning to room temperature.

“A competent operator will, at the first sign of trouble, shut down the reactor,” he said.

This could be at the first alert of an incoming rocket or missile from Syria, Iran or Lebanon, an initial indication of seismic activity ahead of an earthquake, or a case of a malfunction in the reactor.

A competent operator will, at the first sign of trouble, shut down the reactor

An emergency shutdown was not immediately performed in Chernobyl, and when it was belatedly executed, the shutdown process proved catastrophically flawed, which was central to the disaster. The reactor — a Soviet RBMK model, which is seen as an inherently dangerous variety — entered a positive feedback loop, generating more power instead of less before it blew.

One of the other main issues following a nuclear accident or an attack is a loss of power to the reactor itself, which prevents operators from controlling the reactions inside.

This caused the 2011 Fukushima disaster in Japan when a tsunami knocked out the generators that fed power to the pumps that moved coolant through the reactor. This led to meltdowns and explosions. Two people were killed in the initial disaster, and six others were exposed to high amounts of radiation. The cleanup is expected to take 30 to 40 years.

In this Feb. 10, 2016 file photo, a member of the media tour group wearing a protective suit and a mask looks at the No. 3 reactor building at Tokyo Electric Power Co’s (TEPCO) tsunami-crippled Fukushima Dai-ichi nuclear power plant in Okuma, Fukushima Prefecture, northeastern Japan. (Toru Hanai/Pool Photo via AP, File)

Following Fukushima, nuclear reactors began employing backups to their backups — large batteries in addition to fuel-powered generators — in order to ensure that they would always have a supply of electricity in the case of an accident.

The expert said he would not and could not say definitively what methods would be used to shut down Dimona or what backups are in place to provide it with power, but indicated that the above are reasonable assumptions.

What does an attack on Dimona look like?

In 2008, the non-proliferation Arms Control Association simulated a rocket strike on the Dimona nuclear reactor under the guidelines of the US Department of Defense’s Hazard Prediction and Assessment Capability (HPAC), a method of estimating the effects of a nuclear disaster.

As many specific details about the Shimon Peres Negev Nuclear Research Center are kept classified and subject to the military censor, this study acknowledges that it is only a rough approximation of the potential damage caused by a rocket attack on the facility.

In addition to the aforementioned unknown thermal output, the ACA’s Bennett Ramberg was unable to factor in the “potentially significant contributions that could come from on-site spent fuel and high-level waste from reprocessing or separated plutonium.” (In addition to a reactor, the Dimona facility also acts as a storage center for the entire country’s nuclear waste.)

According to Ramberg, a successful rocket attack on the reactor — one that manages to get past the site’s air defenses and breaches the site’s containment dome — would “disperse the heavy water surrounding the reactor core; and create explosions and fire involving the nuclear fuel elements, ejecting radioactive material into a puff carried away from Dimona by prevailing winds.”

Soldiers in the IDF Home Front Command perform an exercise simulating an atomic, biological and chemical attack in 2011. (Yuval Haker/Israel Defense Forces)

Counterintuitively, the ACA study found that a more powerful strike on the Dimona nuclear reactor could be a safer one. Such an attack could “so fracture and scatter the reactor core that the absence of concentrated fires would diminish the release” of radioactive material, Ramberg wrote.

The HPAC calculations determined that the deadliest time of year for an attack on the core would be during the month of February, when the seasonal winds would push the radioactive molecules released in an explosion toward the relatively high-population West Bank. There it could cause hundreds to over a thousand cases of cancer among residents of the area, depending upon the reactor’s level of thermal output.

According to Ramberg’s study, an attack in the summer would send these radioactive clouds away from Israel and toward Jordan’s “thinly populated south.”

However, as the countries and groups most expected to carry out such an attack would likely not be seeking to harm Jordanians or the mostly Palestinian residents of the West Bank, the ACA article sees late fall as the most likely time for an attack, not the winter or summer.

An attack in November would mean the fall winds would carry the “radioactive plume in a northwesterly direction over the city of Dimona (a community of 30,000 inhabitants) and then toward Beersheba before scattering toward Israel’s heavily populated coastal plain housing approximately four million inhabitants,” Ramberg wrote in 2008. The population sizes have not dramatically changed in the interim 11 years.

The ACA study found that the largest immediate problems following a successful strike on the Shimon Peres Negev Nuclear Research Center would come in the form of two main radioactive molecules: iodine-131 and cesium-137.

A doctor examines a boy who was evacuated from near the Chernobyl disaster area to Artek, June 14, 1986. (AP Photo)

Iodine-131 is a relatively short-lived but highly dangerous radioactive isotope that is produced in nuclear fission by plutonium and uranium. The molecule can collect inside people’s thyroid glands, causing cancer as it degrades over the years, making it deadlier for children than for adults, studies have found.

The molecule decays rapidly, making it a serious immediate problem but not a long-lasting one, and its effects can be significantly mitigated by giving those who come in contact with it large doses of a non-radioactive iodine compound, which dilutes the contents of the thyroid and thus minimizes the number of ionizing molecules.

Tablets containing such compounds — known as Lugol’s iodine — have already been distributed to residents of Dimona and the towns in the immediate vicinity of the Soreq reactor.

A woman mourns at the Chernobyl victims’ memorial in the Ukrainian capital of Kiev on April 26, 2016. (AFP PHOTO / Anatolii Stepanov)

Cesium-137 presents a significantly different challenge. This molecule remains in the environment for a far longer amount of time before it eventually breaks down. It is one of the main radioactive molecules that keeps the so-called “exclusion zone” of Chernobyl contaminated more than 30 years after the disaster.

In a nuclear catastrophe in Dimona, cleaning up this molecule — which can easily mix with groundwater and is readily absorbed by people, animals and plants — would present a significant challenge, requiring large amounts of resources. This radioactive molecule is still being found in marine life around Japan, some eight years after the meltdown at the Fukushima nuclear reactor.

The threat to humans is reduced by the reactor’s distance from populated areas. Due to the Dimona core’s relatively small size, the contamination would also likely be limited to the area immediately surrounding the reactor.

The Israeli military’s Home Front Command also maintains a unit specifically trained in rapidly responding to atomic, biological and chemical disasters.

Rocket attacks aren’t the only threat

In addition to the overt threats posed to the Dimona nuclear reactor by terror groups and enemy nations, as well as by earthquakes and other natural disasters, one of the less-discussed concerns surrounding the core is its advancing age and Israel’s apparent resolve to keep it running regardless, the expert said.

The Dimona nuclear core, which was given to Israel by France and went active in the early 1960s, is one of the oldest still operating in the world.

Originally designed to operate for 40 years, the core is now being pushed to remain in service for twice that, according to the expert.

A photo from the 1960s of the nuclear facility outside Dimona (Flash 90/US National Security Archive)

This is not from frugality or unwillingness on Israel’s part to purchase a new core, but a legal inability or disinclination by the countries that produce these cores to sell one to the Jewish state, as Jerusalem refuses to sign the Treaty on the Non-Proliferation of Nuclear Weapons, which is meant to prevent the spread of nuclear weapons.

As a result of Israel’s inability to replace the nuclear core, it is motivated to keep it in service for as long as possible, the atomic expert said, replacing and upgrading whatever parts it can and carefully monitoring the components it can’t for any possible “show-stopping” signs of trouble, notably in its aluminum reactor tank.

He compared Israel’s situation with the Dimona core to someone with a car they feel they need and can’t afford to replace.

“You would spare no effort in keeping it functional,” he said.

View of the Israeli nuclear reactor located in the Sorek valley in the Judean hills, December 15, 2011. (Yaakov Naumi/Flash90)

The initial four-decade expiration date for the Dimona core was based on the limits of the technology of the time. In the interim half-century, additional methods of monitoring the health of the nuclear core that have come into existence are being used to ensure that it can be safely operated for longer.

In April 2016, scientists at Tel Aviv University revealed 1,527 defects and flaws to the concrete-coated aluminum core using an innovative ultrasound technique that was performed first in 2007 and again in 2015. The scientists noted that none of these flaws had grown during that 8-year span. These defects were labeled and continue to be monitored to check if they get larger.

Tourism Minister Yariv Levin arrives at a Likud party meeting on May 28, 2019, in Jerusalem (Yonatan Sindel/Flash90)

“There is no maximum time for the reactor’s work. The continued operation of the facility is subject to compliance with clear and stringent occupational safety criteria,” Tourism Minister Yariv Levin said, speaking on behalf of the government in 2016, following the report.

“The ultrasound test performed at the reactor… was part of the strict maintenance procedures. This test did not indicate any problem in the reactor that would require it to cease operations,” he said.

Despite the government’s assurances, several Israeli nuclear experts — including some of the scientists who founded the Dimona reactor — as well as politicians have for years been calling for the aging core to be shut down over the risks it posed.

Uzi Even (photo credit: CC-BY-SA Bulusaristo/Wikipedia)
Uzi Even (CC-BY-SA Bulusaristo/Wikipedia)

Uzi Even, a chemistry professor at Tel Aviv University who was involved in the creation of the reactor, has been at the forefront of this charge, arguing that the core has outlived its usefulness.

“If you’re asking me if there is a point in continuing operating a 53-year-old reactor, the answer is certainly not,” he said in a 2016 radio interview, following the reports of the Dimona core’s 1,527 flaws.

The atomic expert did not call for the reactor’s immediate closure, but said it must be shuttered at the slightest problem with its irreplaceable parts.

“The things that you have to actively monitor — if there’s a problem, you have to shut it down. If irreplaceable parts are damaged, you must close the core,” he said.

One of the central issues regarding Dimona’s safety is that it has no independent oversight. Since Israel is a non-signatory of the nuclear non-proliferation treaty, the International Atomic Energy Agency do not inspect the site, nor do American inspectors, who did monitor the reactor in its early days until they determined that their checks were effectively worthless as many aspects of the site were being kept hidden from them. Instead, the reactor is monitored by Israel’s Atomic Energy Commission — the same body that is responsible for running it.

The highly classified nature of the work there also limits the amount of public debate about the nuclear research center.

Efforts to allow the State Comptroller’s Office, which performs independent investigations of various aspects of the government and military, to release its findings about the Dimona core have been blocked over the years by the Prime Minister’s Office on grounds that their publication threatened national security.

Indeed, a court order was required to allow the printing of a 2016 comptroller report, which dealt solely with the actions of the civilian company, Rotem Industries Ltd., that markets the commercial findings of the Dimona reactor — not with the functioning and safety of the nuclear core.

This secrecy and lack of independent oversight means Israelis (and to a lesser extent Jordanians) can only hope that the government is doing its all to prevent a nuclear catastrophe — albeit one that would be far smaller than Chernobyl.

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