Jeffrey LewisSyrian "Copy" of Yongbyon?

So, I’ve been keeping my powder dry on this story by Sanger and Mazzetti claiming that Israel struck “a partly constructed nuclear reactor, apparently modeled on one North Korea has used to create its stockpile of nuclear weapons fuel …”

I’ve been reading carefully, going back over the historical data, trying to make sense of a story that, frankly, confuses me. Today, the Times runs a correction:

An article on Monday about the refusal of Israeli officials to confirm or deny a report in The Times that the Israeli Air Force had bombed a Syrian facility on Sept. 6 overstated the conclusion Israeli and American intelligence analysts had drawn about the target. While they judged the facility to be a partly constructed nuclear reactor, they said it was of apparent North Korean design; they did not say so definitively.

[A colleague points out that the correction is for a story by Steven Erlanger that asserts Israel “bombed a partly constructed nuclear reactor apparently of North Korean design.”]

Yeah, I was waiting for that — I spent the better part of a couple of days looking into the question of when (and how) the US determined the design of the Yongbyon reactor. As far as I can tell, in the early phases of construction, the ability to correctly identify reactor types is less than a science.

I am willing to accept that the Israelis might believe they knocked out a “Yongbyon next-door” but I am not willing accept their judgment based on the evidence that has been presented in public.

When Would We Know What Kind?

To illustrate my point, here is a timeline showing US intelligence assessments of the North Korean 30 MWth reactor at Yongbyon (sources at the end of the post):

  • 1980: US spy satellites identify reactor components co-located with a large hole dug for the reactor’s foundation.
  • April 1982: US spy satellites spot a reactor vessel at Yongbyon. In July, the CIA incorrectly describes the new reactor was a “copy” of the Soviet-supplied 2-megawatt thermal research reactor “not designed to produce quantities of plutonium needed for a nuclear weapons program.”
  • March 1984: US spy satellites spot a cooling tower under construction, suggesting a much larger reactor. In April, the CIA would report that the reactor “probably will be graphite-moderated and use natural uranium for fuel.”
  • 1986-1987: The 30 MWth Yongbyon reactor goes critical.

If the Syrian “reactor” was years from completion, then the situation is comparable, I think to the 1980-1984 period when the IC was mistaken about the reactor design.

It fairly boggles the mind that one could confidently determine the Syrian facility was a “copy” of the reactor at Yongbyon when, at a comparable stage of construction, we failed to correctly identify the Yongbyon reactor itself.

Of course, we may have learned a trick or two since then — one might imagine that we now look for tell-tale signs of Yongbyon-like reactors (such as the thickness of the concrete “biological shield” that should provide clues to the neutron flux or the layout of the facility).

But the debate over the intelligence, however, suggests otherwise.

Yongbyon Was A Copy, Too

Yongbyon is a sensational reference point from a news perspective, but the North Korean reactor is itself derived from the Calder Hall magnox reactors developed by Britain. Comparing the Syrian reactor to Yongbyon, without mentioning Calder Hall, leaves the reader thinking the reactor design could not have been supplied by any another state and was certainly not indigenous.

But Syria might have chosen the Calder Hall design for the same reasons as North Korea — the reactor is a relatively simple design that is extensively described in the open literature and does not require difficult to acquire heavy water or enriched uranium. It is perfect, in many ways, for the DIY bomb-builder.

A 1991 news article documents all of these important aspects that Sanger and Mazetti omit — the design heritage of Yongbyon, the information that might be in the public domain and the value of not using heavy water:

In the late 1960’s, having already acquired a miniature reactor from the Soviet Union, the North decided on a a design for a 1950’s-era British reactor called “Calder Hall,” still operated by the British Nuclear Fuels Company, according to published accounts in the nuclear trade press and one intelligence official.

There are disagreements about whether enough details of the reactor’s design were available in public documents to give North Korean scientists the outlines of what they needed, or whether classified details leaked. But the reactor uses graphite to modify, or control, the nuclear reaction — and graphite is something the Koreans could produce at home. That would eliminate the need to import heavy water, or deuterium oxide, a highly controlled substance.

The author was, of course, David Sanger.

Sources on Yongbyon: Oberdorfer, The Two Koreas: A Contemporary History, 2002, 250; North Korea and Nuclear Weapons: The Declassified U.S. Record, National Security Archive Electronic Briefing Book No. 87, edited by Robert A. Wampler, April 25, 2003; Wit, Poneman and Gallucci, Going Critical: The First North Korean Nuclear Crisis, 2004, 1; Richelson, Spying on the Bomb: American Nuclear Intelligence from Nazi Germany to Iran and North Korea, 2006, 246-247.


  1. FOARP (History)

    Of course, one other important thing about Calder Hall was that it was a dual-use facility being designed both for electrical production and Plutonium production. This makes it an atractive design for propaganda purposes as well as allowing the option of ‘demilitarising’ the plant in exchange for concessions and then ‘remilitarising’ it a later date for another bite at the cherry.

  2. Lao Tao Ren (History)

    Oh Judith… (Miller, not Guiliani) where are you when the NYT needs stories like this?

    You haven’t gotten into business with Jayson Blair, have you?

    The Times may need you back!

  3. China Hand (History)

    I’ve come around to the idea that Israel presented a nuclear, not SCUD, dossier to Washington to justify the raid. If so, the dossier doesn’t appear to have been very convincing in portraying an imminent threat justifying a pre-emptive strike. Judging from Jeffrey’s post, there might have just been a suspicious hole in the ground and little else. I think the protracted debate in Washington had more to do with some people wanting to structure our relations with Israel and policy in the Middle East around the idea of an existential and metastasizing proliferation crisis now involving Syria—to counter other peoples’ theory that the Middle East’s nuclear problem could be managed effectively a la North Korea: by more direct engagement between Teheran and Washington, an approach which would marginalize and subordinate Tel Aviv. In other words, the North Korean spectre Israel saw in the desert was not the shadow of another Yongbyon reactor—it was the possibility of the U.S. addressing the Iran situation by imposing a Six Party Agreement-style structure on Israel. I give my reasons here

  4. b (History)

    What makes you think that this was a nuclear site at all???

    So far there are only Israeli sources claiming so and US sources who say “based on Israeli intelligence …”

    Any reason to believe these are true at all?

  5. Alex (History)

    The other important thing about Calder Hall was that it was a rush job that very nearly blew up. There was a reason we moved on to magnox and AGRs.

  6. MK (History)

    Hi Jeffery. I’ve been lurking within, on and off, for some time now. Love the place you’ve created here…even though most of it flies far over my head!

    Unless I’ve missed something (quite possible) it looks as if you are saying the Israelis bombed a shipment of scuds and not a reactor.

    Do you think they knew what they were bombing, and are happy to let the rest of the world and the media speculate sensationally about the target?

    (Elementary question, I’m sure. Please forgive.)


  7. James (History)

    My understanding about that period of reactor design was that both the British and the French were eyeing the export market. They were looking for a relatively simple plant that operated at low pressures and could be built with local labor.

    These were selling points for newly liberated colonies that were wary of being overly dependent on their former masters. The nuclear industry was going to displace the oil business as the primary power source and the European nations, playing catchup behind the Americans, were anxious to find an angle that would appeal to a mass market.

    Ah, the dreams they had then…

  8. Andrew Foland

    In the first go-round, we heard that the raid was on a nuclear plant for extracting uranium from phosphates. This round it’s a nuclear plant for plutonium production.

    Seems to me there’s something of a fixation on it having been “something nuclear”.

    In the next round will we hear that it was a lab that was on the verge of weaponizing Californium?

  9. Richard F.

    Just a general remark. In all the speculations about the target it is assumed Israel saw ‘something’ on satellites and was misguided. I bet it is fair to assume israel intelligence in syria is more than visual overflights …

  10. blowback (History)

    The other important thing about Calder Hall was that it was a rush job that very nearly blew up. There was a reason we moved on to magnox and AGRs.

    — Alex · Oct 19, 06:33 AM

    You are correct in stating that Calder Hall was dual use but wrong in stating that it was a rush job that very nearly blew up. The 4 Calder Hall reactors were the first of the Magnox design. The “rush jobs” were the two Windscale Piles which were air-cooled graphite-moderated reactors used purely for producing military-grade plutonium and other radioisotopes. Windscale Pile No 1 caught fire on 10th October, 1957.

  11. Richard F.

    So abc (
    is having it that the reactor was some 100 miles from the Iraqi border and since it takes more than a blower to cool, you need something like the Euphrate. This gives the second coordinate and you end up with 35.7846°N, 39.5586°E, give and take some 10 miles or so. Who is doing some geocaching to find the egg ?

  12. Akash (History)

    Jeff, breaking news!!
    How did you miss this?

    Yet another nation joins the Nuke armed nations ..

  13. spacemanafrica

    Richard, I put this together Sept. 19th or so. Everything points to this as the site, including Israeli media.

    It may download as a .zip, change the extension to .kmz for use with google earth.

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