1. What does it take for the DPRK to be a nuclear threat?
Jerry Peterson
Department of Physics
University of Colorado

3. There is a secret to nuclear bombs!

4. The Secret to the Atomic Bomb?
That’s not it.

5. The Secret to Nuclear Bombs
They work!
Plan A
Plan B
The Super

6. Nagasaki Plan B
Hiroshima Plan A

7. Ground zero of the first Soviet A-test, August 1949.
Plan B

8. Proliferation
Currently: USA, Russia, United Kingdom, France, PR China, India, Pakistan, North Korea, (and Israel)
Have thought about it: Canada, Sweden, Switzerland, Brazil, Argentina…
Have given them up: South Africa, Kazakhstan, Ukraine, Belarus
Active programs? Iraq, until we ended it. Iran?

9. Uranium is 0.7% 235U and 99.3% 238U neutron Excited nucleus, shaking
Two fission fragments and 2.4 neutrons
Like charges repel—the origin of heat energy

10. Fission, just like a lava Lamp

11. The hardest part of getting a nuclear bomb is the material
“Front End”- obtain 235U (HEU=at least 80%) by exactly the same methods used to make Low Enriched Uranium (LEU) for power plants (typically 3-4%) from natural uranium, 0.7% of which is 235U.
“Back End”- obtain 239Pu from Spent Nuclear Fuel by chemical reprocessing.

13. The plutonium route-Plan B
Construct a nuclear reactor, operating from the fission of 235U. The operation of the reactor can be monitored by satellite.
Allow the excess neutrons available from this fission to capture on abundant 238U to breed 239Pu. (arithmetic: 238+1=239)
Separate the plutonium and uranium by ‘reprocessing’ chemistry, which releases radioactivity that can be sensed.
Create a fission bomb from this material.

14. DPRK summary
Began construction of nuclear reactors and associated technology from late ‘50’s, Yongbyon reactor operational 1986, making ~6 kg Pu/year using natural uranium.
Signed NonProliferation Treaty 1985—allows peaceful development
Withdrew from the NPT on 2003, and expelled IAEA inspectors in 2002.
Known to be developing nuclear bomb technology, via the plutonium route= Plan B.
Yongbyon components destroyed 2008, restarted
Evidence of uranium enrichment 2010 (Pakistan), Plan A
Lots of uranium ore32,000 tons of uranium

15. The context
NPT
US removed all nuclear weapons from Korea in 1991, in ROK since 1958, up to 950! In 1967.
Six Power talks—not just nuclear
Agreed Framework—
Freeze plutonium program, in return for fuel oil and a promise of two LWR for power.
LWR concrete poured 2002, suspended.

16. You can’t hide any significant nuclear effort.
Satellite images, including heat sources
Seismology
Radioactivity—very sensitive and specific.
Laws of physics—extrapolations.

17. Yongbyon

18. Yongbyon facility

19. Now operating again
S. Hecker

20. Second one-2009, a few kilotons of TNT equivalent, but no leakage.
Test the device
As we did in 1945.
First (underground) 2006, sensed by seismology. A ‘fizzle’, but enough radioactive leakage to sense.
Second one-2009, a few kilotons of TNT equivalent, but no leakage.
Number 6-September 2017

24. #6--The ‘Super’?
A hydrogen bomb uses a fission bomb ‘trigger’ to initiate fusion reactions among isotopes of hydrogen, for an unlimited yield.
The trigger supplies enough pressure and temperature to allow two positive hydrogen nuclei to react.

25. But-like charges repel !

29. Future? Inventory—20-40 kg Plutonium 200-450 kg HEU
-enough for ~20-25 weapons
Production for ~6/7 weapons per year
S. Hecker/ Bulletin of the Atomic Scientists

30. (convertalot.com/earthquake power calculator.htm)
How big was #6? 3 September 2017
Richter 5.7=5.4 kT
Richter 6.3=42.5 kT
(Hiroshima 14 kT)
(convertalot.com/earthquake power calculator.htm)
Hecker-perhaps 100 kT

31. Ivy Mike 10 Mt “Science seems ready to confer on us, as its final gift, the power to erase human life on this planet” DDE first inauguration, 1953

32. Nuclear Bomb Effects, by Testing
Surface, air, underground, undersea, in space
USA—1054
The effects are experimentally known!
Brian Toon, the expert