The high-power unit had 300 grams of Pu-238 in 1965. Given its 87.7 years half-life, only 187g of Pu-238 remaining. It's very hard to do much damage with this amount of radioactive material.
U-234 is ~3000x less radioactive than Pu-238, so having ~120g of U-234 is negligible.
I really fail to see a problem with these tiny amounts of non-brittle material embedded into a solid case. It's still very dangerous, but it's locally dangerous (meters away), not at the scale of whole countries.
The high-power unit had 300 grams of Pu-238 in 1965. Given its 87.7 years half-life, only 187g of Pu-238 remaining. It's very hard to do much damage with this amount of radioactive material.