On an interesting aside to this issue…
U-234 surrendered at Portsmouth, New Hampshire on May 16, 1945. U-234 departed from Norway on April 16, 1945. While at sea in the North Atlantic, U-234 learned of the surrender of Nazi Germany. Two Japanese Officers aboard committed suicide.
The cargo of U234:
one ton of diplomatic and personal mail
technical drawings and blueprints for advanced combat weaponry
anti-tank weapons
advanced bombsights and fire-control systems
airborne radar
an Me 262 jet fighter
additional jet engines
560 kilograms of uranium oxide
Additionally the U-234 carried the following top Nazi experts.
Luftwaffe General Ulrich Kessler, on his way to become German air attache in Tokyo
Luftwaffe Lieutenant Colonel Fritz von Sandrart and Lieutenant Erich Menzel, experts in air communications, airborne radar, and AA defenses
Four Kriegsmarine officers, including a naval aviation expert, an AA expert, a naval construction engineer, and a naval judge (whose job would be to finally stamp out the last vestiges of the Sorge spy ring)
August Brinewald and Franz Ruf, experts in the technology and construction of jet aircraft whose mission was to begin production of Me 262 jet fighters in Japan
Dr. Heinz Schlike, a specialist in radar and infrared technologies
The U-234 however, was destined for Japan. The uranium oxide cargo was intended for Japan's uranium enrichment project at Hungnam in northern Korea under the direction of Dr Nishina.
Almost nothing is known about the Japanese operation at Hungnam as it fell into Soviet hands at the end of WWII. There have been persistent rumours since the end of WWII that the Japanese conducted some sort of small ('fizzer'?) atomic weapon test in the sea of Hungnam on 12 August 1945.
ANdy