Alalu and others,
That near miss in 1961 has been documented over 15 years ago in a book by Howard Mooreland called "The Secret That Exploded."
In Howard Moorland's book he outlines the number of accidents and near misses that the USA has had with nuclear weapons as well as nuclear reactors used commercially. Browns Ferry, in Alabama, of course Three Mile Island, and also The Fermi Plant outside of Detroit.
When I saw that story being reintroduced back into the news I realized immediately that it was more scare tactics to keep people thinking a certain way and of course ....being AFRAID
of any shadow they wanted to throw at us. I have known about it for about 15 years.
Also I have known about the loss of the hydrogen bombs from the mid air refueling accident and how one of them was found off the coast of Spain as well as one on Spanish soil.
THe sensors ...of which you speak..I have been around gamma alarms several times as well as radiation friskers..or portal monitors. Observed people doing a weekly testing on all this gear..including the gamma alarms. A different high energy shielded source is used in testing gamma alarms. You only expose it long enough to set off the alarm for testing then quickly reshield it.
I did not get excited over the news or any of that stuff when the buisness went down in Fukashima , Japan. Not that I was not concerned and observant..but I was not chaffiing at the bit or afrighted as were many Americans.
I carry in my bag to and fro work daily a bottle of Potassisum Iodide..had some for years now before the Japanese incident. Never opened it or used it but it is there. I have since purchased several other bottles. It became suddenly difficult to find when Fukashima went down. Best get yours now..in better times than in a sudden rush. But be careful about taking it..unless you really need to use it. Also about giving it to children.
I also know the Japanese have had an accident or unplanned criticallity at a fuel processing plant which killed two or three fellows back about 10 to 15 years ago. There was a rapid news blackout and cover up back then too.
Unlike so many Americans..I am not going to jump through but so many hoops.
Most people around here with a television and movie education...have no idea how many operating nuclear reactors are going at any one time. They only think around here of the Surry and North Anna commercial plants ..but never think how many are operating at any one time across the bay at the Norfolk Navy Station. SAme thing in San Diego...or up around Everet, Washington or Bremerton. How about around Portsmouth, New Hampshire...Honolulu, Hawaii????
Most Americans ...once again..with a television and movie education have no concept of how many dangerous and nasty items or chemicals are moving through their towns and cities at any given day. Probably best that most of them never know. To many drama queens out there who want someone else to take the RISK out of life for them while they watch television and movies....worship the gods of sports and Joan Rivers et al.
Nuclear materials are shipped daily across this country somewhere ..on a very confidential schedule and on specially managed and secured trains. They are shipped to special destinations where the materials are processed. Certain other special nuclear materials are moved on even more secure trains with an even more highly classified schedule and routing/monitoring. These materials are now handled with the Department of Energy, Department of Transportation, and now Department of Homeland Security.
Nuclear materials are not the only items shipped in this manner..there are others.
Radioactive dirt??? Where do you suggest they put it??? Transport it??
I have seen the photos of the reactor plants removed from olde submarines and placed in huge pipes..welded up...and put into a landfill or storage location..with berms around it..some forty plus olde reactor vessels. The submarine hulls long since scrapped.
IF you look at Bremerton, Washington at the Navy Yard on Google Earth...you will see some 11 or 12 submarines tied up side to side...like sardines. Most of them but one are olde early model 688 hulls....but one of them seems to be an olde 637 class boat...but definitely not a 688. All of them waiting to be scrapped. Where do you think they are going to put the still highly radiated and contaminated reactor vessels and reactor coolant pumps?? I've seen a coolant pump..several of them ...removed from a submarine an placed into a piece of pipe..welded with thick plates on each end ..then shipped out to a storage location.
Most Americans never think about such things..but I do. I dont spend alot of my time concering myself with what is on television or sports...the Redskins, Dallas, or NASCAR. Nor do I concern myself with what Joan Rivers and her Daughter are doing on the red carpet.
As to the detonation of these weapons..I believe they were not satisfied with several of the components or reliability of them in the early models. There was a learning curve. I believe much of this has been miniaturized today...compacted down into smaller sizes and power consumptions to get them going...verses the early designs. Howard Mooreland hints at this in his book.
Also Howard Mooreland speaks of a system put into some of these weapons called...."Dial A Yield." A system where the Hydrogen Enhancement was able to be dialed up or down to raise or lower the Yield of the explosion as needed. This is also another reason for extensive testing. The safety and reliability of these systems.https://en.wikipedia.org/wiki/Dial-a-yield
More reliabily. I also know that the delivery systems are much more accurate. The days of weapons needed in the megaton ranges are over. Usually with todays accuracy in the kiloton yeilds will do for most. SAme with conventional guided weapons ..high weight conventional bombs/rockets are used only for the most hardened targets. The main reason for the high yield weapons in the past was that the deivery system was not that accurate in the early days hence the inaccuracy was made up by larger yield bombs. Howard Mooreland also discusses this aspect of these weapons.
I am sure it took some time and research to get dial a yield to where it was more reliable and successful.
Hope this helps,