Such accidents were not as uncommon as you may imagine. In the 1960s such things happened relatively frequently.
-16/4/1961: Tu-95 crashed 250 mi of Vladivostok. The aircraft was loaded with 4 7000lb nuclear bombs at the time of the crash.
3 of the 4 were discovered two weeks later. The forth was discovered 1 month later in a lake.
-8/12/1962: Tu-95 forced to drop 1 7000lb nuclear bomb 50 miles off Russian coast in the Sea of Okhotsk due to the failure of two of its engines and damage to the third engines prop. Bomb destroyed on impact. No explosion.
-19/2/1964: Tu-95 involved in a mid-air collision with a Sukhoi Su-9 over Bavhdar Lot, Kazakhstan. Rumoured that among wreckage were nuclear bombs.
The USSR were a lot less 'safety cautious' than most NATO nations when it came to nukes.
Info from a school book I forgot to return
