In 1951,a physicist tasked with designing an early thermonuclear bomb, has a lesbian affair with her young lab assistant.She’s determined to complete the difficult design while struggling for survival when she discovers her lover to be a ruthless Soviet spy

There appear to be two potential plots here;

1 - Lover turns out to be a spy and the scientist must choose to either turn her in or save her then act on her choice. = inciting incident is spy discovery her goal is to protect the love interest.

2 - A hydrogen bomb is needed the scientist must fight bigotry and sexism to achieve her goal of creating a bomb.= inciting incident is given the task to create a bomb, her goal is to make a bomb.

Best you chose one of these as the central/A plot and focus the logline accordingly.

I think the logline needs to clarify the central dramatic problem facing the scientist.

What dramatic problem arises as a result of her lesbian relationship? ?Isn't ?it the threat of blackmail, being exposed as a lesbian which in those dark ages of paranoia and prejudice would destroy her career?

And what does the spy want from the scientist that she isn't already getting by working on the inside as a lab assistant?

The "early thermonuclear bomb" being developed at that time (1951) was the hydrogen bomb. ?So just call it for what it was. ?

Finally, thermonuclear bombs were far too complex to be designed or built as solo efforts. ?It took a team effort. ?So she would not have been tasked to design it all by her lonesome which is the impression the logline seems to give. ?It would be accurate to say she was a member of team building the hydrogen bomb.

I think the logline needs to clarify the central dramatic problem facing the scientist.

What dramatic problem arises as a result of her lesbian relationship? ?Isn't ?it the threat of blackmail, being exposed as a lesbian which in those dark ages of paranoia and prejudice would destroy her career?

And what does the spy want from the scientist that she isn't already getting by working on the inside as a lab assistant?

The "early thermonuclear bomb" being developed at that time (1951) was the hydrogen bomb. ?So just call it for what it was. ?

Finally, thermonuclear bombs were far too complex to be designed or built as solo efforts. ?It took a team effort. ?So she would not have been tasked to design it all by her lonesome which is the impression the logline seems to give. ?It would be accurate to say she was a member of team building the hydrogen bomb.