This article describes a study that examines standards, draft standard
s, and guidelines (all of which will hereafter be referred to as docum
ents) that provide requirements for the assurance of software in safet
y systems in nuclear power plants. The study focuses on identifying, f
or developers of standards, the elements to be addressed in a standard
for providing reasonable assurance of software in safety systems in n
uclear power plants. The documents vary widely in their requirements a
nd the precision with which the requirements are expressed. Recommenda
tions are outlined for guidance for the assurance of high-integrity so
ftware.