Development and Results of a Test Program to Demonstrate Compliance with IEEE STD 384 and R.G. 1.75 Electrical Separation Requirements

The IEEE Std 384-1974, entitled ``Criteria for Separation of Class 1E Equipment and Circuits,´´ contains criteria to ensure the independence of redundant Class 1E equipment when designing electrical systems in nuclear plants. The NRC, in R.G. 1.75 Rev. 2, 1978, endorses, with comments, IEEE-384, as the means of achieving independence. One method given in IEEE-384, is that of maintaining a specified separation between components; another method utilizes a combination of separation and barriers. The standard also allows alternative methods to be used when justified by test-based analyses. This paper is a report of a test program undertaken to provide a basis for analysis in the development of alternative methods of achieving separation. The test parameters developed and used, and the results obtained, should prove useful in determining alternative methods of complying with R.G. 1.75 requirements. It should be noted the results of these tests are highly dependent on the type of cable used and the fault current assumptions.