The Framatome Owners Group (FROG) has recently completed a technical program aimed at elaborating a generic document gathering the minimum set of requirements strictly necessary to be inserted in the Operating Technical Specifications document.
The main objective pursued was not to define a document meeting requirements of each Safety Authority but rather to propose a minimum set of requirements strictly required from a design standpoint in order to maintain an acceptable safety level during operation.
This technical program, which has been conducted during a two-year process, allowed to issue a document structured into four sections. The three first ones dealing with Definitions, Safety limits, Protection thresholds have been written on the bases of available information only for completeness of the document, and the fourth one devoted to Limiting Conditions for Operation has been based on a specific methodology approved by FROG Members. Rules for cumulative unavailabilities and preventive maintenance have been integrated in a simplified manner. Main bases retained for selecting the relevant specifications applicable to the 28 systems under analysis are mainly described in the US Federal Register (July 22, 1993).
This document includes some limitations, in particular it does not directly deal with surveillance requirements, specifications at cold shutdown conditions and extended fuel cycle. These issues will be discussed among FROG Members to examine if complementary analyses are needed or not.
Main results achieved through this program can be summarized as follows:
• It allows a better understanding among FROG Members of their respective needs and constraints, and it
allows to structure a methodological approach for addressing changes in the Operating Technical
• Although elaborated for a FROG generic unit, a consistent and coherent approach the most rational as
possible has been built allowing to establish the main justifications for each of the specifications.
• Despite the fact this report is not intended to be used as such in any licensing process, it draws the
standardized bases on which such licensing document can be prepared.
• It demonstrates the possibility to relax some existing specifications such as on ASG, PTR and REA systems.