Extending surveillance intervals for 24-month fuel cycles

Conference · Sun Jan 01 04:00:00 EST 1989 · Transactions of the American Nuclear Society, Supplement; (USA)

OSTI ID:5227766

Webster, S A; Drown, M T; Weinkam, E; Dryden, M

The past few years have seen a growing realization at utilities that a 2-yr fuel cycle for dual-unit plants makes a lot of sense from a planning perspective. Utilities with Combustion Engineering (C-E) nuclear steam supply systems have been encouraged to implement such extended cycles. In doing so, it has been realized that current technical specifications require 18-month surveillance test intervals for many of the refueling interval surveillances. Three C-E utilities have committed to 24-month cycles as of the writing of this paper, with two others seriously considering such extensions. All of these utilities have multiple units at their sites. To assist these utilities, the C-E Owners' Group has undertaken a study to justify the extension of these surveillance test intervals. Earlier work in support of surveillance interval extension looked at the impact of surveillances on (a) availability and (b) methods that might be used for the extension of surveillance intervals. It has been found possible to justify the extension of most surveillance test intervals to at least 24 months. Applying the present technical specification allowance of {plus minus}25% to these intervals provides sufficient operating flexibility to accommodate nominal 24-month fuel cycles. The problem areas encountered are those to which the {plus minus}25% allowance cannot be applied, such as to tube inspections. Even these do not preclude 24-month cycles but make the planning for a midcycle surveillance shutdown prudent.

• OSTI ID: 5227766
• Report Number(s): CONF-890833--
• Conference Information: Journal Name: Transactions of the American Nuclear Society, Supplement; (USA) Journal Volume: 59
• Country of Publication: United States
• Language: English

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