ML20082T482

Proposed Tech Spec Rev Re Use of H-451 Graphite in Fuel Rods.Significant Hazards Consideration Analysis Encl

ML20082T482
Person / Time
Site:	Fort Saint Vrain
Issue date:	12/02/1983
From:	PUBLIC SERVICE CO. OF COLORADO
To:
Shared Package
ML20082T428	List: ML20082T427 ML20082T447 ML20082T465 ML20082T482
References
NUDOCS 8312160031
Download: ML20082T482 (4)

Text

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e ATTACHMENT 4 PROPOSED REVISION t

i B322160031 8"1202 PDR ADOCK 05000267 P __ pg ,

_h.mh____- .-_.mm_ _-_a-_ .h_.._mmu_. _._mA._ 3 1.mm __ . .. _'_: m mr _M1 m_.m.- - E

. Fort St. Vrain #1 Technical Specifications Amendment #

Page 6.1-4 In addition to the reference fuel elements, eight test fuel elements are included in the reactor core. These eight test elements (FTEl-8) contain small quantities of test fuel particles that are in various ways different from the reference fuel The description of the test fuel elements is contained in Table 6.1'1. .

"ise' coated fuel particles -a're bonded together with a carbonaceous material to form fuel rods. The fuel rods are completely surrounded and contained by graphite which forms the structural part of the fuel element and, in addition to the carbon contained within the fuel rods, also serves as the sole moderator. The reference fuel elements are fabricated from H-327 needle coke (anisotropic) graphite, as described in the Fort St.

Vrain FSAR, Section 3.0. The test fuel elements are fabricated from H-451 near-isotropic graphite in anticipation of qualifying this material for future use in all reload fuel for the reactor.

l Beginning with core Segment 9 (Reload 3), H-451 near-isotopic graphite l is used in the fabrication of reload fuel elements in addition to or in place l of the previous reference H-327 needle coke (anisotropic) graphite.

Reflector Reflector elements above, below, and immediately adjacent to the side of the active core are hexagonal right prisms with ncminal dimensions of 14.2 inches across flats and 15.6, 23.4, or 31.2 inches high, as required.

The outer peripheral envelope of the reactor core reflector graphite contains boron to minimize the neutron flux leaving the relfsctor. The side reflector contains nominal 2.3 weight perc'ent boron stainless steel pins M_.-'--~___.___, _ - - - - - _ _.

. Fort St. Vrain #1

~ Technical Specifications Amendment #

Page 6.1-5 within .the spacer blocks. The middle layer of lower reflector elements, excluding the central element in each core region, contains 25 weight percent boronated graphite pellets enclosed in hastalloy-X cans. The top layer of reflector above the hexagonal colums contains 1 weight percent crused baronated graphite. The top layer of reflector above the permanent side reflector blocks contains 1 weight percent boronated graphite enclosed in steel cans.

Basis for Specification DF 6.1 The above specifications form the general design bases and criteria I

for the overall design features of the reactor core which were used to evaluate its general performance. Further details concerning these design features are given in Section 3.0 of the FSAR and the' Safety Analysis Report for Fort St. Vrain Reload 1 Test Elements FTE-1 through FTE-8, General Atomic Document GLP-5495, June 30, 1977.

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l ATTACHMENT 5 SIGNIFICANT HAZARDS' CONSIDERATIONS ANALYSIS A review of Chapter XIV of the Final Safety Analysis Report (FSAR) identified six postulated accident conditions which required 'more detailed examination for potential impact from the substitution of H-451 graphite in Segment 9 for the ' fuel element block material.

These accident conditions were discussed in this section.and no' requirement for additional analysis has, been identified. It is concluded that the worst case conditions previuusly defined for accident analyses, and found to be acceptable during the FSAR review, are not exceeded as a result of introducting H-451 graphite in Segment 9. This result is consistent with 'the conclusions of.

Attachments 1, 2, and 3. This design change presents no unreviewed safety questions, as defined in 10CFR50.59 Based on the above, operation of Fort St. Vrain in accordance with the proposed change will not (1) involve'a significant _ increase in

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the probability or consequences of an accident-previously _ evaluated, (2)_ create the possibility of a.new or different --kind of accident from any' accident previously evaluated, or (3) ' involve a significant

. reduction in a margin of. safety. It is, therefore, apparent that no:

significant hazards considerations are involved.

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