B11919, Informs That Four Zircaloy-clad Lead Test Assemblies Will Be Placed in Nonlimiting Core Locations & steady-state Peak LHGR Will Not Exceed 11 Kw/Ft for Cycle 14.Exemption from 10CFR50.46 & App K Should Remain Valid

Informs That Four Zircaloy-clad Lead Test Assemblies Will Be Placed in Nonlimiting Core Locations & steady-state Peak LHGR Will Not Exceed 11 Kw/Ft for Cycle 14.Exemption from 10CFR50.46 & App K Should Remain Valid

ML20138N954
Person / Time
Site:	Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png
Issue date:	12/13/1985
From:	Opeka J CONNECTICUT YANKEE ATOMIC POWER CO.
To:	Charemagne Grimes Office of Nuclear Reactor Regulation
References
B11919, NUDOCS 8512240222
Download: ML20138N954 (2)

Text

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e CONNECTICUT YANKEE ATOMIC POWER COMPANY B E R L I N, CONNECTICUT P.o. box 270 HARTFORD, CONNECTICUT 06141-0270 TELEPHONE cos-ess-sooo -

December 13, 1985 Docket No. 50-213 B11919 Director of Nuclear Reactor Regulation Attn: . Mr. Christopher I. Grimes, Director Integrated Safety Assessment Project Directorate U.S. Nuclear Regulatory Commission Washington, D.C. 20555

Reference:

W. A. Paulson letter to W. G. Counsil, dated October 2,1984,

Subject:

Exemption from 10CFR50.46 and Appendix K.

Gentlemen:

Haddam Neck Plant Zircaloy Clad Demonstration Assemblies Connecticut Yankee Atomic Power Company (CYAPCO) is evaluating the option of converting the existing stainless steel clad core at the Haddam Neck Plant to a zircaloy clad core in order to reduce the enrichmer.t of uranium required for a fuel cycle and the associated reduction in separative work units required. The Technical Specifications currently authorizes the use of four (4) zircaloy clad assemblies containing up to 400 Kg of Zircaloy-4.

The referenced letter transmitted an exemption from the requirements of 10CFR50.46 and Appendix K for the installation of up to four zircaloy clad lead test assemblies (LTAc in the Haddam Neck ccre at locations in which the calculated stewy-state peak linear heat generation rate (PLHGR) does not exceed 11 kW/f t. The exemption assumed the four LTAs would remain in the core for three ';el cycle

• starting with Cycle 13.

The purpose of tl.is le.nar is to inform you that the four LTAs will be placed in non-limiting core locations and, the steady-state PLHGR will not exceed l 11 kW/ft for Cycle 14. The nuclear analysis for Cycle 14 shows that the LTAs l could experience a transient PLHGR of 11.3 kW/ft at the bounding allowable I axial offset limit. The impact of the slightly higher PLHGR on the ECCS l performance evaluation for the large break LOCA has shown that substantial margin remains to the Appendix K peak cladding temperature limit of 2,2000F and peak locai clad oxidation percentage limit of 17% Additionally, the measured PLhGR for the I.TAs during Cycle 13 have been shown to be almost 2.0 kW/ft less than the ll.0/kw it allowed during steady-state operation. The l same relatioaship between the measured and allowable PLHGR for the LTAs is expected for Cycle 14.

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Based on the above evaluation,;CYAPCO concludes that:the exemption remains

. valid for the use of four LTAs in the Haddam Neck core during Cycle'14._- This 4

{ conclusion has been informally agreed to in recent discussions between the NRC m.. A 10CFR50.59 '- evaluation will' be' periormed and

- : Staff and D CYAPCO.

documented prior. to utilizing the four LTAs in Cycle 14 to ensure that applicable - 3" lacceptance criteria are fulillied.--

- i.CYAPCO ?;. recognizes : that ~ core-wide. : conversion ; to zirconium clad ! fuel -

6 necessitates compliance with Appendix K.;'If CYAPCO; elects to pursue this

~ alternative, the required . amendment request will be based uponfan Appendix K

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-;model for the Haddam Neck Plant, which must be reviewed and approved by the m F NRC prior to its ' utilization as part of the licensing basis for the plant.

lShould the' NR'C Staff express the view that a revision to the existing exemption

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- or a new exemption from the applicable portions of 10CFR50.46 and Appendix K '

may be necessary, please inform us promptly.

Very truly yours, CONNECTICUT YANKEE ATOMIC POWER COMPANY

< 3. F. Opek'a

f. &

-U Senior Vice President '

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