B13185, Documents Util Rationale in Not Assigning Senior Reactor Operator to Be Present During Replacement of in-core Detectors.Util Proposes to Submit Proposed Change to Definition Section of Tech Specs,For NRC Approval

Documents Util Rationale in Not Assigning Senior Reactor Operator to Be Present During Replacement of in-core Detectors.Util Proposes to Submit Proposed Change to Definition Section of Tech Specs,For NRC Approval

ML20248F344
Person / Time
Site:	Millstone
Issue date:	04/03/1989
From:	Mroczka E, Sears C NORTHEAST NUCLEAR ENERGY CO., NORTHEAST UTILITIES
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
B13185, NUDOCS 8904130034
Download: ML20248F344 (3)

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NORTHEAST E8TILITIES ' oenerai Orrices . seiden street seriin. Connecticut I t s5a " P.O. BOX 270 HARTFORD, CONNECTICUT 06141-0270 k '. J Z wm:1Q' [ h". c"oww.

ucas (203) 665-5000 April 3, 1989 Docket No. 50-336' B13185 Re: T.S. 6.2.2.e U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555 Gentlemen: l Millstone Nuclear Power Station, Unit No. 2 i Replacement of In-Core Detectors Millstone Unit No. 2 is currently in a refueling outage. One of the tasks performed routinely at each refueling outage is the replacement of a portion (approximately half) of the in-core instrumentation detectors. The procedures for this task are well established and were being implemented by plant person-nel to change out 23 of the 46 in-core detectors. During the performance of this task, : > was noted that a Senior Reactor Operator (SR0) was not present in apparent conflict with the requirements of Technical Specification 6.2.2.e.

The purpose of this letter is to document Northeast Nuclear Energy Company's (NNEC0) rationale in not assigning an SR0 to be present during the replacement of the in-core detectors.

Technical Specification 6.2.2.e states: "ALL CORE ALTERATIONS after the initial fuel. loading shall be directly supervised by either a licensed Senior ,

Reactor Operator or Senior Reactor Operator Limited to Fuel Handling who has no other concurrent responsibilities during this operation."

Technical Specification 1.12 defines Core Alteration as "the movement or manipulation of any component within the reactor pressure vessel with the vessel head removed and fuel in the vessel." This definition is consistent with the CE Standard Technical Specifications.

It has been and remains NNEC0's interpretation that the replacement of in-core instrumentation (ICI), as performed according to procedure IC2419A, does not constitute the intent of a " Core Alteration," and therefore does not require c- the presence of an SR0. It is our understanding, based upon conversations with personnel from other facilities, that this interpretation is virtually identical to that of other PWR's across the country.

NNEC0 understands a core alteration to be an activity that could in some way affect the reactivity of the core consistent with the safety intent of this specification. Not only does the replacement of in-core detectors have a negligible effect on core reactivity, but the activity does not pose a threat to. damaging the fuel which could result in a radioactive release. The Millstone Unit No. 2 Plant Operations Review Committee (PORC) recently confirmed the continued acceptability of this interpretation. gl 8904130034 890403 i g PDR ADOCK 05000336 P PDC g i l

U.S. Nuclear Regulatory Commission B13I85/Page 2 April 3, 1989 Specifically:

I (I) The Upper Guide Structure (UGS) was installed in the reactor vessel, '

causing the fuel assembly upper and lower end fittings to be fixed in place. Therefore, the fuel assemblies in the core could not be moved without first removing the UGS, and thus cannot be affected by the ICI removal and installation. ]

1' (2) The operation of removing an ICI is closely controlled by IC 2419A, ICI Replacement - Installation Procedure, with respect to the loads that are applied to the ICI. In addition, the rigging that is used to remove the ICI is light enough such that it would fail long before it could transmit enough force to move the UGS. Therefore, the UGS cannot be moved during the ICI installation and removal process.

(3) The ICI's and ICI thimble tubes are inserted into the center guide tube of their respective fuel assemblies during the installation of ,

the UGS. Since the operation of installing and removing an ICI is i closely controlled by procedure IC 2419A with respect to the loads that are applied to the ICI, and the installation and removal of the ICI plate with the ICI thimble tubes are closely controlled by their respective procedures (MP 2704F and MP 2704J), the potential for l damaging a fuel assembly during ICI installation and removal is

, negligible.

1 f (4) The CEA's were uncoupled and the CEA Extension Shaft Protective l Sleeves were installed during the ICI installation and removal. The CEA Extension Shaft Protective Sleeves protect the CEA Extension Shafts from potential damage caused by raising and lowering the ICI plate. Since the CEA's were uncoupled and the CEA Extension Shaft Protective Sleeves were installed, the movement of the ICI plate cannot inadvertently withdraw any CEA's from the core.

! (5) The reactivity effects caused by the insertion and removal of the ICI and ICI thimble tubes into the core are negligible. The ICI thimble tubes are made of zircaloy, and their removal or insertion will have an insignificant effect on the core reactivity.

Therefore, the movement of the ICI plate and removal and installation of ICI's will have no noticeable positive reactivity addition to the core.

(6) The above described evolutions have been successfully carried out for many years at Millstone Unit No. 2 without incident, further demonstrating the acceptability of our approach.

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U.S. Nuclear Regulatory Commission B13185/Page 3

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April 3, 1989 Further, NNEC0's interpretation has been employed previously, such as during the 1988; refueling outage, with the cognizance of resident inspector personnel. We readily acknowledge that the wording of Technical Specification definition 1.12 invites multiple interpretations. The industry has recognized the inconsistency in the interpretation of the definition for " Core Alterations" and is proposing a new definition that more clearly states the overall intent.

To remedy this situation, and to avoid confusion during forthcoming outages, NNEC0 proposes to submit for Staff approval in the near future a proposed change to the " Definitions" section of the Technical Specifications which will clarify the definition of " CORE ALTERATIONS." Our proposed definition is expected to be consistent with the proposed Combustion Engineering Owners Group - Revised Standard Technical Specification (CEOG RSTS) definition of

" Core Alteration." With the issuance of the forthcoming amendment request, there will be improved clarity as to what constitutes a core alteration. With respect to the 1989 refueling outage evolutions, NNEC0 believes that the intent of the Technical Specification and basis has been mainhined.

Please do not hesitate to contact my staff if you have any questions. 4 Very truly yours, NORTHEAST NUCLEAR ENERGY COMPANY E D M nc ,

E. J. Mroczka N Senior Vice President h

By: C. F. Sears Vice President cc: W. T. Russell, Region I Administrator G. S. Vissing, NRC Project Manager, Millstone Unit No. 2 W. J. Raymond, Senior Resident Inspector, Millstone Unit Nos. 1, 2, and 3 P. Habighorst, Resident Inspector, Millstone Unit No. 2 t1 _ - _ . _ _ - - _ - - - - - - _ - - -