ML20082B144

Application for Amend to License NPF-49,revising TS 3.10.5 to Allow More than One Control Bank to Be Fully Withdrawn from Core Simultaneously for Rod Drop Time Response Testing

ML20082B144
Person / Time
Site:	Millstone
Issue date:	03/29/1995
From:	Opeka J NORTHEAST NUCLEAR ENERGY CO., NORTHEAST UTILITIES
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20082B145	List: B15159, Proposed Tech Spec 3.10.5,allowing More than One Control Bank to Be Fully Withdrawn from Core Simultaneously for Rod Drop Time Response Testing ML20082B144
References
B15159, NUDOCS 9504050031
Download: ML20082B144 (6)

Text

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'"Y Northeast i 7 sciaen st=n sers Cr 06037 j g Utilities System 8

Northeut venue. senw cmoi,aoy I P.O. Box 270 i

. Ilartford, CT 061410270 (203) 665-5000 i

1 March 29, 1995  !

Docket No. 50-423 B15159 j Re: 10CFR50.90 U.S.. Nuclear Regulatory Commission Attention: Document Control Desk ,

Washington, DC 20555 Millstone Nuclear Power' Station, Unit No. 3 Proposed Revision to Technical Specifications '

Special Test Exceptions - Inoperable Rod Position Indication System Durina Rod Dron Time Testina Introduction i

Pursuant to 10CFR50.90, Northeast Nuclear Energy Company (NNECO)'  !'

hereby proposes to amend its Operating License, NPF-49, by incorporating changes identified in Attachments 1 and 2 into the i Technical Specifications of Millstone Unit No. 3. The purpose of ,

the proposed changes ' to Technical Specification 3.10.5 is to ,

allow more than one control bank to be fully withdrawn from the core simultaneously for rod drop time response testing. During [

rod drop time testing, under this proposal it will be required

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that the shutdown margin requirements be met without crediting the withdrawn control rods. This requirement is necessary to provide a margin of safety in K,, since the reactivity state of t the new core will not have been evaluated' prior to the rod drop time tests.

Descrintion of the Proposed Chances NNECO will be installing an improved rod drop computer during the upcoming refueling outage in April 1995. This new computer has the capability to measure the time. responses er all rods

• simultaneously. The proposed technical specification changes, described below, will decrease test time and the impact of rod drop time testing on critical path activities during the ,

refueling outages.  ;

NNECO proposes to revise the Millstone Unit No. 3 Technical  !

Specification Section 3.10.5 which will allow more than one control bank to be fully withdrawn from the core simultaneously for rod drop time response testing. Specifically, NNECO proposes i

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,B15159/Page 2 March 29, 1995 to delete, (1} the limiting condition for operation (LCO) 3.10.5.a and (2) a reference to the full length shutdown rods from LCO 3.10.5. However, NNECO is proposing to add a requirement which is necessary to provide a margin of safety in Q , since the reactivity state of the new core will not have been evaluated prior to the rod drop time test. Specifically, a requirement to LCO 3.10.5 is being added to state: "The SHUTDOWN l MARGIN requirement of Section 3.1.1.1.2 shall be met without i credit for withdrawn control rods." The footnote at the bottom of Page 3/4 10-6 is being revised to reflect changes to LCO 3.10.5. In addition, NNECO proposes to revise Bases Section 3/4.10.5, Position Indication System - Shutdown, to reflect the changes proposed to Specification 3.10.5. Also, a typographical error in Bases, Sections 3/4.1.1.1 and 3/4.1.1.2, Shutdown Margin, has been corrected.

Additionally, it is noted that the proposed changes to Specification 3.10.5 maintain the requirement to observe the shutdown margin requirement of Specification 3.1.1.1.2 without crediting withdrawn rods. This has the effect of changing the required subcritical state of the reactor system from Q < .99 to a much lower value crediting boron only. In addition, during the conduct of the test with rods withdrawn, the additional available negative reactivity from the rods upon receipt of a reactor trip signal increases the available shutdown margin appreciably.

Further, testing rod drop time with a greater number of banks at one time is more prototypic of expected conditions and improves confidence in the applicability of the results to the safety analysis. These several factors each have the desirable effect '

of substantially increasing the margin of safety.

safety Assessment The proposed change to Technical Specification 3.10.5 will allow more than one control and shutdown bank to be fully withdrawn from the core simultaneously for rod drop time response testing.

During this testing, it will be required that the shutdown margin requirement be met without crediting the withdrawn control rods.

This test is performed in Modes 3, 4, or 5.

Currently, the technical specifications allow the rod position indication system to be disabled for each control bank while performing this test. The proposed change allows the rod position indication to be removed simultaneously from all the control and shutdown banks while performing this test. The rod position indication system is not a safety system credited in the accident analyses. Therefore, allowing more than one bank to have its indication removed during the test does not degrade any

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U.S. Nuclear Regulatory Commission

,B15159/Page 3

-March 29, 1995 safety system. In addition, the LCO for Technical Specification 3.1.3.3 (rod position indication operability) is met since the  !

rod drop test is initiated by opening the reactor trip breakers.

There are two changes to the Bases section of the Technical  !

Specifications. The first change is to Bases 3/4.10.5 and adds a  :

description of the proposed change. The second change is to l Bases 3/4.1.1.1 and corrects a Specification reference, whereby  !

the shutdown margin for Modes 3, 4, and 5 is properly referenced  !

to 3/4.1.1.1.2 not 3/4.1.1.2. Both of these changes are editorial in nature and have no impact on safety. l The design basis accident of primary concern during Modes 3, 4, '

and 5 is the boron dilution accident. In this accident analysis, a minimum shutdown margin, as defined in Specification 3/4.1.1.1.2, is required to allow the operator 15 minutes from the initiation of the shutdown margin monitor alarm to total loss of shutdown margin. For each reload the Nuclear Design Report will contain minimum boron concentrations required to meet the i shutdown margin provided in technical specifications during the rod drop test. Minimum boron concentrations will be provided for  ;

different combinations of control and shutdown banks withdrawn.

Since shutdown margin of 4 of less than or equal to .95 will always be maintained during the test, the assumptions in the boron dilution accident are unchanged, and there is no impact on ,

the consequences of the accident analysis. )

Other accidents that are postulated during shutdown, that could be impacted by this change, are rod ejection'and uncontrolled rod withdrawal from subcritical. The limiting case for these accidents is all rods in (ARI) because core power. peaking is more severe. This limiting case bounds the configuration established during the rod drop test as allowed by this proposed change.

Therefore, the assumptions in these accidents remain unchanged, and there is no impact on the consequences of the accident .

analysis. l

[ sianificant Hasards Consideration Determination l In accordance with 10CFR50.92, NNECO has reviewed the proposed changes and has concluded that they do not involve a significant hazards consideration (SHC). The basis for this conclusion is l that the three criteria of 10CFR50.92(c) are not compromised.

l The proposed changes do not involve an SHC because the changes would not: '

1. Involve a significant increase in the probability or consequences of an accident previously evaluated. j I

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U.S.. Nuclear Regulatory Commission  ;

~B15159/Page 4

' March 29, 1995' The' proposed changesL . cannot initiate an event since ~ the i plant will be maintained shutdown at all-times. Thus, there is no : increase in the probability of occurrence of an '

accident previously evaluated.

The proposed changes do not degrade the performance of ' any safety' system nor do they alter any assumptions made in the accident analyses. Currently, the technical specifications allow the rod position' indication system to be. disabled for i sach control bank while performing this test. .In addition, i this system is not a safety system credited in-the accident analyses. Therefore, allowing more than one bank to have its indication removed during the test does not degrade any i safety system. Since the shutdown margin will be maintained j without crediting these rods, there . is no change to the assumptions made in-the accident analyses. Thus, there is no increase -in the consequences of ~ an accident previously >

evaluated.

2. Create the possibility of a new or different kind of accident from any previously analyzed. l The proposed changes do not position the control rods-into any new configurations or sequence not previously analyzed.

Ejected rod worths are evaluated for ARI-1 (all rods in with the most reactive rod out) and, therefore, bound the test configuration. In addition, the reactivity state of the i system is maintained shut down by the margin required in Technical Specification 3.1.1.1.2 without crediting the control rods. Therefore,.there is no possibility-of a new or different type of accident than previously analyzed.

3. Involve a significant reduction in the margin of safety.

The proposed changes do not impact any of the physical protective boundaries, safety systems, or operating-conditions. The plant will be maintained shut down without crediting the control rods. The accident analyses ~ is not impacted and, therefore, there is no reduction in the margin of safety.

Moreover, the Commission has provided guidance concerning the l application of standards in 10CFR50.92 .by providing certain l

examples (March 6, 1987, 51FR7751) of amendments that are considered not likely to involve an SHC. The proposed changes  ;

are not enveloped by any of the examples. However, NNECO has concluded that the proposed changes do not negatively impact'the public health'or safety, nor do they involve an SHC.

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U.S. Nuclear Regulatory Commission

,B15159/Page 5 March 29, 1995 Environmental Considerations NNECO has reviewed the proposed license amendment against the criteria of 10CFR51.22 for environmental considerations. The proposed changes do not involve an SHC, do not increase the types and amounts of effluents that may be released offsise, nor significantly increase individual or cumulative occupational radiation exposures. Based on the foregoing, NNECO concludes that the proposed changes meet the criteria delineated in 10CFR51. 22 (c) (9) for a categorical exclusion from the requirements for an environmental impact statement.

Nuclear Safety Assessment Board Review The Nuclear Safety Assessment Board has reviewed and approved this proposed amendment and concurs with the above determination.

State Notification In accordance with 10CFR50.91(b) , we are providing the State of Connecticut with a copy of this proposed amendment via facsimile to ensure their awareness of this request.

Schedule for NRC ADDroVal Regarding our proposed schedule for this amendment, we request issuance at your earliest convenience, with the amendment effective as of the date of issuance, to be implemented within 60 days of issuance.

If you should have any questions, please contact Mr. R. G. Joshi at (203) 440-2080.

Very truly yours, NORTHEAST NUCLEAR ENERGY COMPANY he. -

J. F.u peka Q Executive Vice President cc: See Page 6 a

e U.S. Nuclear Regulatory Commission

.B15159/P. age 6 March 29, 1995 cc: T. T. Martin, Region I Administrator V. L. Rooney, NRC Project Manager, Millstone Unit No. 3 P. D. Swetland, Senior Resident Inspector, Millstone Unit Nos. 1, 2, and 3 Mr. Kevin T.A. McCarthy, Director Monitoring and Radiation Division Department of Environmental Protection 79 Elm Street P.O. Box 5066 Hartford, CT 06102-5066 Subscribed and sworn to before me this M 7// day of Narod , 1995 h/ Arts Y Date Commission Expires: /d!7/ 7

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