ML20196E686

Application for Amend to License DPR-21,revising Tech Specs to Reflect Implementation of Mods Re Degraded Grid Protection for Class 1E Power Sys.Fee Paid

ML20196E686
Person / Time
Site:	Millstone
Issue date:	12/02/1988
From:	Mroczka E, Sears C NORTHEAST NUCLEAR ENERGY CO., NORTHEAST UTILITIES
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
Shared Package
ML20196E692	List: B13089, Proposed Tech Specs,Providing for New Limiting Conditions for Operation,Surveillance Requirements & Nominal Setpoints for New 4160 Volt Bus Undervoltage/Timing Relay Input Circuits & loss-of-normal Power Actuation Circuits Mods ML20196E686
References
B13089, GL-83-80, NUDOCS 8812120063
Download: ML20196E686 (6)

Text

e-NORTHEAST UTILITIES cenem Omces seioen street. eeron. Connect' cut HA TFORD CONNECTICUT 06141-0270 k L IJ CN,N.]. 'g*f (203) 665-5000 December 2, 1988 Docket No. 50-245 B13089 Re: 10CFR50.90 U.S. Nuclear Regulatory Comission Attention: Document Control Desk Washington, DC 20555 Gentlemen:

Millstone Nuclear Power Station, Unit No. 1 Proposed Revision to Technical Specifications Undervoltaae and LNP Protection Modification Pursuant to 10CFR50.90, Northeast Nuclear Energy Company (NNECO) hereby proposes to amend its Operating License, No. DPR-21, by incorporating the changes identified in Attachment 1 into the Technical Specifications of Millstone Unit No. 1.

The proposed changes will reflect the implementation of the modifications related to degraded grid protection for Class IE power systems at Millstone Unit No. 1, which are scheduled to be completed during the 1989 refueling outage. A sumary of the planned in a letter dated August 15,1988.gifications was provided to the NRC Staff Backaround NNEC0 has evaluated Millstone Unit No. l's power supply system against 10CFR50 Appendix A, General Design Criteria (GDC) 17 with regard to the ability of the plant to cope with a degraded voltage condition under Topics 1.23 and 1.25 of the Iggrated Safety Assessment Program (ISAP). In a letter dated May 22, 1987, NNEC0 provided a sumary of our efforts to incorporate a loss of voltage and degraded voltage detection and actuation scheme to meet the intent of NRC Branch Technical Position (BTP) PSB-1, "Adequacy of Station Electric Distribution System Voltages." A description of the existing undervoltage protection scheme and a comparison of it with the criteria of BTP PSB-1 was included. As stated in our August 15, 1988 letter, the modifications will be completed during the 1989 refueling outage, which is currently scheduled to begin around April 1. The undervoltage (degraded and loss-of-voltage)

(1) E. J. Mroczka letter to U.S. Nuclear Regulatory Comission, "Degraded Grid Protection for Class IE Power Systems," dated August 15, 1988.

(2) E. J. Mroczka letter to U.S. Nuclear Regulatory Comission, "Degraded Grid Protection for Class IE Power Systems," dated May 22, 1987. /

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U.S. Nuclear Regulatory Commission B13089/Page 2 December 2, 19f.,)

protection will be relocated to the Class IE buses and the automatic reinstatement of the load shed feature will be provided. This modification will upgrade Millstone Unit No. l's bus protection to the requirements of IEEE 279-1971 and meet the intent of BTP-PSB-1.

NNECO submitted a related license amendment request on July 16,1980.(3) This amendment request supersedes our previous request.

The new equipment was installed during the 1984 refueling outage and the outputs were tied to alarm circuits to monitor for any spurious operation.

The actual trip circuits are to be tied in during the 1989 refueling outage.

The revised design does not split the output load shed and loss-of-normal power (LNP) logic, thus alleviating concerns with the asymmetrical bus config-uration of the previously proposed design. Instead, redundant LNP channels will be provided to ensure the adequacy of the power supply to safety related equipment. Automatic reinstatement of the load shed feature is provided for with individual bus voltage relaying that will load shed the respective bus should voltage be lost. In addition, a reactor scram signal will be generated should 4160 volt Bus 14A,148,14C, or 14D become deenergized, in order to

<ninimize the transient expected upon the loss of a primary bus.

The proposed changes to the Technical Specifications provide for new limiting Conditions for Operation (LCOs), Surveillance Requirements, and nominal setpoints for the new 4160 volt bus undervoltage/ timing relay input circuits to be installed during the 1989 refueling outage. In addition, the Technical Specifications for the bus voltage permissive and the LNP actuation circuits are being modified to provide additional detail and clarification. In general, the proposed changes provide more stringent requirements and are conservative in nature.

The NRC BTP PSB-1 states that the Technical Specifications should include the following:

o LCOs o Surveillance Requirements o Trip setpoints with minimum and maximum limits o Test requirement to demonstrate the operability of the automatic bypass and reinstatement features at least once per eighteen months during shutdown.

As stated above, appropriate LCOs and Surveillance Requirements are being proposed to be included in the Technical Specifications. The actual trip setpoints will be left out of the Technical Specifications. These setpoints will be checked each refueling outage by electrical test personnel and will be addressed in plant surveillance procedures.

(3) W. G. Counsil letter to D. M. Crutchfield, dated July 16, 1980.

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U.S. Nuclear Regulatory Commission B13089/Page 3 December 2, 1988 Testing to demonstrate the operability of the automatic bypass and reinstate-ment features each outage will not be conducted, to eliminate severe testing cf the Gas Turbine and Diesel Generator systems. This test will be done on a one-time basis prior to start-up from the 1989 refueling outage. NRC Generic Letter No. 83-80 deletes this requirement from the BWR Standard Technical Specifications.

Descriotion of Chanaes The following proposed Technical Specification changes are editorial in nature.

A. Table 3.2.2. Instrumentation that Initiates and Controls the Emeraency Core Coolina System. Page 3/4 2-5 The requirement for Power Available on Emergency Buses undervoltage (VV) relays will be relocated to Sections 3.9, 4.9 and Table 3.9.1, which are discussed separately.

B. Igble 3.2.2. Paae 3/4 2-6 The requirement for loss-of Normal Power Relays will be relocated and clarified in Sections 3.9. A, 4.9. A, 3.9.B 4.9.B, and Table 3.9.1 which are discussed separately.

C. Table 4.2.1. Minimum Test and Calibration Freauency for Core Coolina Instrumentation Rod Blocks and Isolations. Paaes 3/4 2-9 and 3/4 2-10 The requirements for the Loss-of-Normal Power Relays and the Power Available Relays will be relocated to Table 3.9.1.

D. Section 3.9. A.4. Auxiliary Electrical System. Limitina Conditions for Ooeration. Paae 3/4 9-1 The requirement to have 4160 volt buses 5 and 6 energized will be changed to buses 14A,14C,14E, and 14F to reflect actual Millstone Unit No. I designations and specify the buses required for the feedwater coolant injection system (FWCI).

! E. Section 4.9. A.l.b and 4.9. A.2.b. Auxiliary Electrical System. Surveil-lance Reauirements. Paae 3/4 9-2 A sentence will be added to each of these paragraphs to clarify the requirement to test the sequence of bus deenergization, load shedding, voltage restoration, and load sequencing during the diesel and gas turbine generator tests performed during each refueling outage.

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U.S. Nuclear Regulatory Commission B13089/Page 4 December 2, 1988 F. Bases Section 3.9. A and 3.9.B. Auxiliary Electrical System Bases. Paae B f 3/4 9-1 ,

A statement will be added to each of these sections to clarify that the r voltage and loss-of-normal power relaying are required for successful operation of the diesel and gas turbine generators. -

G. Section 4.9.A. Pace 3/4 9-2 ,

Section 4.9. A.3 will be added which specifies the same surveillance  !

requirements as will be deleted from Table 4.2.1. In addition, this section and Table 3.9.1 will clearly specify which relays are required to be tested.

The following changes have a potential safety impact, t A. Bases Section 3.1. Reactor Protection System. Pace B 3/4 1-4 A paragraph will be inserted to provide the basis for providing an automatic scram on a loss of power to buses 14A,14B,14C, or 140 i.e., ,

minimizes the expected transient in the event of a loss of one of(these i buses). The inclusion of the undervoltage scram signal is a safety l enhancement, which is not required for either the existing design or the new design. This scram function is independent of the undervoltage design changes. This is being implemented strictly as a conservative measure, with no adverse effects. Since we will, at this time, continue to be bounded by our existing design basis analyses, an t.C0 for this scram function will not be added.

B. Eqrtion 3.9.A. Auxiliary Electrical System. Limitina Condition for Ooeration. Paae 3/4 9-1  ;

A new paragraph (3.9.A.5) will be added which requires that all voltage and loss-of-normal power relaying be operable as specified by Table  :

3.9.1. The equipment was always required, but not explicitly stated in  !

! the Technical Specifications.

l i C. SElion 3.9.B. Auxiliary Electrical System. Limitina Condition for

Opert. tion. Paae 3/4 9-3 i A new saction 3.9.8.5 will be added which references Table 3.9.1 for the appropriate action statements if the voltage or loss-of normal power >

relaying is made or found inoperable. '

1 D. Table 3.9.1. Voltaae & Loss-of-Normal Powar Relayina. Paae 3/4 9 2a. b.

and c This table will added to specify the minimum number of relays required, l surveillance requirements for the relays, and action statements to be >

l taken if the relaying is made or found inoperable.

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e U.S. Nuclear Regulatory Commission B13089/Page 5 December 2, 1988 Sionificant Hazards Consideration In accordance with 10CFR50.92, NNECO has aviewed the attached proposed changes and has concluded that they do not invube a significant hazards consideration. The proposed changes do not involve 3 significant hazards L consideration because they would not.

1. Involve a significant increase in the prob =bility or consequences of an accident previously analyzed. The impact of the cht.nge on design basis accidents (DBAs) which assume loss of off-site power has been reviewed and has been determined to be unaffected by the change. The proposed changes, in general, provide for more conservatism in that the opera-bility requirements for the on-site emergency buses and their associated cor. trol circuits are more restrictive than the existing requirements.

These changes to the Technical Specifications do not impact the failure probability of the associated electrical system, rather they increase the probability that a train of emergency electrical power is available following an accident. The probability of occurrence 3r the consequences of the DBAs are unchanged.

2. Create the possibility of a new or different kind of accident from any previously evaluated. There are no new failure modes associated with the proposed changes since they involve more restrictive requirements on the operability of the electrical power systems. No new accident is created because the same equipment is assumed to perform in the same manner as before.

3. Involve a significant reduction in a margir of safety. The protective boundaries are not impacted because the consequences of the DBA are not affected. Since the protective boundaries are not affected, the safety

, limits are also not affected. The proposed change maintains the basis of

the Technical Specifications in assuring electrical power operability.

The existing 345 kV LNP sensing inputs are not in the Technical Specifi-cations. Technical Specification for the new 4160 volt bus undervoltage/ timing relay input circuits will be added. The existing Technical Specification for the bus voltage permissive and the LNP l actuation circuits are being modified to provide additional detail and t clarification.

The Commission has provided guidance concerning the applications of standards

set forth in 10CFR50.92 by providing certain examples (March 6, 1986, EB 7751)

of amendments that are considered not likely to involve a significant hazards

! consideration. The changes proposed herein most closely resemble example (ii)

I which constitutes an additional limitation or control not presently included in the Technical Specifications. Since the proposed changes provide for more

! restrictive operability requirements and provide new requirements for testing and calibrating the undervoltage setpoints, the proposed changes result in added assurance that the electrical power system will be available. There-( fore, the proposed changes would not involve a significant hazards considera-

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tion.

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U.S. Nuclear Regulatory Comission B13089/Page 6 December 2, 1988 The Millstone Unit No.1 Nuclear Review Board has reviewed and approved the attached proposed revisions and has concurred with the above determinations.

We remain prepared to meet with the NRC Staff to further discuss this issue.

We would like to bring to the Staff's attention that these proposed c.hanges are rJquired 3rior to start-up from the upcoming refueling outage. As such, we respectful 9y request NRC review and approval commensurate with this sched-ule.

In accordance with 10CFR50.91(b), NNECO will provide the State of Connecticut with a copy of this proposed amendment.

Pursuant to the requirements of 10CFR170.12(c), enclosed with this amendment is the application fee of $150.

Very truly yours, NORTHEAST NUCLEAi'. ENERGY COMPANY

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• E. J. Mroczka Senior Vice President LW/L By: C. F. Sears Vice President Enclosure cc: Mr. Kevin McCarthy Director, Radiation Control Unit Department of Environmental Protection Hartford, CT 06116 W. T. Russell, Region ! Administrator M. L. Boyle, NRC Project Manager, Millstone Unit No. 1 W. J. Rayuond, Senior Resident Inspector, Millstone Unit Nos.1, 2, and 3 STATE OF CONNECTICUT ss. Berlin COUNTY OF HARTFORD Then personally appeared before me, C. F. Scars, who being duly sworn, did state that he is Vice President of i. irtheast Nuclear Energy Company, a Licensee herein, that he is authorized to exe.ute and file the foregoing inforrution in the name and on behalf of the Licensee herein, and that the

statements contained in said information are true and correct to the best of

his knowledge and belief. -

Mbw bv >e[k J

Notary Pub ic My Cee::':n C9X t f.'rc 31,1.93