BECO-89-136, Application for Amend to License DPR-35,revising Tech Spec Section 3/4.9 to Incorporate Reactor Protection Sys Electrical Protection Assemblies

Application for Amend to License DPR-35,revising Tech Spec Section 3/4.9 to Incorporate Reactor Protection Sys Electrical Protection Assemblies

ML20247K394
Person / Time
Site:	Pilgrim
Issue date:	09/11/1989
From:	Bird R BOSTON EDISON CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20247K399	List: BECO-89-136, Application for Amend to License DPR-35,revising Tech Spec Section 3/4.9 to Incorporate Reactor Protection Sys Electrical Protection Assemblies ML20247K408
References
BECO-89-136, TAC-62793, NUDOCS 8909210147
Download: ML20247K394 (6)

Text

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10CFR50.90 y

BOSTONEDISON j

Pilgrim Nuclear Power station Rock y Hill Road Plymouth. Massachusetts 02360 Ralph G. Bird BECo 89- 136 Senior Vice President - Nuclear Septecber 11, 1989 U.S. Nuclear Regulatory Commission Document Control Desk Hashington, DC 20555 License DPR-35 Docket 50-293 PROPOSED TECHNICAL SPECIFICATION CHANGE TO SECTION 3/4.9: INCORPORATION OF REACTOR PROTECTION SYSTEM ELECTRICAL PROTECTION ASSEMBLIES (TAC 62793)

, Boston Edison Company proposes the attached changes adding Sections 3.9.A.7 and 4.9.A.4 to Section 3/4.9, " Auxiliary Electrical System", of the Pilgrim Nuclear Power Station Technical Specifications in accordance with 10CFR50.90. The proposed changes add Limiting Conditions for Operation and Surveillance Requirements reflecting the installation of Electrical Protection Assemblies (EPAs) to the Reactor Protection System power supplies at Pilgrim. This proposed change is in accordance with the NRC existing model technical specifications for EPAs. The change was also compared to NEDC-31681, " Improved BWR Technical Specifications" for Boiling Water Reactors (BWR)/4 that is currently under review but not approved by the NRC.

The requested change is described in Attachment A ant! the revised Technical Specification pages are in Attachment B.

d-R. G. Bird PMK/jcp/3223 Attachments 1 Signed Original and 37 Copies cc: See next page Commonwealth of Massachusetts)

County of Plymouth )

Then personally appeared before me, Ralph G. Bird, who being duly sworn, did state that he is Senior Vice President - Nuclear of Boston Edison Company and that he is duly authorized to execute and file the submittal contained herein in the name and on behalf of Boston Edison Company and that the statements in said submittal are true to the best of his knowledge and belief.

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.. September 11.-1989 U. S. Nuclear Regulatory Commission Page-Two-4 j

cc: Mr D. Mcdonald, Project Manager Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation i Mail-Stop: 14D1 l

~U. S. Nuclear' Regulatory Commission 1 1 White Flint North i 11555 Rockville Pike Rockville, MD 02852 U. S. Nuclear Regulatory Commission Region I 475 Allendale Road King of Prussia, PA 19406 Senior NRC Resident Inspector Pilgrim Nuclear Power Station i

Mr. Robert M. Hallisey,. Director Radiation Control Program Massachusetts Department of Public Health 150 Tremont Street, 2nd Floor Boston, MA' 02111 1

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. ATTACHMENT A Proposed Chanae Technical Specification section 3/4.9 is being revised by the addition of 1 sections 3.9.A.7, 3.9.A.7.a. 3.9.A.7.b and sections 4.9.A.4.a and 4.9.A.4.b.

Bases for section 3/4.9 are changed to reflect the proposed changes. Text that is currently on page 196 is moved to the top of page 197, but is  ;

textually unchanged. Details of the change are indicated by change bars in the margins of the modified Technical Specification pages of Attachment B of this letter. j Reason for Changg The proposed change is made to reflect the installation of Electrical Protection Assemblies (EPAs) on the Reactor Protection System (RPS) at Pilgrim

. Station.

The RPS-EPAs are provided to isolate the RPS power bus from the non-essential MG set or alternate power source in the event of overvoltage, undervoltage or underfrequency, thereby protecting the loads connected to the RPS bus from under/over voltage and underfrequency conditions.

If the RPS-EPAs are' operational, a fault downstream of them results in a low voltage condition at the RPS bus, and the EPAs will trip. An undervoltage or underfrequency condition, depending upon the deviation from the nominal, can potentially cause damage to the scram solenoids and other Class 1E devices.

For example. if a low voltage condition persists for an extended period of time.at the scram solenoids, the solenoids can chatter and potentially lose pneumatic control capability, resulting in loss of primary scram action.

In the event of the overvoltage condition, certain RPS equipment (logic relays and scram solenoids) may experience higher voltage than normal. If this situation persists for a reasonably long duration, it may cause equipment degradation.

The Pilgrim RPS-EPA modification was accepted by the NRC in a letter to Boston Edison dated July 28, 1982.

Safety Evaluation and Determination of No Significant Hazards The Code of Federal Regulations, 10CFR50.91 eequires that at the time a licensee requests an amendment, the licensee est provide to the Commission its analysis, using the standards in 10CFR50.92, of no significant hazards consideration. Therefore, in accordance with 10CFR50.91 and 10CFR50.92 the following analysis has been performed.

1. The operation of Pilgrim Station in accordance with the proposed amendment does not involve a significant increase in the probability or consequence of any accident previously evaluated.

A modification to Pilgrim installed redundant Class lE EPAs between the non-Class 1E RPS power supplies and the Class 1E RPS power supplies.

These EPAs consist of a contactor that is opened by (1) an overvoltage greater than or equal to 132 volts, (2) an undervoltage less than or equal to 108 volts, or (3) an underfrequency less than or equal to 57Hz.

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The cabinets and conduits for the EPAs are located in a seismic Category 1-structure providing protection from the effects.of tornadoes, tornado missiles, and external floods. The components of each monitoring system c are also seismically qualified for Class lE application as required by ~

General Design Criterion (GDC) 2.

There are two physically independent and fully redundant circuit interrupters provided for each RPS bus, including the alternate supply, complying.with GDC 21 requirements. This redundancy provides single failure protection in case one EPA does not function properly, and also 1 provides sufficient reliability to ensure the RPS performs its intended  ;

safety, function. i The Pilgrim Nuclear Power Station (PNPS) Final Safety Analysis Report (FSAR)-Section 7.2 states that the power to each of the two reactor protection trip systems is supplied, via a separate bus, by its own high-inertia, a-c motor generator set. The inertia is provided by a high inertial flywheel. The-inertia is sufficient to maintain voltage and frequency within 5% of rated values and a frequency of not less than 55 Hz for at least 1.0 second following total loss of power to the MG set. The selection of the proposed EPA trip level settings at 10% of nominal voltage and -5% of nominal frequency allows the MG set to function within its intended and designed time, voltage and frequency range before the EPAs trip. These settings support the design and function of the high-inertia MG sets, and therefore, support the assumptions made in the FSAR.

Therefore, the design, trip level settings, and intended function of the EPAs are both bounded and support the current PNPS FSAR accident analysis.

2. The operation of Pilgrim Station in accordance with the proposed amendment will not create the possibility of a new or different kind of accident.

The proposed change does not affect the operation or intended function of any currently installed safety related equipment. If all the EPAs at one  !

MG fail to open, the redundant train of PPS is still available to mitigate any design basis accident. The EPAs do not perform any specific safety  !

function;- therefore, their failure is bounded by the current Pilgrim Final Safety Analysis.

3. The operation of Pilgrim Station in accordance with the proposed amendment will not involve a significant reduction in a margin of safety.

The EPAs provide no direct safety functions. They isolate non-Class IE RPS power supplies from Class lE power distribution buses upon detection L

of overvoltage, undervoltage, or underfrequency at the RPS power supplies.

Incorporating surveillance requirements for the EPAs into Technical Specifications does not involve a significant reduction in a margin of safety because the surveillance are performed to ensure the EPAs are operable and calibrated to specified values. Ensuring operability and calibration provides confidence the EPAs can perform their intended

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ifunction of protecting RPS components;-from degradation due to overvoltage.

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undervoltage or underfrequency. Confidence. in the EPAs- operability s' Lincreases confidence in the RPS components performing their intended '

. safety function. Increasing' confidence in an intended safety function c being properly performed does not reduce-the margin of safety. q This-proposed change has been reviewed and approved by the Operations Review Committee, and reviewed by the Nut.1 car Safety Review and Audit Committee.

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, This change will be implemented within 30 days following BECo's receipt of its l: approval'by the NRC.

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