ML20062B794

Monitoring of Electric Power to Reactor Protection Sys for Pilgrim Nuclear Power Station, Technical Evaluation Rept

ML20062B794
Person / Time
Site:	Pilgrim
Issue date:	04/29/1982
From:	Selan J LAWRENCE LIVERMORE NATIONAL LABORATORY
To:	NRC
Shared Package
ML20062B783	List: ML20062B781 ML20062B785 ML20062B794
References
CON-FIN-A-0250, CON-FIN-A-250 NUDOCS 8208050044
Download: ML20062B794 (7)

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UCID- 19134 TECHNICAL EVALUATION REPORT ON THE MONITORING OF ELECTRIC POUER TO THE REACTOR PROTECTION SYSTEM FOR THE l PILGRIM NUCLEAR POWER STATION Janes C. Selan (Dochet No. 50-293) l April 29, 1982 0

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i DISCLAPMER l

l This document was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, expressed or implied, or amumes any legal liability or responsibility for the accuracy, completeness. or usefulness of any information. apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufac-turer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.

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i ABSTRACT l i

This report documents the technical evaluation of the monitoring of electric power to the reactor protection system (RPS) at the Pilgrim Nuclear Power Station. The evaluation is to determine if the proposed design modification will protect the RPS from abnormal voltage and frequency conditions which could be supplied from the power supplies and will meet certain requirements set forth by the Nuclear Regulatory Commission.

The proposed design modifications will protect the RPS from sustained abnormal voltage and frequency conditions from the supplying sources.

FOREWORD i

This report is supplied as part of the Selected Electrical, Instrumentation, and Control Systems Issues Program being conducted for the U. S. Nuclear Regulatory Commission, Office of Nuclear Reactor Regulation, Division of Licensing, by Lawrence Livermore National Laboratory.

The U. S. Nuclear Regulatory Commission funded the work under the authori:ation entitled " Electrical, Instrumentation and Control System Support,' 3&R 20 19 04 031, FIN-0250.

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TABLE OF CONTENTS Page

1. INTRODUCTION . . . . . . . . . . . . . . . 1 i

2. DESIGN DESCRIPTION . . . . . . . . . . . . . 2

3. EVALUATION . . . . . . . . . . . . . . . 3

4. CONCLUSION . . . . . . . . . . . . . . . 4 REFERENCES . . . . . . . . . . . . . . . . 5

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TECHNICAL EVALUATION REPORT ON THE -

s MONITORING OF ELECTRIC POWER TO THE REACTOR PROTECTION SYSTEM ATsTHE PILGRIM NUCLEAR POWER STATION (Docket No. 50-293)  %

James C. Selan [o g Lawrence Livermore National Laboratory, Nevada

1. INTRODUCTION During the operating license review for Hatch 2, the Nuclear-Regulatory Commission (NRC) staff raised a concern about the capability of th0 Class 1E reactor protection system (RPS) to operate af ter suffering sustained, abnormal voltage or frequency conditions from a non-Class lE power s'upply. Alnarmal voltage or frequency conditions could be produced as a result of one of the following causes: combinations of undetected,

'I random single failures of the power supply components, or multiple failures of the power supply components caused by external phenomena such as a seismic event. ,

The concern for the RPS power supply integrity is generic to all General Electric (GE) boiling water reactors (BWR) MARK 3's, MARK 4's, and MARK 5's and all BWR MARK o's that'have not elected to use the solid state RPS design. The staff therefore pursued a generic resolution. Accordingly, GE proposed a revised design, in conceptual form, for resolution of this concern [Ref. 1]. The propssed modification consists of the addition of

,, two Class lE " protective packages" in series between each RPS motor-generator (M-G) set and it's respective RPS bus, and the addition of two similar packages in series in the alternate po.w,er source circuit to the RPS buses.

E5/h protective package would include a breaker and associated overvoltage,

', uidervoltage and underfrequency relaying. , Each protective package would meet the testability requirements for Class lE equipment.

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~' With the protective packages installed, any abnormal output type

, failure (undetectable random or seismically caused) in either of the two RPS s 4 M-G sets (or the alternate supply) would result in a trip of either one or

. both of the two Class lE protective packages. This tripping would interrupt

q the power to the effected RPS channel, thus producing a scram signal on that

+, channel, while retaining full scram capab$lity by means of the other channel.

-~ ' Thus, fully redundant Class lE 'pfotection is provided, bringing the overall k g

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3. EVALUATION The NRC stated several requirements that the licensee must meet in their design modification to monitor the power to the RPS. A statement of these requirements followed by an evaluation of the licensee's submittals are as follows:

(1) "The components of the RPS shall not be exposed to unacceptable electric power of any sustained abnormal quality that could damage the RPS."

T1e monitoring module will detect overvoltage, undervoltage, and underfrequency conditions with the following setpoints.

The chosen setpoints (+ 10% of nominal voltage, - 5% of nominal frequency) are within the ratings of the RPS components and thus ensure their protection from sustained abnormal power:

Nominal voltage 118 to 121 volts + 0.5%, 60 Hz nominal (Ref. 11]

Condition Setpoint Time Delay Overvoltage 131.45 volts .10 seconds

+2.31, -2.31 volts +0.04, -0.00 seconds f Undervoltage 107.55 volts .10 seconds

+1.89, -1.89 volts +0.04, -0.00 seconds Underfrequency 57 Hz .10 seconds

+0.04, -0.00 seconds (2) " Disconnecting the RPS from the abnormal power source shall be automatic."

The monitoring module will automatically disconnect the RPS buses from the abnormal power supply af ter the set time delay should the parameters setpoints be exceeded.

(3) "The power monitoring system shall meet the requirements of IEEE 279-1971, CDC-2 and GDC-21."

The monitoring packages meet the Class 1E requirements of IEEE 279, the single failure criteria of CDC-21, and the seismic qualifications of GDC-2.

(4) " Technical Specifications shall include limiting conditions of operation, surveillance requirements, and trip setpoints."

Formal Technical Specifications will be submitted upon final installation and testing of the protective packages. The protective packages are currently planned for installation and operational testing during the first planned outage of sufficient duration (8 days).

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i REFERENCES 1

1. General Electric Company letter, MFN 408-78 (C. G. Sherwood) to NRC (R. S. Boyd), dated October 31, 1978.

2. General Design Criteria-2 (GDC-2), " Design Bases for Protection Against Natural Phenomena," of Appendix A, " General Design Criteria for Nuclear Power Plants," in the Code of Federal Regulations, Title 10, Part 50 (10 CFR 50).

3. General Design Criteria-21 (GDC-21), " Protection System Reliability and Testability," of Appendix A, " General Design Criteria for Nsclear Power Plants," in the Code of Federal Regulations, Title 10, Part 50 (10 CFR 50).

4. IEEE Std. 279-1971, " Criteria for Protection Systens for Nuclear Power Generating Stations."

5. NUREG-75/087, " Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants."

6. NRC memorandum from Faust Rosa to J. Stolz, T. Ippolito, and G. Lainas, dated February 19, 1979.

7. NRC letter to Operating B'4R's, dated September 24, 1980.

S. BECO letter (A. V. Morisi) to NRC (Thomas A. Ippolito), dated j November 26, 1980.

l l 9. BECO letter (A. V. Morisi) to NRC (Thomas A. Ippolito), dated June 17, 1981.

10. BECO letter (A. V. Morisi) to NRC (Thomas A. Ippolito), dated November 18, 1981.

11. Telecon, Ken Eccelston (NRC) and James C. Selan (LLNL), dated April 12, 1982.

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