ML20236K780

Concludes Ssps General Warning Alarm Reactor Trip Circuit at Facility Included in Ssps Train Actuation Test.Test Frequency Satisfies Requirements of TS 4.3.1.1

ML20236K780
Person / Time
Site:	Catawba
Issue date:	03/09/1992
From:	Newberry S Office of Nuclear Reactor Regulation
To:	Matthews D Office of Nuclear Reactor Regulation
Shared Package
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References
FOIA-98-155 TAC-M82238, TAC-M82239, NUDOCS 9807100078
Download: ML20236K780 (3)

Text

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. s i 3 # '9,, UNITED STATES i

i [ g NUCLEAR REGULATORY COMMISSION

WASHINGTON, D. C. 20666 March 9, 1992 n MEMORANDUM FOR

David B. Matthews, Project Director Project Directorate 11-3 Division of Reactor Projects I/II l

i FROM: Scott Newberry, Chief  ;

Instrumentation and Controls Systems Branch l Division of Systems Technology

SUBJECT:

GENERAL WARNING ALARM REACTOR TRIP IN THE WESTINGHOUSE PROTECTION SYSTEM DESIGN (TAC NOS. M82238 AND M82239)

Plant Name: Catawba Units 1 and 2 Utility: Duke Power Company TAC Nos.: M82238/M82239 l Docket Nos.: 50-413/414 l Operating License: OR Project Directorate: 11-3 Project Manager: ' R. Martin Review Branch: SICB/ DST Review Status: Complete

REFERENCES:

(1) MEMORANDUM FROM E. MERSCH0FF TO G. LAINAS DATED NOVEMBER 4,

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1991, TIA 91-35 " CATAWBA NUCLEAR STATION TECHNICAL SPECIFICATION 3.3.1, ITEM 20, AUTOMATIC TRIP AND INTERLOCK LOGIC",

(2) WESTINGHOUSE SSPS INSTRUCTION MANUAL CNM-1399.08-15, PAGES 2-86 THRU 2-90, AND (3) DUKE POWER CATAWBA STATION SSPS TRAIN A PERIODIC TESTING PROCEDURE IP/I/A/3200/02A By TIA 91-35 technical (Reference specification (TS 1),) Region 11 requested NRR to investigate therequireme the Westinghouse protection system design, specifically, to determine:

(1) What part of the SSPS ar.d associated logic is included under TS 3.3.1, Item Number 20, in particular, with respect to the SSPS general warning reactor trip, and (2) What constitutes adequate testing of the general warning reactor trip logic as it relates to satisfying the requirements of TS 4.3.1.1.

In the Westinghouse solid state protection system (SSPS) design, each of the two protection system trains is continuously monitored by the general warning alarm reactor trip subsystem. The warning circuits are activated if undesirable train conditions are set up by improper alignment of testing systems, circuit malfunction or failure. A trouble condition in a logic train is indicated in the control room. If any one of the conditions listed below exists in train A at the same time any one of the conditions exists in train B, the general warning alarm circuits will automatically trip the reactor.

Contact:

H. Li, SICB/ DST 504-2846

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9807100078 980624 PDR FOIA

,UNNERS798-155 PDR _

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j David B. Matthews March 9, 1992 The conditions that actuate the general warning alarm are as follows:

a. Loss of either of two 48 volt de or either of two 15 volt de power supplies

b. Printed circuit card improperly inserted

c. Input Error Inhibit switch in the INHIBIT position j

d. Slave relay tester Mode Selector in TEST position

e. Multiplexing selector switch in INHIBIT position

f. Bypass breaker of train not being tested racked in and closed

g. Pemissive or Memory test switch not in 0FF position

h. Logic Function test switch not in 0FF position j The conditions listed above indicate that the primary function of the general warning alarm is to aid the operator to maintain the proper alignment of the protection system, especially during and after the testing of a protection i system train. The reactor trip function by the general warning alarm circuitry l is a conservative approach to protect against failures from human errors i following testing or maintenance. -

A telephona conference was held between the staff and the Duke Power Company (Catawba licensee) on February 5,1992, to discuss the testing capability of the general warning circuits. Duke Power Company provided a copy of the vendor's instruction manual with respect to General Warning Alarm Circuits (Reference 2). The circuitry is located on the SSPS semi-automatic tester board. The detection circuit includes a general warning relay K524 and a string of LED indicators. Each LED indicator represents a specific condition that will cause a general warning alarm. These conditions include loss of power supply, removal of a printed circuit card, placement of switches within the train to positions used during testing, position of the reactor trip bypass breaker for the train not being tested. The detection circuits require constantly grounded inputs in order to prevent the alam from being turned on.

The breaking of any ground path, such as a test switch not in its normal l

position or bypass breaker being set, will cause a general warning alam.

The licensee has integrated the general warning alam circuit tests in the SSPS periodic test procedure (Reference 3). That procedure requires testing general warning relay K524 once every 62 days on a staggered test basis.

Since the components in the detection circuitry for other inputs are limited 1 to resistors, diodes and switch contacts which are setup by continuously monitoring the nomal status to prevent the alarm being turned on (any failure in these inputs will turn on the alarm), it is a fail-safe arrangement.

Therefore, there is no need to test each input on a periodic basis.

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y Masch 9, ic92

$ David B. Matthews Based on the audit review of the documents in References (2) and (3), the staff concludes that the SSPS general warning alarm reactor trip circuit at Catawba has been included in the SSPS train actuation test (TS 3.3.1, item 20),

! and the test frequency satisfies the requirements of TS 4.3.1.1.

By copy of this memorandum, the Technical Specification Branch is requested to l Verify that the Westinghouse standard TS has addressed the testing of the I I

general warning alars circuitry. A general note, inserted into TS Table 3.3.1 to state that the general warning alarm circuit should be tested under TS ~

3.3.1, Item 20, would be appropriate.

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1 Scott Newberry, Chief Instrumentation and Controls Systems Branch Division of Systems Technology cc: A. Thadani *

,, G. Lainas 1 R. Martin C. Grimes S. Imch 4

C. Schulten I. Ahmed l

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