ML20096F053

Forwards Writeup of Loose Parts Monitoring Sys Which Will Appear in Ssar Via Upcoming Amend

ML20096F053
Person / Time
Site:	05200001
Issue date:	05/14/1992
From:	Fox J GENERAL ELECTRIC CO.
To:	Poslusny C NRC
References
NUDOCS 9205200161
Download: ML20096F053 (9)

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175 Curtner Avenue San Jose, CA 95125 Phone (408) 925 4 8'2A FAX (408) 925-1193 or (408) 925-1687 Subject L_oose Pc d.s M o m M ov' m y S O 3 b Message ck A- ---

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Standard Plant CHAPTER 4 TABLE OF CONTENTS (Continued) l Section Illlt P.agt 4.4.2 Description of the Thernal and Hydraulie Design of the Reactor Coolant Sptem - 4.4 2 4.43 Intx: Lgo5e Por 4.4 4 m

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43 . REACTOT! MATERIALS

-4.5.1 Control Rods Sptem Structunt Materials 4.51 4.5.2 Reactor Internal Materials 4.53 - -

4.53 Interfaces 43-4a 4.6 Bd.CDD1%.DI, SIGN OF REACTIVTIY COVTRhi.5Y33IMS  ;

4.6.1 Information for Control Rod Drive Sptem 4.6 1 4.6.2 Evaluations of.the CRDs 4.6-10' 4.63' Testing and Baluation of the CRDs 44 13 444 Information for Combined Performance of Reactivity Control Sptems 4.6-16

--4.6.5 Evaluation of Combined Performance 4.616 APPENDIX 4A TYPICAL COh"lROL ROD PATTERNS AND ASSOCIA*IID POMTR -

DISTRIB1 MON FOR ABWR 4A 2 APPENDIX g _ FUEL UCENSING ACCEPTANCE CRITERIA APPENDIX fC. CONTROL ROD LICENSING ACCF.PTANCE CRITERIA 4 111 Amendmem 5

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, .n ' SECTION 4.4

'l CONTENTS (Continued) 1 Section Mt East 4.4.2.1.2 Reactor Coolant Sprem Therma 1 Hydraulic 4.42 is Data 4.4.2.13 Reactor Coolant Sptem Geometric Data 4.4.2 4.4.2.2 Operating Restrictions on Pumps 4.4 2

.4.4.23 Power Flow Operating Mar 4.43 Limits for Normal Operations 4,4-2

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4.4.23.2 Other Performance Characteristics 4.62 4.4.23.3 ReSi ons of the Power Flow Map 4.4-3 4.4.23.4- Design Features for Power Flow Map 4.&3

- 4.4.23.5 . Flow Contrel 4.43

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4.4.2.4 . Thermal and Hydepulic Characteristics 4.43 p Sumaary Table 4etenfeses eou u c w r.e hEnve'b'" 4.44

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4.44 4.451. Powtr Flow Operating Map L

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1. [4A.3 Loose-PartsMonitoringSystem. -y  ;

v7 . The applicant referencing the ABWR design ~

t-shall provide alloose parts monitoring system on'

- - the reactor pr' essure vessel, and implernent a' ,

2 loose parts detection program whleh conforms to i the guidelines of the regulatory-position -

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contained in Regulatorr Onide 1.133.' The designi (:;--- INSGM.k of the loose parts monitoring system is deferred -

f so that it may be' defined utill21ag commercially

availible componer.ts, at the time of construe. -

l tion, integrated with other instrumentation.

-systems and it can reflect the applicants preference and experience. :Se'e Subsection Q4,4.3 for laterface requirements; Fw 74,43 gag,,q,,,,. cod U c.e.wra Mem oboA ,

L4.4.4.1 Fower Flow Operatink Map The specific power flow operating map to be

used at the plant will be provided by the utility to the USNRC for information. )

{4.4.4.2 neraal Limits = '

L The thermal limits for the core loading at

, th'c ytant will be provided by the utility to the USNRC for Information. ,

4,4.4J Loose parts Moaltoring System

)- i 1The applicant referencing the-ABWR design- '

e, > twill provide a loose parts monitoring system and: *7

- implement a loose-parts. detection program'(See ik Subsection 4.4.3). {.

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. l t4 SGftT A The j'cose farts)fonitoring Jystem (LPMS) is designed to provide detection of ,

loose metallic parts within the reactor pressure vessel. Detection of loose parts can provide the time required to avoid or mitigate safety related damage to or malfunctions of primary system components. LPMS detect structure borne sound that can indicate the presence of loose parts impacting against the reactor pressure vessel internals. The system alarms when the signal amplitude exceeds preset limits. The LPMS detection system can evaluate some aspects of selected signals. However, the system by itself will not diagnose the presence and location of a loose part. Expert diagnostic by an experienced LPM engineer is required to confirm the presence of a loose part.

4.4.3.1 Power Generation Design Bases The LPMS is designed to provide detection and operator warning of loose parts in the reactor pressure vessel to avoid or mitigate safety-related damage to or malfunctions of primary system components. The LPMS is not classified as a safety-related system, although it is designed in conformance withgegulatory Guide _1.133.

Additional design censideratiens provide for the inclusion of electronic features to minimize operator interfacing requirements during normal oparation and to enhance the analysis function when operator action is required to investigate potential loose parts.

4.4.3.2 System Description The LPMS continuously monitors the reactor pressure vessel and apourtenances for indications of loose parts. The LPMS consists of sensors, ca)1es, signal conditioning equipment, alarming monitor, signal analysis and data acquisition equipment, and calibration equipment. The alarm setting for

.each sensor is determined after system installation is complete. The alarm setting is set low enough to meet the sensitivity requirements, yet is designed to discriminate between normal background noises and the loose part impact signal to minimize spurious alarms. Each sensor channel is isolated

- to reduce the possibility of signal ground loop problems and to minimize the background noise. Background noises are also minimized by use of tuned filters. ' A disable signal is provided during control rod movement and other plant maneuvers that may initiate a spurious alert-level alarm.

LPMS sensors aro usually accelerometers. The array of LPMS accelerometers typically consist of twelve to twenty sensors that are strategically mounted on the external surface of the primary pressure boundary at various r

elevations and azimuths at natural collection regions for potential loose parts. General mounting locations are at the a) main steam outlet nozzle, b) feedwater inlet nozzle, c) core spray nozzles, and d) control rod drive housings. Tne sensors will be mounted in such a fashion as to provide high l

frequency response and sensitivity.

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. JThe online system sensitivity is such that the system can detect a metallic

1oo'se part that weighs between 0.25 lb to 30 lbs and impacts with a. kinetic-tenergy_of 0.5 ft-lb on.the.inside surface of the reactor pressure vessel within 3 feet of.a-sensor.- The LPMS frequency range of interest is

-typically from 1 to-10 kHz. Frequencies lower than ~1 kHz are generally associated with flow induced vibration signals or flow noise, Physical separation is maintained from the sensors at each natural collection region to an area where-they are combined and routed through the cable penetration to a termination point. The termination point is at a point'in the plart.that is accessible for maintenance _during full power operation.

The LPMS includes ~ provisions for both automatic and manual start-up of data acquisition equipment with automatic activation in the event the preset

. alert level is reached or exceeded. The system also initiates an alarm to

the control room personnel-when an alert condition is reached. The data acquisition system will automatically select the alarmed channel plus additional channels for simultaneous recording. The signal analysis-equipment willf allow-immediate visual and audio monitoring of all signals.

Provisions exist for-periodic online channel check and functional tests and for offline channel calibration during periods of cold shutdown or .

refueling.:- The LPMS electronics is designed to facilitate the recognition, location, replacement, repair, and adjustment of malfunctioning-LPMS components.. The <lPMS components-located inside the containment have baen i designed-and--installed perform their function following all_ seismic events that do not_ require plant shutdown, up to and including the Operating Basis Earthquake..'The LPMS components selected for this application are rated to meet the normal c aerating radiati.on, vibration, temperature, and humidity environments in witch the components are installed.

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A11~LPMS_ component: within the corta ment are designed for a pfyear design

-life. In those instances where-a year design life is not practicable, a replacement program'will be established for those parts that are anticipated

- to have limited-. service life.

.4.4.3.3 Normal System Operation

. The LPM 1will be set to alarm for detected signals having characteristics of metal-to-metal impacts.

After; installation # the sensor array, the LPMS overall and individual channels can be characterized at plant start-up before' operation monitoring.

Each accelerometer channel will exhibit its own particular and unique frcquency spectrum.< This frequency signature, or normal background noise, L results from-a combination of both internal and external sources due to j snormal and transient conditions.

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• : \ td SWLT A ( Co uD Y-Calibration'is an important-part of LPMS operattun. The LPMS is calibrated to detect a loose part with minimum impact energy of 0.5 ft-lb within 3 feet of a sensor. Alarm level setpoint is determined by using a manual calibration device to simulate the presence of a loose part impact near each sensor. The setroint it, typically a based on a percentage of the calibration signal magnitude, and is a function of actual background noise.

Additionally, calibrated impacts at various locations near the sensors assist in diagnosing the source of the signal.

Discrimination logic is typically incorporated in the LPMS to avoid spurious alarms. Discrimination logic rejects events that do not have the characteristics of an im>act signal of a loose part. Typical discrimination functions are based on t1e length of time the signal is above the setpoint, the number of channels alarming, the time between alarms, the repetition of the signal, and the waveform and frequency content. False alert signals due to plant maneuvers are avoided by the use of administrative procedures by control room personnel.

Once an unusual signal characteristic of a metal-to-metal impact is detected by the loose parts monitcr, it is essential to determine the source or cause of the alarm. An alarm does not necessarily indicate the presence of a loose part in-the reactor. The alarm could be caused by electrical noises, system malfunctions, limitations in alarm logic, or non-impact noises. The LPMS detection system is designed to incorporate the discrimination logic to distinguish between an actual loose parts signal and a non-loose parts signal before signaling the control room operator.

Usually the plant. operator makes the preliminary evaluation based on the available information. If the presence of unusual metal impact sound is ii.dicated, then the station engineers perform additional evaluation. LPH experts are required to correctly diagnose the p*esence and location of a loose part. In order to reach proper conclusions, various factors must be considered such as: plant operating conditions; location of the channels

-that alarmed; time differences between when the wave arrived at different locations; 2nd comparison of the amplitude and frequency contents of the signals with known normal operation data.

4.4.3.4 Safety Evaluation The LPMS is intended to be 'used for information purposes only by the plant o)erator. The plant operators do not rely on the information provided by tie LPMS for the performance of any safety-related action. Although the LPMS is not classified' as a' safety-related system, it is designed to meet the seismic and environmental operability recommendations of Regulatory Guide 1.133.

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'i (N 3gg;p A ( C O N T) 4.4.3.5 Test and Inspection The LPMS will be calibrated to detect a metallic loose part that weighs from 0.25 lb to 30 lbs and impacts with a kinetic energy of 0.5 ft-lb within 3 feet of each sensor. Provision will be made to verify the calibration of the LPMS'at each refueling. The system will be recalibrated as necessary when found to be out of calibration. A test and reset capability will be included for_ functional test capability.

The manufacturer will provide services of qualified personnel to provide technical guidance for installation, start-up, and acceptance testing of the-system._ In' addition, the manufacturer will provide the necessary training of plant personnel for proper system operation and maintenance and planned operating.and record-keeping procedures.

4.4.3.6 Instrumentation Application The LPMS consists of sensors, cables, signal conditioning equipment, alarming monitor, signal analysis and data acquisition equipments and calibration equipment.

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