ML20024F430

Safety Analysis for Parameter Selection for Safety Parameter Display Sys (Spds).

ML20024F430
Person / Time
Site:	Limerick
Issue date:	09/02/1983
From:	PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:
Shared Package
ML20024F428	List: ML20024F427 ML20024F430
References
RTR-NUREG-0737, RTR-NUREG-737 NUDOCS 8309090373
Download: ML20024F430 (2)

Text

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, o ELECTRICAL ENGINEERING DIVISION N3-1, 2301 Market Street i

September 2, 1983 t Safety Analysis for Parameter Selection for Safety Parameter Display System (SPDS)

References:

1) Letter T. J. Dente (BWR Owner's Group) to D. G. Eisenhut, June 1,-1982 "NEDO 24934 Emergency Procedure Guidelines, BWR/1-6 Rev. 2 '

(prepublication form)"

j 2) Letter T. J. Dente to D. G. Eisenhut, October 4, 1982 "Enatta to BWR Emergency Procedure Guidelines"

3) Letter D. G. Eisenhut to T. J. Dente, Feburary 4, 1983

" Safety Evaluation Report on Emergency Procedure Guidelines Rev. 2. NEDO 24934" NUREG-0737 specifies that the principal purpose and function of the SPDS is to aid the control room personnel during abnormal and emergency conditions in determining the safety status of the plant and in assessing whether abnormal conditions warrant corrective action by the operators.to avoid a degraded core. To support this function the SPDS must present information from which the plant safety status can be readily and reliably assessed by control room personnel, who are responsible for avoidance of degraded and damaged core events.

The BWR Owners Group has over the past 2 years developed the Emergency Procedure Guidelines (EPG's) which provide the control room personnel with an operating philosophy for use during these abnormal events. The EPGs for a BWR are symptom oriented, that is the safety status of the plant and correct operator responses are unambiguously e

defined on-the basis of observed symptoms. The EPG development process analyzed a great multitude of conditions with a mixture of

, qualitative and quantitive analysis to determine that the actions based

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on . the occurring symptoms were appropriate . for all events. The analytic basis for 'he ' EPGs and the EPG steps [ reference 1& 2] i were extensively revtewed by the NRC and a Safety Evaluation Report I (SER) [ reference 3] on EPG Revision 2 has been issued, which firmly supports the BWR symptomatic approach.

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, . . . J Part of this effort was to develop a set of entry conditions that identify the symptoms of the plant entering a potential unsafe condition.

- These'have been identified to be the following:

Reactor Pressure Vessel Control i

1.) Low Reactor Pressure Vessel Water Level 2.) high Drywell Pressure 1 3.) Isolation-4 4.) Scram Failure Primary Containment Control 1.) . High Drywell Temperature

2.) High Suppression Pool Temperature i

3.) High Drywell Pressure 4.) High/ Low Suppression Pool Level.

The safety status of a BWR plant can be assessed from the parameters that indicate these entry condition and therefore, constitute the parameters avaliable on the Limerick SPDS. The top level SPDS display presents these parameters with their current value and alarm status.

The next level of displays in the SPDS is derived from the guidelines for RPV Control and Containment Control. The RPV Control Guideline, entered upon the occurrence ci a limit violation of the above parameters guides the control room personnel in simultaneous control of reactor level, pre ssure, and power to maintain the plant in

' a safe condition. The display developed to assist the control room

, personnel in this process contains the basic information required for him to carry out the' procedure. The parameters to be controlled are shown

' with their. current value, recent history, and the significant limits

. associcted with each parameter. The logic for the Containment Control display is similar to the RPV Control display.

In summary, the EPGs have been submitted and approved. The EPG entry: conditions are symptomatic of emergencies and events which may

. degrade into emergencies and the EPG's specify actions appropriate for both. As such the EPG entry conditions are adequate to determine the i safety status of the plant. Since the EPG parameters are the design basis for the Limerick plant SPDS, it is believed that no further i safety analyses are needed. . A review of the method of incorporation of

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, EPG parameters into the SPDS displays should be all that is necessary.

{ Prepared by: y / a f Reviewed by: x m.4 9 3- h

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