ML20101G335

Submits Addl Info Re Gessar II Spds,Per NRC Request.Info Re Display Clutter & Reliability Analysis Submitted

ML20101G335
Person / Time
Site:	05000447
Issue date:	12/20/1984
From:	Pfefferlen H GENERAL ELECTRIC CO.
To:	Beltracchi L Office of Nuclear Reactor Regulation
References
RTR-NUREG-0737, RTR-NUREG-737 MFN-173-84, NUDOCS 8412270476
Download: ML20101G335 (4)

Text

o GENER AL $ ELECTRIC NUCLEAR ENERGY BUslNEss OPERATIONS N E C COMPANY

• 175 CURTNER AVENUE e SAN JOSE, IFO NIA95125 December 20, 1984 U.S. Nuclear Regulatory Commission Office of Nuclear Reactor Regulation Division of Human Factors Safety Washington, D.C. 20555 Attention: Leo Beltracchi Human Factors Engineering Branch Gentlemen:

SUBJECT:

OPEN ITEMS FROM DRAFT SER ON GESSAR II SPDS

References:

1) Memo W theEene.T.RusselltoD.Crutchfield,"DraftSERInputfor ral Electric GESSAR II Safety Parameter Display

2) System (SPDS]GuidelinesforControlRoomDesignReviews".

NUREG-0700, Nuclear Reg. Commission September 1981

3) ESD-TR-83-122,"DesignduidelinesfortheUserInterfaceto Computer-Based Information Systems", Prepared by Mitre Cor) oration for the U.S. Air Force, March 1983

4) Tec1. Report TR550-1 " Human Factors and Performance Evalua-tions of ERIS", Prepared by ANACAPA Sciences, Inc. , July 1984 This letter provides information to address the NRC concerns on two open items from the Staff's review of the GESSAR II Safety Parameter Display System (SPDS). The information presented involves:

o Display Clutter o Reliability Analysis Additional draft Safet information on the above two top)ics on the were requested General by the Electric SPDS forNRC in the GESSAR II. y Evaluation Report (Reference 1 Display Clutter The NRC's concern with display clutter pertained only to the RPV Control and the Containment Control displays. General Electric Company agrees that the RPV Control and Containment Control displays contain a large amount of information.

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o USNRC GENERAL h ELECTRf C Page 2-However, the GESSAR II SPDS has been designed to display the information necessary to. work with the Plant Emergency Procedures since the basis for the displays was the Emergency Procedure Guidelines. Additionally, the displays contain the information necessary to satisfy the reguirements for a SPDS which are defined in NUREG-0737,,Supp. 1. General Electric believes that the useful-ness of the extra information outweighs any possible risk of confusion on the part of the operators due to the more complex displays. General Electric also believes that normal training of operators on the displays will-eliminate any significant potential for error.

General Electric believes that the comments and advice received from our human factors engineering consultants, ANACAPA Services, Inc., support our design philosophy. In addition, comments received from reactor operators, who have

-used .the displays under simulated accident conditions, have been very favor-able. Design guidelines pertaining to display density and integration also

' support our designs. For these reasons, as discussed below, General Electric feels that the density of information on the displays in question is appropriate.

1. The density-related guideline for CRT displays in NUREG-0700 (Reference 2) states that the amount of information-bearing activated screen area should not exceed 25% of the total screen area. The two displays in question are admittedly above 25% activated screen area. However, as mentioned previ-ously, the benefits to the operators of including the EPG-related informa-tion were thought to outweig1 the concern of this guideline.

2. The issue of display clutter was discussed during the preliminary stages of.the human factors review of the displays by ANACAPA Sciences, Inc. GE engineers were told by.the Anacapa evaluators that, while information density was high, it seemed to be necessary in view of other display design considerations. These considerations include the necessity to provide the operator with all of the information needed at a particular junction or decision point in the plant Emergency Operating Procedures.

Reference 3 p epared for the U.S. Air Force by the Mitre Corp. went into detail on disp ay design guidelines some of which is ap)ropriate for discussion of isplay clutter. Reference 3 indicates tlat the ideal display should provide the user with all the information needed at the point in the transaction sequence and that type of information should be available at every )oint during the entire transaction. Ref. 3 goes further by saying t1at, whenever possible, all data relevant to the user's current transaction should be included on one display. That way ou don't have to rely on the user to accurately remember data from one dis lay to the next. Thus, the less the operator has to switch between disp ays, the more reliable the overall response should be.

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.USNRC GENERAL $ ELECTRIC Page 3

3. An important part of the dynamic review of the displays at the Perry '

Simulator by ANACAPA Sciences, Inc. (Ref. 4), was the questioning of the o)erators who participated in the evaluation. Operator comments regarding R)V Control and Containment Control displays were overwhelmingly favor-able, Some of their responses are indicated below:

"Very easy to understand".

"No change recommended for layout, it is excellent". '

"Would not add or delete any information".

"Very useful displays" rovide the "Those most displays usable data forare probably an RPV the With problem." mosttwo used because they p(one for R screens one for containment) available, almost all data necessary to handle a casualty can be displayed along with time dependent plots and impor-tant setpoints."

Reliability Analysis The GE assumptions for the overall reliability, system environment and mainte-nance capability is indicated below. These assumptions should be evaluated on a plant-specific basis to determine their applicability and the overall system atailability should be evaluated accordingly.

1. Sensors and wiring to the input modules were not included in the avail-ability analysis. All "important" sensors were assumed to be redundant.

2. Station'A-C and D-C power to the display system was assumed to be present continuously in the analysis. Any potential for power interru be considered for a total power station availability analysis.ption must

3. Routine maintenance was assumed to be performed on a basis that did not impact normal plant o)erations. Any planned outage required for routine maintenance needs to )e factored into the total power station system availability.

4. The analysis assumed the proper (within specification) environment for the equipment. The failure rates used in the analysis are not valid if the environment exceeds the recommended system operating specifications.

5. The analysis uses a 6 hour6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> mean time to repair for most non-VAX computer related equipment and 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> mean time to repair for VAX related items.

Our analysis assumed that sufficient spares, trained personnel and.comput-er maintenance contracts-were in place to provide a mean time to repair consistent with our analysis.

USNRC GENERAL $ ELECTRIC Page 4 We hope that the material discussed in this letter facilitates the resolution clutter'and reliability. If you have any ques-of the open items tions, please contact me on on display (408) 925-3392. ,

Very truly yours, H. C. Pfef erlen, Manager BWR Licensing Programs HCP:rf:rm/G12113 cc: J. Joyce D. Scaletti i

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