ML20209H855

Forwards Guidelines for Human Factors Maint Plan Re SPDS Display Formats & Techniques.Util Intends to Refer to Guidelines in Resolution of 850815 Human Engineering Deficiencies

ML20209H855
Person / Time
Site:	Fort Calhoun
Issue date:	09/05/1986
From:	Andrews R OMAHA PUBLIC POWER DISTRICT
To:	Thadani A Office of Nuclear Reactor Regulation
References
LIC-86-232, NUDOCS 8609160035
Download: ML20209H855 (11)

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l Omaha Public Power District 1623 Harney Omaha, Nebraska 68102 2247 402/536 4000 September 5, 1986 LIC-86-232 Mr. Ashok C. Thadani, Project Director PWR Project Directorate #8 Division of PWR Licensing - B Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Washington, DC 20555

References:

1. Docket No. 50-285

2. Letter OPPD (R. L. Andrews) to NRC (E. J. Butcher) dated August 15, 1985 (LIC-85-373)

3. Letter OPPD (R. L. Andrews) to NRC (A. C. Thadani) dated January 28, 1986 (LIC-86-025)

Dear Mr. Thadani:

Safety Parameter Display System Human Factors Review Omaha Public Power District (OPPD) submitted a letter dated August 15, 1985 concerning the human factors review of the Safety Parameter Display System (SPDS). The submittal included our contractor's report of the Human Factors Review and OPPD's conclusions and plans relative to that report. A brief schedule for resolution was provided with each Human Engineering Deficiency l (HED) which noted that either a change would be made, a change could not be made, or a change would be reviewed.

l In Reference 3, OPPD noted that with respect to the HED's for the SPDS, a determination of whether or not changes would be made was scheduled for December 1986. The changes would then be implemented over the 1988 and 1990 refueling outages.

In early 1986, Mr. Leo Beltracchi and Mr. Ed Tourigny of the NRC made a visit to OPPD to see the SPDS and to discuss the human engineering deficiencies rela-tive to the SPDS. The visit resulted in a discussion of OPPD's submittal on the human factors review of the SPDS. Mr. Beltracchi was concerned that from the Reference 2 report, it appeared that OPPD was not intending to do anything to resolve the rather large number of HED's. OPPD categorized the HED's for Mr. Beltracchi in order to demonstrate that the majority of the HED's identi-fied in the report were not specific to the SPDS, but were applicable to some 360916oo35 860905 5 i PDR ADOCK 0500 1 ' \

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Mr. Ashok C. Thadani LIC-86-232 Page 2 facet of the Emergency Response Facilities Computer System. OPPD also demon-strated that many of the HED's had already been corrected. Because the human factors review done by 0 PPD's contractor resulted in a report which did not distinguish between the SPDS functions and the other computer functions, OPPD had addre sed each comment in the contractor report as an HED in order to provide coverage of the findings.

Two items of concern were raised by Mr. Beltracchi during his visit. The first concern was that the SPDS work station in the control room was not " useable" due to its inconvenient location and lack of workspace. Mr. Beltracchi request-ed that something be done prior to declaration of operability. The workstation has been relocated to alleviate Mr. Beltracchi's concerns. Secondly, Mr.

Beltracchi noted upgrades to the SPDS to resolve HED's were being done without formal human factors guidelines. In order to avoid needing a new Human Factors Review after the upgrades are completed, he requested that OPPD finalize its Human Factors Maintenance Plan relative to software / computer applications so that these guidelines could be used in the resolution of the SPDS HED's.

OPPD has finalized the portion of the Human Factors Maintenance Plan relative to "SPDS display formats and techniques." As requested, these guidelines are being submitted for your information. OPPD intends to refer to these guide-lines in the resolution of the Reference 2 HED's. The schedule for completion of upgrades remains as stated in Reference 3. Those HED's specific to the SPDS will receive a higher priority than HED's for the remainder of the computer system.

If you have further questions concerning this, please do not hesitate to contact us.

Sincerely hbm R. L. Andrews J

Division Manager Nuclear Production RLA/me Attachment cc: LeBoeuf, Lamb, Leiby & MacRae 1333 New Hampshire Ave., N.W.

Washington, DC 20036 Mr. D. E. Sells, NRC Project Manager Mr. P. H. Harrell, NRC Senior Resident Inspector

Section 1. General Human Engineering Considerations 1.1 General Considerations (1) SPDS parameters should be consistent with the Emergency Operating Procedures (EOPs) .

(2) Human engineering must take into account conventions of style and information content that the operator expects because the SPDS is a retrofit to the power plant.

(3) Good human engineering must include end user (i.e. operator's and STA's) involvement in the design process.

(4) Human engineering considerations must be reconciled with existing hardware /sof tware limitations.

(5) Training must be given to SPDS users when changes to displays are completed.

Section 2. SPDS Display Formats 2.1 General Considerations 2.1.1 The SPDS should provide a concise display of critical plant varia bles . The display should help the operator compare data from related plant functions and assess the saf ety status of the plant.

2.1.2 The SPDS should give operators information about system status and parameter values that is needed to meet task requirements in normal, abnormal, and emergency situations.

2.1. 3 To prevent operator confusion, it is essential that displays be identified as to whether they reflect demand or actual status. Actual system / equipment status should be displayed for important parameters.

2.1.4 Parameter scan times and display update frequencies should be consistent with that needed for emergency conditions.

2.1.5 The displays should be designed to enhance efficient understanding by the user.

(1) There should be as much consistency as possible over all of the displays within the system.

(2) Efficient performance requires not only display of needed information but also avoiding the display of extraneous inf ormati on.

(3) Redundancy in the presentation of information items should be limited to cases where needed for backup or to avoid excessive operator movement or excessive changing of display pages.

(4) There should be minimal memorization required by the user.

2.1.6 The SPDS should provide " single-button" access to top and mid-level saf ety f unction displays for simple user interface.

2.1.7 Display call-up times for top and mid-level displays should be less than 2 seconds and not canpromised by changes to the system.

2. 2 Primary and Secondary Display Formats During plant operation, the primary SPDS display should accurately indicate the status of important plant functions.

2.2.1 The design of the display should have a single primary display format for each mode of plant operation. However, display formats composed of the same sets of variables or the same sets of hierarchical displays may be used in common for several modes of plant operation.

2.2.2 When a system of primary and secondary display formats (a hierarchical display) is used, the display formats should be ranked one above

another in a systematic order of importance to facilitate access to information and to make it easy to manipulate the displays.

2.2.3 The combined primary and secondary SPDS display formats should provide data on the complete set of variables used to assess the plant's safety status.

2.2.4 The top level display format of a hierarchical SPD6 display system should provide the operator with enough information to detect a change in the plant's saf ety status and to select appropriate lower level displays formats.

2.2.5 The display system should allow the operator to readily select all levels of display format.

2.2.6 If the primary display format is not continuously visible, provisions should be made to notify the operator about important changes in the status of plant f unctions that require attention.

2. 3 Organization of Data The format used in presenting data to operators is an important factor in preventing reading and selection errors, and reducing search time.

Acceptable formats may present information about the plant's saf ety status in combinations of alphanumeric, symbolic, or graphic form, and may present data about plant variables in analog or digital form.

2.3.1 The operator should have some capability for controlling the amount, format, and complexity of information (e.g. , file dumps, program outputs, error messages) being displayed by the system.

2.3.2 The amount of information-bearing activated screen area should not exceed 25 percent of the total screen area.

2.3.3 Organization of Data (1) Displayed data should be organized in a logical, consistent manner.

(2) Displayed data should reflect some obvious and inherent quality of the data groups (e.g. , chronological, hierarchical, sequential, or mimic relationships).

(3) Organization and separation of information subgroups should be made apparent to the operator through the use of blank spaces, lines, or some other form of visible demarcation.

(4) Physical location of specific data groups (e.g. , alarms, menus) on the screen should be consistent.

(5) The manner of presentation of identical data should be based on the uses to which the data will be put by the operator.

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( 6) Within the limits of ( 5) a bove, identical data in different presentations should be displayed in a consistent, standardized manner.

2.3.4 Labeling (1) Display names should be in double character height just above the SPDS matrix in the lower lef t of the screen. Display numbers should be in double character height just above the ESF matrix in the lower right of the screen.

(2) Each individual data group or message should have a descriptive ti tle.

(3) Labels should reflect some unique characteristics of the content of the data group or message.

(4) Words should be correctly spelled.

( 5) Labels should be located in a consistent manner either above or to the lef t of the data group or message they describe.

(6) Labels should be oriented horizontally.

(7) Labels should be highlighted or otherwise accentuated to f acilitate operator scanning and recognition.

(8) Labels should be consistent in their use of acronyms, abbreviations, and part/ system numbers.

(9) Nomenclature used in labels should be consistent with that used in procedures.

2.3.5 The following standardized fields should be used:

(1) Telephone Number: (402) 536-4732 (2) Time: HH:MM:SS (3) Date: DD MMM YY 2.3.6 Lis ts (1) Lists should be vertically aligned and lef t-justified.

(2) Indentation should be used for subclassifications.

(3) Items contained in a numbered 1,ist and described on " continue" pages should be numbered relative to the first number on the i first page of the list.

(4) Lists of options should be organized according to the probability

of selection for each item, with high probability items presented first.

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(5) When presenting a list of operator options, the label should reflect the question or choices being posed to the operator.

(6) Non-option lists or equal-probability options should be presented in alphabetical or numerical order.

(7) When directions to the operator accompany a list of options, such

. directions should precede presentation of the list.

2.3.7 Menus (1) Numbers should be used as designators when listing selectable items.

(2) Nunerical designators should start with the number "1" (not zero).

(3) If the use of numbers as designators would create conf usion

! becuase of other numbers which make up the item to be designated, alphabetic characters should be used.

(4) When used, alphabetic designators should start with the letter "A".

(5) Selection designators in menus should be separated f rom text descriptors by at least one blank space.

2.3.8 Quantitative data which must be scanned and compared should be presented in either tabular or graphic form.

(1) When presented in tabular f orm, nuneric data should be right-justified with decimal points aligned.

(2) When presented in tabular form, alphanumeric data should be lef t-justified.

2.4 Trend Data 2.4.1 Quantitative information about the magnitudes and time-dependent trends of the variables shown on the SPDS should be presented to help the operator assess the severity and dynamics of abnormal plant condi tions.

2.4.2 Magnitude and trend data may be provided on lower level display formats, as long as the SPDS design all'ows the operator to readily acquire this information.

2.4.3 CRT-displayed trend plot scales should be consistent with the intended f unctional use of the data. (For example, the monitoring of neutron flux at reactor trip may have a variable scale of 0 to 100 percent of the design value and a time scale resolution of seconds. H owever, post-trip monitoring may have a variable scale of 0 to 10 percent with a time scale resolution of minutes. Finally operational log data of neutron flux may have a time scale resolution of hours.)

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2.4.4 The time-history should cover enough time and be accurate enough to depict the onset and development of conditions that vary f rom the preceding normal operating conditions.

2. 5 Bar Chart 2.5.1 A bar chart may used to synthesize an array of analog meters, with each bar representing a specific variable.

2.5.2 Each bar on the display should have a unique label that positively identifies the variable.

2.5.3 The length of each bar should be proportional to the magnitude of the variable it represents.

2.5.4 A bar chart should provide a reference to the normal operating value of each variable displayed.

2.5.5 A bar chart should indicate the normal operating range of the variable, if the operating range is a significant fraction of the total range.

2.5.6 A bar chart should not be used as the sole means of alerting the operator to abnormal conditions.

2.5.7 When color coding is used to signal that a variable is outside its normal range, a bar color that does not attract attention should be used while the variable is normal. An attention-getting color should i

be used when a variable exceeds the normal range.

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Section 3. SPDS Display Techniques 3.1 General Considerations The displayed information should be readily perceived and comprehended by SPDS users. Pattern and coding techniques should be used as perceptual cues to help the operator detect and recognize unsafe plant operating condi tions.

(1) The SPDS display should provide enhancements to improve the operator's perception, canprehension, and detection of operating conditions that may affect the plant's saf ety status.

(2) The display of these conditions should be distinctly different in appearance f rom the display of normal operating conditions.

3. 2 Graphic Representation of Variables 3.2.1 SPDS Display Scaling (1) A linear relationship between the display element and the variable it represents should be used, unless a nonlinear (e.g.,

logar i thmic) relationship is more appropriate.

(2) Limit marks should be used for each critical plant variable displayed. The limit marks should be representative of operational limits established by techical specifications, process limits, and saf ety system actuation setpoints, if I applica bl e.

(3) Scaling should allow tracking of variables over a wide range of abnormal condi tions. Therefore, displays for normal conditions should not fill the entire display area.

(4) The SPDS should alert the operator when a variable is off s cale. Displays may provide a means of reading values if a variable goes off scale during abnormal conditions.

3.2.2 General Scale Characteristics

, (1) Scales should be chosen to provide the necessary range of data and level of accuracy.

(2) Scale units should be consistent with the degree of precision and accuracy needed by the operator.

r (3) All displays should indicate values in a form immediately usable l

by the operator without requiring mental conversion.

(4) Percentage indication may be used when the parameter is meaningf ully reflected by percentage.

( 5) Scales should be selected to:

(a) Span the expected range of operational parameters, or (b) Employ appropriate scale ranging techniques, or (c) Be supported by auxiliary wide-range instruments.

(6) If necessary, scale ranges may be expanded (or contracted) by multiplying or dividing indicated scale values by powers of ten. All such scales should be clearly marked as to whether the indicated values should be multiplied or divided, and the f actor involved (e.g., 10, 100, 1000).

(7) Successive values indicated by unit graduations should be one of those shown below or those values multiplied by some power of 10.

GOOD FAIR 1 2 3 4 5 2 4 6 8 10 5 10 15 20 25 20 40 60 80 100 10 20 30 40 50 3.3 Perceptual Aids 3.3.1 Color 3.3.1.1 When color changes are used to indicate a change in functional or operating status, no more than three colors should be used, corresponding to two levels or change in severity of status. A neutral color should indicate normal status.

3.3.1.2 Color codes for the Fort Calhoun SPOS are:

Magenta: Exceeds unsafe value Yellow: In alarm, but less than unsafe Green: Value within acceptable operating limits, equipment "0FF",

circuit breaker open, valve closed , ESF normal.

Red: Equipment "0N", circuit breaker closed, valve open, ESF ON.

Cyan: Information, descriptions, labels White: Indication of additional clarification, used to indicate valves for which the status is not displayed.

3.3.1.3 Displays should avoid conflicts between the use of color coding to enhance colective identification of display elements and the use of color to code changes in operating status of displays, display elements, or displayed variables.

(1) Once colors are assigned a specific use or meaning, no other color should be used for the same purpose.

(2) colors used on the CRT to convey information should be consistent in use and meaning with all other color codes in the control room.

3.3.2 Mimics 3.3.2.1 Color (1) Flow paths should be color coded.

(2) The mimic colors should be discriminably different from each other.

(3) Mimic lines depicting flow of the same contents (e.g. , steam, water, electricity) should be colored the same throughout the control room.

(4) No more than 4 mimic lines of the same color should run in parallel if the operator must quickly identify any one of the lines.

3.3.2.2 Mimic Lines (1) Dif f erential line widths may be used to code flow paths (e.g ,

i significance, volume, level) .

(2) Overlapping of mimic lines should be avoided.

(3) Flow directions should be clearly indicated by distinctive arrowheads.

(4) Mimic origin points should be labeled or begin at labeled components.

( 5) Mimic destination or terminal points should be labeled or er.d of labeled components.

(6) Component representations on mimic lines should be identified.

(7) Component symbols shall be used in accordance with the " Digital Response Table" display currently on the screen. Display numbers should be in double character height just above the ESF matrix in the lower right of the screen.

3.3.3 Blinking Blinking of a symbol or message for purposes or highlighting should be reserved for emergency conditions or similar situations requiring immediate operator actions.

(1) When blinking is used for highlighting', a maximum of 2 blink rates should be used.

(2) When a single blink rate is used, the rate should approximate 2-3 " blinks" per second with a minimum of 50 msec "on" time between blinks.

(3) When 2 blink rates are used, the higher rate should apply to the most cri tical information.

3.3.4 Additional Perceptual Aids 3.3.4.1 Consistent Approach (1) Highlighting methods which have information value beyond their attention-getting quality should have the same meaning in all applica tions.

(2) Highlighting methods associated with emergency conditions should not also be used in association with normal conditions.

3.3.4.2 When contrast enhancement (i.e. , increased illumination intensity level) is used for highlighting, not more than two (preferable) or three (maximum) brightness levels should be used in a single pr esenta tion.

3.3.4.3 Image reversal (e.g. , dark characters on a light background) should

((} be used primarily for highlighting in dense data fields, such as a word or phrase in a paragraph of text, or a set of characters in a table of data.

3.3.4.4 Graphic coding methods (e.g. , symbols, boxes, underlines, colors) should be used to present standard qualitative information to the operator or to draw the operator's attention to a particular portion of the display.

3.3.4.5 Graphic codes, used separately or in combination, should have the same meaning in, all applications.

3.3.4.6 When geometric shape (symbol) coding is used, the basic symbols should vary widely in shape.

3.4 S etpoints Setpoints should be established for variables which are used to initiate changes in display presentation to alert operators to changes in operating status.

(1) Setpoints should be chosen specifically for their suitability to perform the desired function, not arbitrarily established as some nominal percentage of normal value or of maximum range.

(2) Setpoints should be selected so as not to result in frequent f alse alarms or in f ailure to recognize a serious problem.

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