ML20214J852

Sser Accepting SPDS Contingent Upon Resolution of Concerns Re Maint & Improvement of Placement & Visual Access of Containment Isolation Panel & Minor Human Factors Engineering Concerns

ML20214J852
Person / Time
Site:	Yankee Rowe
Issue date:	11/18/1986
From:	NRC
To:
Shared Package
ML20214J423	List: ML20214J447 ML20214J852
References
NUDOCS 8612020004
Download: ML20214J852 (8)

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ENCLOSURE 1 9 I SUPPLEMENTAL SAFETY EVALUATION REPORT INPUT FOR YANKEE R0WE NUCLEKR POWEP STATION SAFETY PARAMETER DISPLAY SYSTEM I. INTRODUCTION All holders of operating licenses issued by the Nuclear Regulatory Commission (licensees) and applicants for an operating license must provide a Safety Para-neter Display System (SPDS) in the control room of their plant. The Commission

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approved requirements for the SPDS are defined in Supplenent I to NUREG-0737 II. BACKGROUND The staff's Safety Evaluation Report (SER) on Yankee Rowe's SPDS was transmitted to the licensee December 17, 1984 (Ref. 1). The SER was based on the staff's re-view of the Yankee Atomic Electric Company (YAEC) Safety Analysis Report. That review identified several questions and concerns but concluded that it was accept-able for the licensee to continue implementing the SPDS progran. YAEC responded to the questions in letters dated April 8 and September 3,1985 (Refs. 2 and 3).

III. EVALUATION The staff, assisted by consultants from Science Applications International Corpora-tion (SAIC),conductedanonsiteauditoftheinstalledSPDS, April 22-23, 1986.

The purpose of the audit was to confirm the closure of the open itens from the earlier review and to ascertain that the SPDS had been installed in accordance with the licensee's plan and was functioning properly. The results of the evalu-ation are summarized below and the contractor's Technical Evaluation Report (TER) l is enclosed to provide further detail. The staff agrees with the technical posi-tions and conclusions contained in the TER.

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-2 A. PARAMETER SELECTION Based on the submittal by YAEC of April 8,1985 and the results of the onsite audit, the staff concludes; (1) that the basis for SPDS parameter selection was appropriate, (2) that the Yankee Rowe critical safety functions provide information equivalent to the NUREG-0737, Supplement I critical safety functions, and (3) that the para-meters selected for SPDS, including containment isolation, provide a complete set of critical safety function information. However, since the containment isolation status display is separate from the SPDS monitor, but is viewable from the location of the SPDS monitor, the staff needs a commitment from the licensee that the relative position, orientation and visual access of the containment isolation status panel with respect to the SPDS station will be maintained or improved. With this con-mitment, the licensee will meet the NUREG-0737, Supplement 1 SPDS requirement for parameter selection.

B. SYSTEM DESIGN The Yankee Rowe SPDS has been defined as the ten emergency operations CRT formats displayed on either, or both, of two CRT monitors. Selection of each display format is accomplished directly by dedicated single action pushbuttons at each monitor.

Essential and non-essential containment isolation status is displayed on a separate panel.

! Display Configuration Staff evaluation of the technical content of the SPDS displays indicated that the safety functions and associated parameters are correctly configured. Evaluation

of the containment isolation display indicated that full or partial isolation can be satisfactorily determined by pattern recognition from the position of either SPDS monitor.

Display Validity ,-

Most SPDS parameters are fed by redundant signals. The algorithms used to support data validity for these redundant inputs are appropriate.

When used alone for single inputs, signal range checks can provide misleadino information. Consideration should be given to developino single input validity algorithms using related variables.

Invalid data are indicated nn the CRT by parameter values displayed in white.

Since a white parameter value can result from several causes (e.g., input failure, offscale, channel value differences), confusion could result unless the operator is trained to always seek other sources of information anytime a white data value appears.

A check of the data validity in the control room during the audit confirmed that the process worked correctly with one exception. The licensee has committed to find the error in the source range indication and correct the problem.

Maintenance and Configur.. tion Control The audit team evaluated the software maintenance and configuration control pro-cess and documentation, and detemined that the current procedures are appropriate to permit satisfactory maintenance and modifications.

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i Security System access is adequately secured by use of passwords to open remote ports after approval of the shift technical advisor.

Isolation Devices The isolation devices protecting the safety related systems from SPDS were approved previously (Ref. 4). The onsite audit confirmed their proper installation in a mild environment.

C. SYSTEM VERIFICATION AND VALIDATION The verification and validation plan for the Yankee Rowe SPDS is documented in NSAC-61. The audit team review of the plan, and verification and validation re-sults, indicate that the process was comprehensively performed.

D. HUMAN FACTORS ENGINEERING With three minor exceptions, the Yankee Rowe SPDS displays good human factors engineering. The three exceptions are as follows: (1) the cyan color has a low contrast ratio with white; (2) the red indicator lights above each of the SPDS

( controls serve no apparent function; (3) there is no audible alarm signal associ-ated with the SPDS alerts, i

E. USE OF SPDS IF OPERATION Durina the onsite audit, licensed operators and other operations and trainino per-sonnel were interviewed, and the operator training program was reviewed. The SPDS operation was demonstrated during normal plant operation. Display call-up response times were observed and system availability calculations were reviewed.

In summary, the Yankee Rowe SPDS is reliable, available, and useful to the opera-tors in both normal and emergency operations. The SPDS has been designed to function as an integrated tool with the upgraded Emergency Operating Procedures and the training program provides for operation both with and without the SPDS available.

IV. CONCLUSIONS The staff conclusions regarding each of the eight SPDS requirements of Supplement 1 to NUREG-0737, based on review of the reference documentation and the attached l

i TER, and on the onsite audit of April 22-23, 1986, are presented below:

1. The SPDS, along with the containment isolation status panel provide a concise display of the critical plant variables.

2. The SPDS is conveniently located as long as YAEC commits to main-taining or improving the relative position, orientation, and visual access of the containment isolation status display with respect to i

• the SPDS station.

3. The SPDS is continuously displayed in the control room.

4. The SPDS is reliable. However, the licensee should evaluate the need to develop more sophisticated data validity algorithms for single input parameters.

5. SPDS electrical and electronic isolation devices are acceptable for interfacing SPDS with safety systems.

6. The SPDS adequately incorporates human factors engineering princi-ples, with the following minor exceptions, which the licensee should address:

o Source range power during power operations indicates a valid reading; o Cyan color used for parameter values has low contrast to the white used for invalid data coding; o Red indicator lights on SPDS control panels serve no function; o There is no audible alarm signal associated with SPDS alerts;

6 o The licensee has not provided NRC with a written response to the DCRDR HEDs related to SPDS;

7. The SpDS and containment isolation status panel provide the minimum information needed to determine plant safety s'tatus with respect to:

o Reactivity control o Reactor core cooling and heat removal from the primary systen o Reactor coolant system inventory o Radioactivity control o Containment conditions.

8. SPDS procedures and operator training, addressing actions with and without the SPDS, have been implemented.

In sunnary, the staff has determined that the SPDS will meet the requirements of NUREG-0737, Supplement 1, when the human factors engineering concerns identified above are resolved, and a commitment is established regarding the relative location of SPDS with respect to the containment isolation status l panel.

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REFERENCES

1. Letter from NRC to YAEC, Revised SER for Yankee Rowe Safety Parameter Display System, December 17, 1984

2. Letter from J. A. Kay, YAEC to J. A. Zwolinski, NRC, Safety Parameter Display Systen, April 8,1985.

3. Letter from J. A. Kay, YAEC to J. A. Zwolinski, NRC, Safety Parameter Display System, September 3,1985.

4. Letter from NRC to YAEC, Safety Evaluation Report - Safety Parameter Display System, March 17, 1986.

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