ML20209G431
| ML20209G431 | |
| Person / Time | |
|---|---|
| Site: | 05000000, Diablo Canyon |
| Issue date: | 04/16/1985 |
| From: | NRC |
| To: | |
| Shared Package | |
| ML082410749 | List:
|
| References | |
| FOIA-86-197, RTR-NUREG-0737, RTR-NUREG-737 NUDOCS 8704300544 | |
| Download: ML20209G431 (7) | |
Text
i t
ENCLOSURE SUPPLEMENTAL SAFETY EVALUATION REPORT FOR THE DIABLO CANYON SAFETY PARAMETER DISPLAY SYSTEM I.
INTRODUCTION All holders of operating licenses issued by the Nuclear Regulatory Comission (licensees) and applicants for an operating license (OL) must provide a Safety Parameter Display System (SPDS) in the control room of their plant. The Comission approved requirements for the SPDS are defined in Supplement 1 to NUREG-0737 (Ref.1).
4 The purpose of the SPDS is to provide a concise display of critical plant variables to control room operators to aid them in rapidly and reliably detennining the safety status of the plant. NUREG-0737, Supplement 1, requires licensees and applicants to prepare a written safety analysis describing the basis on which the selected parameters are sufficient to assess the safety status of each identified function for a wide range of events, which include symptoms of severe accidents. Licensces and applicants shall also prepare an Implementation Plan for the SPDS which contains schedules for design, development, installation, and full operation of the SPDS as well as a 3
design Verification and Validation Plan. The Safety Analysis and the Implementation Plan are to be submitted to the NRC for staff review.
The results from the staff's review are to be published in a Safety Evaluation Report (SER).
B704300544 870417 kME 197 PDR _
i; li II.
SUMMARY
The NRC staff reviewed the additional information provided by Pacific Gas and Electric (PG&E) in response to requests stated in our SER..
Based on.our review.. we continue to recannend-that hydrogen concentration be displayed within the SPDS. We propose that a condition be added to the license to require this important symptom of a severe accident be displayed on the SPDS.
i III.
EVALUATION A.
BACKGROUND By letter dated September 4,1984 (Ref.2), the Pacific Gas and Electric Company submitted additional information on the SPDS Safety Analysis in response to staff requests and recommendations f
made in our SER (Ref. 3). The staff's SER recommended the j*
display of five additional variables in the Diablo Canyon SPDS.
In addition, the staff's human factors review of the SPDS display 4
l format noted several potential human engineering discrepancies'and d
recommended.that they be assessed for significance and need for correction prior to full implementation of the SPDS. The staff's i
evaluation of the information provided by the Pacific Gas and Electric Company is presented next.
i i
i i
,-... n 4
1
. B.
PARAMETER SELECTION j
The information provided by the Pacific Gas and Electric Company.
states:
"The SPDS display was not intended to be used in conjunction with the Emergency Operating Procedures but to provide a highly reliable display for the operator to assess plant conditions.
Seventeen additional displays were developed to further aid the operator. Eleven displays addressed the Westinghouse Owners' Group's (WOG) Emergency Response Guidelines (ERG),
five specifically keyed to the Emergency Procedures and six reproduced the Critical Safety Function Status Trees. The remaining six displays supply the operato* with information used during normal plant conditions. Appendix A to this enclosure provides illustration of these seventeen displays plus the SPDS display. Because of the high degree of 1
reliability specified in NUREG 0696 for the SPDS, these seventeen displays were not considered as a part of the SPDS.
Parameters suggested as possible additions in the staff's review are included on the secondary displays with the 1
exception of Containment H. The Westinghouse Owners Group's 2
Critical Safety Function (CSF) Status Tree on Containment
i
,_4_
Integ,rity doe:; rot include this parameter, and the ERG's do not refer to it in any immediate action. PG&E oelieves that the inst'alled plant instrumentation is adequate without this parameter."'
\\
The staff held several phone conferences with Diablo Canyon 1
personnel during the period March 26 through April 1,1985. The purpose of these phone conferences was to obtain additional technical data on the monitoring of hydrogen concentration within the Emergency Operations' Procedures, the response time of hydrogen monitors, containment size, and the location of the I
L hydrogen concentration display within the con' trol room.
In addition to this information, we note that the staff's SER on the Westinghouse Emergency Response Guidelines (Ref. 4) indicates that the absence of H from status trees is an item requiring 2
further consideration.
1 l
?
Based on thei review of the infonnation assessed, the staff r
concludest thap the display of hydrogen concentration within the Safety Paramater Display System is needed to allow a user of the T
(
display to adequately evaluate the status of containment 4
conditions during a' severe accident. Also, key operator actions stated in the Emergency Response Guidelines are dependent upon the value of hydrogen concentration. For example, operator t
initiation of hydrogen recombiners and decisions whether to vent b
/
L M.
L g_.
a
I 5-containment are considerations. currently in the Emergency Response Guidelines.
L C.
HUMAN FACTORS PROGRAM In the additional information provided to the staff by PG&E, they committed to perform a human factors review of the SPDS.
In addition, they committed to expand this review to include the l
seventeen, display formats developed to further aid the operator.
The review will be conducted as part of the ongoing Control Room 1
Design Review and will specifically address the potential human engineering discrepancies identified in the staff's SER. As these additional display formats contain relevant SPDS data, the staff finds this commitnent acceptable and recommends that resolutions of these human engineering discrepancies be identified and reported in the Summary Report for the Detailed Control Room Design Review.
In addition, we recommend that the humanfackorsreviewoftheadditionaldisplayformats specificaT1y evaluate operator access to and the functional integration of relevant SPDS data.
IV.
CONCLUSIONS Based on our review of additional information provided by PG&E, we conclude:
D
- -~~
-=.,-,,-m
,% em ewm.
.m-e.--
%m...
7' );
~
. g.
2 6-b l j'
'f,
1.
The SPDS contains all but one of the parameters recomended
\\
by the staff. The missing parameter is hydrogen concentration in containment. Since hydrogen concentration is an important symptom of a severe accident, it should be displayed in the SPDS. To achieve this goal, we recomend the following condition be made a part of the license:
The licensee shall display containment hydrogen concentration as a parameter within the SPDS prior to startup after the first refueling outage.
-r l
2.
The human factors review of the SPDS and of the seventeen additional display formats within the ongoing Control Room Design Review is acceptable to the staff. We recommend that the results from this review be presented in the Summary Report for the Control Room Design Review.
W-*-*
916t gams
-se, p,9gege+
pgg w -
- _4-
l V.
REFERENCES 1.
U.S. Nuclear Regulatory Commission, " Clarification of TMI Action Plan Requirements, Requirements for Emergency Response Capability," U.S.
NRC Report NUREG-0737, Supplement No.1, January 1983.
2.
Letter from J. O. Schuyler, Pacific Gas and Electric Company; to G. W. Knighton, NRC; Subject, "SPDS Safety Analysis - Additional Information," dated September 4,1984.
3.
Letter from G. W. Knighton, NRC, to J. O. Schuyler, Pacific Gas and i
Electric Company; Subject, " Safety Parameter Displ6y System," dated June 27, 1984, with enclosure: "SPDS Safety Evaluation "
4 Letter from D. G. Eisenhut, NRC; to ALL OPERATING REACTOR LICENSEES, APPLICANTS FOR AN OPERATING LICENSE AND HOLDERS OF CONSTRUCTION PERMITS FOR WESTINGHOUSE PRESSURIZED WATER REACTORS; Subject, "Safet Evaluation of ' Emergency Response Guidelines' (Generic Letter 83-22)y "
dated June 3, 1983.
N'