ML20084B976
| ML20084B976 | |
| Person / Time | |
|---|---|
| Site: | Fermi  |
| Issue date: | 04/18/1984 |
| From: | Jens W DETROIT EDISON CO. |
| To: | Youngblood B Office of Nuclear Reactor Regulation |
| References | |
| RTR-NUREG-0737, RTR-NUREG-737 EF2---67-808, GL-82-33, NUDOCS 8404270003 | |
| Download: ML20084B976 (8) | |
Text
Wayn1 H. Jrru isar atons Deholt Edison RPG?!=-
April 18, 1984 EF2 - 67,808 Director of Nuclear Reactor Regulation Attention:
Mr.
B. J.
Youngblood, Chief Licensing Branch No. 1 Division of Licensing U. S. Nuclear Regulatory Commission Washington, D. C.
20555
Dear Mr. Youngblood:
Reference:
(1)
Fermi-2 NRC Docket No. 50-341 (2)
- Letter, D. Eisenhut to all Licensees and Applicants for Operating Licenses,
" Supplement 1 to NUREG-0737 - Requirements for Emergency Response Capability (Generic Letter 82-33)", dated December 17, 1982 (3)
Letter, H. Tauber to B. J. Youngblood,
" Response to Supplement 1 of NUREG-0737",
dated April 15, 1983
Subject:
Safety Parameter Display System (SPDS) Safety-Analysis This letter transmits the SPDS safety analysis for Fermi-2.
This analysis provides.the documentation required in Section 4.2.a of Reference (2) and is submitted for NRC review in accordance with the schedule provided on Page 7 of Reference (3).
If you have any questions regarding the enclosed safety analysis, please contact Mr.~ 0. Keener Earle, (313) 586-4211.
Sincerely, s'
/
cc:
Mr. P. M. Byron Mr. M. D. Lynch 8404270003 840418 R
00>
PDR ADOCK 05000341 1
J'_
PDR _
u
Enclosure EF2-67808 SPDS Safety Analysis (Parameter Selection)
NUREG-0737, Sopplement 1 One of the many modifications recommended as an aftermath of Three Mile Island (TMI-2) was the addition of a Safety Para-meter Display System (SPDS) in the control room.
Industry and NRC reports generally describe the SPDS as a concise display of important plant parameters to aid operating personnel in the assessment of abnormal conditions.
Recent NRC guidance on SPDS is contained in Supplement 1 to NUREG-0737 and is interpreted as being the prevailing guidance if inconsistencies exist with other documents.
Supplement 1 to Nt; REG-0737 provides guidance on emergency response capabilitiestwith Section 4 specifically addressing SPDS.
Section 4.2.a requests licensees submit a written safety analysis describing the basis on which the selected parameters are deemed sufficient to assess the safety status of each of the identified functions.
The purpose of the following analysis is to satisfy this NRC requirement.
REFERENCES 1.
NUREG-0737, " Clarification of TMI Action Plan Requirements."
2.
NUREG-0696, " Functional Criteria for Emergency Response Facilities" 3.
NUREG-0737, Supplement 1, " Requirements for Emergency Response Capability" 4.
Letter frc.d 11. Tauber (Detroit Edison) to B.
Youngblood (NRC), " Response to Supplement 1 to~NUREG-0737", dated April 15, 1983 5.
HUREG-0835 (Draft), "lluman Factors Revieu Guidelines for Safety Parameter ' Display Systems, ~ Draf t.
6.
Letter from T. Dente - (BWR. Owners ' - Group) to D. ~Eisenhut (NRC), "NEDO-24934,. Emergency -Procedure Guidelines, BWR 1/6, Revision 2",
dated June 1, 1982 7.
Letter from D. Eisenhut (NRC).to T.
Dente (BWR-Owners'
~
Group), " Safety. Evaluation Report on Emergency. Procedure Guidelines, Revision 2, NEDO-24934, June 1982", dated
- February 4, 1983.
8.
NUREG-0798, Supplement 1, " Safety Evaluation Report for Fermi-2",. Docket 50-341 9.
ALO-1003, "BWR Graphic Display Sy. item Dynamic Screening Program", printed February 1982 i
'nclosure E
EF2-67808 Page-2 10.
ALO-1019, " Simulator Evaluation of Boiling Water Reactor Owners' Group (BWROG) Graphic Display System (GDS)",
printed May 1983 11.
NSAC-21, " Fundamental Safety Parameter Set for Boiling Water Reactors", December 1980 SPDS PURPOSE The purpose of the SPDS is to be an operator aid.
The SPDS provides a concise display of critical plant variables to control room personnel to aid them in rapidly and reliably determining the safety status of the plant.
The SPDS has the capability to provide:
associated parameters on a single display; variable versus variable plots for emergency operating procedure limit curves; provide trending; and provide other features that complement the existing control room information available to the operator. However, the SPDS provides information only and it is intended that the operator confirm readings with existing contrul room instrumentation.
CRITICAL SAFETY FUNCTIONS / PARAMETER SELECTION The SPDS monitors plant parameters or derived variables representative of the safety status of the plant.
The para mete rs for the SPDS were selected based on industry guidance which identified critical safety functions and parameters which should be monitored, and a multi-discipline Fermi-2 group review of SPDS displays.
The Fermi 2 SPDS is based on the Graphic Display System (GDS) developed by the BWR Owner's Group Control Room Improvement Committee.
The GDS display format contains critical safety functions for reactivity, core cooling, reactor coolant system integrity, containment system integrity and radioactive effluent to the environment.
These safety functions parallel industry guidance such as NUREG-0696, NSAC-21 and Supplement 1 to NUREG-0737 which states:
"4.2.f.
The minimum information to be provided shall be sufficient to provide information to plant operations about:
(i)
Reactivity control (ii) Reactor core cooling and heat removal from primary system.
(iii) Reactor coolant system integrity (iv) Radioactivity control (v)
Containment conditions The specific parameters to be displayed shall be determined by the licensee."
Enclosure EF2-67808 Page 3 The primary variables which address industry guidance are identified below.
a.
Reactivity.
The primary variables used to monitor reactivity are provided by existing neutron monitoring instrumentation.
APRMs provide data on reacto.r power and SRMs monitor subcriticality.
b.
Core cooling.
The primary variable used to monitor core cooling is reactor water level as provided by existing level instrumentation.
Table 1 identifies the various level instruments used to monitor vessel level.
Another SPDS parameter which may be used to complement the water level information for assessment of core cooling is RPV pressure data.
c.
Reactor coolant system integrity.
This parameter is assessed by monitoring reactor pressure, drywell pressure, drywell floor drain sump level, and RPV isolation.
In addition, radiation monitors identified in Table 1, and used to support other SPDS displays, may be used to determine the integrity of the reactor coolant system.
d.
Containment integrity.
This parameter is asse ased by measuring drywe.il e.nd torus pressure, containment isolation status, combustible gas level, suppression pool temperature, torus level and drywell temperature.
e.
Radioactivity effluent to environment.
This para-meter is assessed by monitoring the radioactivity at planned plant release points.
Table 1 identifies radiation monitors which relate information on radia-tion levels within the plant structures (e.g.,
containment, reactor building).
Table 1 provides a list of parameters associated with the Fermi 2 SPDS.
Emergency Procedure Guidelines (EPGs) have been developed by the BWR Owner's Group and have been submitted to and reviewed by the NRC (References 6 and 7).
The EPGs are sympton based and are provided to improve the operators ability to mitigate the consequences of a broad range of initiating events and subsequent multiple operator errors.
The Fermi 2 Emergency Operating Procedures (EOPs) were based on the EPCs and have been deemed adequate by the NRC (Item I.C.8 of Reference 8).
The EOPs identify entry conditions and contain parameter versus parameter limit curves. 'The SPDS includes the EOP limit curves and parameter information which is supportive of determining entry conditions.
The SPDS displays are comprised of an overview display, criti-cal safety function displays (generally a bar and/or trend) and
Enclosure EF2-67808 Page 4 the EOP limit curves.
The proposed SPDS displays were reviewed by a multi-discipline group composed of persons knowledgeable in the areas of system design, human factors, instrumentation and operations.
Typical display formats for an EOP limit curve and bar chart are being incorporated into the Fermi 2 PSAR (Item H.III.A.l.2, Upgrade Emergency Support Facilities).
DESIGU ANALYSIS The graphics provided to the operator by the SPDS are one of the man-machine interfaces to a computer based data acquisi-tion, processing and display system.
The system acquires both digital and analog inputs from field sensors and computer data links with monitoring and control systems throughout the plant.
System design features for reliability, signal isolation, seismic requirements, signal validation and human factors have been incorporated, as discussed below, to ensure the goal of SPDS in assisting the operator.
The SPDS function is intended to be highly reliable.
A dual computer system has been designed with automatic throwover for various conditions. Uninterruptible power has been provided to components essential to the operation of the computer system.
The computer room air conditioning system has been redesigned to enhance the reliability of the computer system.
Spare parts inventories have been provided and plant personnel have been trained to maintain the hardware and software of the system.
Existing signal loops of monitoring and control systems were tapped to provide inputs for the SPDS.
The isolation require-ment for analog safety-related circuits.-was provided by using a qualified modulator isolator for each circuit and a demodulator card in the data acquisition system.
Dry contact inputs were provided for digital inputs. Additionally, computer links have been provided to other plant data systems.
Engineering has been completed in accordance with applicable design criteria to ensure that the SPDS cannot adversely affect safety-related systems.
The requirements for the SPDS do not include seismic qualifica-tion.
However, the structural integrity and mountings for the cabinets in the relay and computer rooms and the display generators / terminals in the control room operator console have been evaluated to ensure they do not adversely affect safety-related components in a sesmic event.
Signals for tlue SPDS are processed and validated to prevent
-misleading the operator.
Redundant input signals are used for selected parameters and comparison limits are performed for validation.
Additional information. processing is performed for analog, digital.and derived parameters and-include the following:
inclosure EF2-67808 Page 5 o
Sensor range limit checks o
Conversion to engineering units o
Validation routine processing o
On-line diagnostics for transmission o
Time tagging of data Factory performance tests were conducted to validate the SPDS.
These tests were completed at the vendor's facilities before shipment to the Fermi 2 site.
The site acceptance testing includes repetition of many of these factory performance tests and validation of the SPDS system from field sensors to display.
The SPDS design incorporates human factors engineering gui-dance.
The operator's interface with the displays and keyboard have been designed to provide easily accessed and readily understood displays.
The BWR Owner's Group Control Room Improvements Committee developed the initial Graphic Display System (GDS) in a program which had extensive human factors evaluation.
The program included development and dynamic screening of the GDS and later T simulator evaluation of the displays by operators.
The dynamic screening and simulator evaluation are discussed in references 9 and 10, respectively.
The Fermi 2 SPDS includes many features of th2 GDS, and has incorporated most of the recommendations from the findings of the simulator evaluation.
Some of the human factors criteria which were considered in the SPDS design were:
o Use of color, shape, size and location of coding o
Single stroke key access of displays o
Grouping by function o
Protection / Authorization of changes o
La beling, scaling and readability o
User review of displays o
Scan rate of inputs o
Response time to requests o
Development of a User's manual o
Minimization of reflection and glare o
Selection of font o
Data presentation formats o
Screen layout
SUMMARY
The Fermi 2 SPDS has been designed with a cognizance of industry and NRC guidance and represents a substantial good faith effort to meet the criteria of Supplement 1 to NUREG-0737.
SPDS design requirements with regard to parameter selection, isolation, signal validation and human factors engineering have been analyzed.
The critical safety function
' Enclosure EF2-67808 Page 6 based, and EOP-related, selected parameters are sufficient to assess the st.fety status of the indentified functions for a wide range of events, which include symptoms of severe accidents.
The installation of SPDS does not represent an unreviewed safety question or a change to the draf t Fermi 2 Technical Specifications.
w
- ' Enclosure EF2-67.808 TABTE 1 Paraneters Associated With SPDS Displays Reactor Water Ievel Wide Rarge Div I Wide Rarge Div II thrrow Range Div I lbrrow Range Div II Ebel Zone Range Div I Fuel Zone Range Div II Shutdown Range Reactor Pressure Wide Range Div I Wide Range Div II Dome Pressure Wide Range Dome Pressure Narrow Range Neutron Monitoring APRM A SRM A APPM B SRM B APRM C SRM C APRM D SRM D APRM E APRM P Main Steam Line Radiation Containment High Range Rad Mon Div I Contairunent High Range Rad Mon Div II Drywell Pressure Wide Range Div I Wide Range Div II Narrow Range Div I Narrow Range Div II Prinary Containnent 02 Ievel Div I Primary Containment 02 Ievel Div II Torus Water Ievel Wide Rarge Suppression Pool Tepperature Drywell Temperature Fuel Pool Div I Rad Mon A Fuel Pool Div I Rad Mon C SJAE Radiation Mon A SJAE Radiation Mon B Drywell Floor Drain Staip Imvel Main Steam Line Isolation Valve Status Safety Relief Valve Status SGTS Exhaust Fan Div I Status SUPS Exhaust Fan Div II Status
'Ibrbine Bldg Exhaust Fan Status Radwaste Bldg Exhaust Fan Status Reactor Bldg Exhaust Fan Status Gaseous Effluent Radiation Monitors-SGIS Div I Exhaust SGTS Div II Exhaust Reactor Bldg Exhaust Radwaste Bldg Exhaust Turbine Bldg Exhaust d
m
.- m.
. -