ML20066J727
| ML20066J727 | |
| Person / Time | |
|---|---|
| Site: | Byron, Braidwood  |
| Issue date: | 02/22/1991 |
| From: | Schuster T COMMONWEALTH EDISON CO. |
| To: | Murley T NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), Office of Nuclear Reactor Regulation |
| References | |
| TAC-63249, TAC-64028, NUDOCS 9102260359 | |
| Download: ML20066J727 (5) | |
Text
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) 1400 Opus Place C:mmonwealth Edis:n
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j Down::rs Grove, Illinois 60515
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February 22, 1991 Dr. Thomas E. Murley, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555 Attn: Document Control Desk
Subject:
Byron Station Units I and 2 Braidwood Station Units 1 and 2 DCRDR Implementation NRC_DncheLlio n._5M 51L455_ L50-45fi/L452
Reference:
(a) Byron TAC #63249 & Braidwood TAC #64028
Dear Dr. Hurley,
All Detailed Control Room Design Review (DCRDR) modifications have been completed for Byron Units I and 2 (TAC #63249).
Byron Unit 1 DCRDR modifications were. completed by March 1, 1990. Byron Unit 2 DCRDR lifications were completed by November 21, 1990.
Braldwood Unit 1 DCRDR modifications (TAC #64028) are expected to be completed in the late spring of 1991.
Braidwood Unit 2 DCRDR modifications are expected to be completed in late 1991.
A letter confirming completion will be issued at that time.
This letter also serves to summarize the Byron and Braldwood DCRDR Human Engineering Discrepancies (HEDs) for which a change in the Implementation Classification commitment has been recommended by the Commonwealth Edison l
Human Factors Group.
The final status of nineteen HEDs, which vary in Byron and Braidwood applicability, are provided for NRC staff review in the enclosure of this letter.
Contingent upon NRC staff acceptance of the HED changes, DCRDR implementation may be considered completed for Byron Units I and 2.
Please direct any questions regarding this matter to this office.
Respectfully, Terence K. Schust Huclear Licensing Administrator TKS/rg Enclosure l
cc:
A.H. Hsia - NRR R. Pulsifer - NRR l
I i
Resident Inspector - Byron Resident Inspector - Braldwood A. Bert Davis l
ZNLD/651:9 9102260359 910222 2f;k99 5 "
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Page 1.of-t ENCLOSURE'
.L DCRDR CHANGES
-HEDs COMION TO BYRON AND BRAIDN000 RED E This.HED identified.the four flux recorders on the.PH05] panel as unused and-therefore' unnecessary. LThey were to be removed by the end of the Second Refueling Outage (2R',).
Subsequent station input indicated the recorders were used to provide indication of reactivity fluctuations =across the core _and were important in their current location.
The Human Factors Group supported an HED recommendation change to Accept-As-Is.
REDS 176. 3EH_and.470 These HEDs dealt with a lack of spatial correspondence between the Train A and' B Centrifugal Charging Pumps control switches and their associated miniflow valve control switches.
The HEDs were3 determined to be erroneous in subsequent > evaluation-and the Human factors. Group supported an HED recommendation change to AcceDt-As-Is.
HEDs 307 and 364
.These HEDs concerned the lack of Number 2-RCP Seal Leakoff Flow indication in the control room.
Indication was to be_provided by the close of the 2RO.
Although Flow-indication doesn't exist, alarm indication-does exist for high leakrate flow from the #2 seals, and low flow can be deduced from other seal alarms-This 1s adequate indication.to determine whether a loop's Reactor Coolant Pump has.leakrate flow from the #2 seals within the proper range to start the-pump, especially.during a transient situation.
Given that the alarm indications,are'available and that financial:and exposure dose rate costs would-be ver;y high, it is not cost effective,to install flow rate indication for a: low probability transient event.. The-Human Factors Group-therefore:
i supported an HED recommendation change to Accept-As-Is after interviewing operations; personnel.-
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HEDs 349 and 4011 These HEDs. concerned zone banding on the MCB indicator cover plates.
The
-commitment was to paint' zone colors directly on the meter faces.
Station
- Operations and Technical Staff personnel felt the corrective action to.be non u
cost effective.
Each indicator affected would-have to be removed from the paneliand.its associated system / subsystem taken Out-0f-Service, disassembled-from_the rear, reassembled after painting, reinstalled in the panel, had undergo a Return-To-Service test.- Moreover, without returning the indicator
-to_the manufacturer.for disassembly and assembly the component warranty would be voided.
The current transparent tape approach to zone banding has served the function well for years, and is easy to modify as operating conditions warrant. Operations has implemented a procedure to survey the zone bands for physical condition and accuracy in order to address the Human Factors: concern of the tape fiaying and/or becoming dislodped over time.
Human Factors reviewed and evaluated the condition of the zone banding tape at each station and found them satisfactory.
The Human Factors Group supported an HED recommendation change to Accept-As-Is.
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I Page 2 of 4 ENCLOSURE - CONTIllVED-i
.c HLDAL4 This HED was concerned with the Pressurizer Relief Tank "PRT PRESS HIGH" alarm setpoint.
It wasLfelt t.ufficient time was not available after alarm actuation to permit operators to take effective remedial action. -Subsequent investigations Indicated that no additional response time could be achieved
'wlthout significant angineering modifications.
Further,-PRT pressure;is typically controlled by draining the tank, an alternate and effective operating practico.
Human Factors supported a recommendation to change the Implementation to " Accept-As-Is".
HED.33fi
,This HED concerned the audible distinguishability between'the two RM-11
. Radiation monitors console alarms for Unit 1 and Unit 2.
The RM-11 consoles,
- though_ unit specific, actually display the status of a common parameter, that of--the status of all Unit 1, 2 and common Process and Area Radiation monitors.
Consequently, it is immaterial which unit _" responds" to the alarm first.
Both unit operators are required to be cognizant of radiation status plant _ wide, and both will respond to an alarm.
Since there is-no need to
' distinguish between monitors the HEDs have been closed as " Accept-As-Is".
HED_5.01 This'HED would have' reinstated alarms for Tempering Line Low flow on the PH04J-Feedwater/ Steam Generator panel, These alarms had existed at the panel at initial criticality.
During the engineering review associated with the
' modification to reinstall these alarms, it was discovered that the function of adjusting Tempering Line flow was to maintain an above ambient temperature at the Steam Generator upper feedwater nozzle, The specific Tempering Line flowrate. varies ~with reactor power level.
Engineering suggested that the low
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flow-alarms would not-be appropriate because temperature, as opposed to flow.
-is the1 critical parameter to be monitored.- Upper nozzle temperature is
-already. monitored by the process computer. A Tempering Line Low flow alarm setpoint predicated upon high reactor power levels would be a nuisance alarm at lowcpower operations.
The Human factors group concurred with the engineering synopsis from a function allocation perspective and changed the HED status to Accept-As-Is.
HED 54Q.
This HED concerned the display of static information with-the color Yellow on--
the:RM-11 Radiation monitor CRTs and some plant Process Computer displays,
-specifically the-Prodigy Trend displays.
The color graphics' hardware system t
-used at Byron and Braidwood Stations is capable of producing eight--colors;-
black,Jwhite, red, green, yellow, dark blue, cyan, and magenta.
Black is
. reserved for the background; Red is reserved for danger / alarm / warning situations;tDark. Blue and Magenta do not contrast well with the black background,.are consequently difficult to.see and are therefore infrequently used.
This'1 eaves only four colors with which displays can be built.
Occasionally yellow and green must be used to highlight and display static objects because of the diversity and complexity of the information-displayed.
These were documented as acceptable uses for the colors in the Color Use Matrix chart response to Open Item 4 in the "Braldwood Safety Evaluation
. Report Supplement 4, Section'18 Response" submitted to the NRC in July 1987.
The Human Factors Group has recommended Accept-As-Is status.
LZNLD/651:11
Page 3.ofl4; ENCLOSURE - CONTINUED u.-
HEDs UNIQUE TO BYRON
. HEDs 240 an(L433
,TheseLHEDs concerned auditory levels.
HED 240 identified a number of alarms 3
that~were not within +/- 2.5 db of the average of cil signals.
HED 438 was concerned with low PA system speaker volume in-the control room.. Auditory levels for both the annunciators and the PA speakers were set to
. specifications.
Subsequently Operations personnel adjusted the levels to-suit their own preferences.
Generally the adjustment was to lower the sound
--level. -'T_he Human Factors Group evaluated the settings as they had been.
adjusted and found them slightly low but still detectable and. acceptable.
The Human Factors Group therefore recommended these HEDs_be closed as
" Accept-As-Is";
HED'410-This HED concerned the potential for accidental control. switch actuation by Ltraffic into and out of the primary operating. area at the ends of the main control panel horseshoe.
Guardrails were-to be installed to minimize this potential;.
Since the conduct of the DCRDR the process of control-room access-has been procedurally modified.
Personnel desiring access to the control room
'must now obtain verbal-' permission from the Shift Control _ Room Engineer (SCRE) whose duty station 1s the Center Desk.
Personnel desiring access to a Unit's
. primary operating area must subsequently obtain verbal permission from the
. Unit operator. Asta result, traffic patterns have been altered and entrance into or egress from the primary _ operating area _via the horseshoe ends-1s no longer permitted except at the discretion of the Unit operator.
Human factors
- considers this procedural control to be-a satisfactory means of minimizing the potentialifor~ inadvertent control switch actuation at the ends of the
. horseshoe p'anel. ;Braidwood still. intends'to implement the criginal' corrective Laction of?t_nstalling1guardrails.
Byron opted to_ procedurally control access.
Lrather thanEinstall guardral_ls.
These approaches are acceptable and the-Human Factors-Group hasJmade.a recommendation change to allow either. approach to a
ifulfili the commitment.
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Page 4 of 4-
'i ENCLOSURE - CONTINUED HEDs UNIQUE TO BRAIDWOOD HED 217 This HED concerned correctly labeling an exhaust damper control switch on the
'0PH02J panel.
However, before the label was fabricated and installed, the switch was removed from the panel.
Since a label is no longer necessary, Human Factors Group recommended that removal of the exhaust damper switch _was-an appropriate corrective action for this HED.
. RED 317 This HED concerned displays that had values to either end of a zero (0) midpoint without having an indicant of which side was positive / negative or
.in/out..Two components'are listed (Main Generator 1, Output VARS, IVI-MP006 7and Voltage Regulator, IEl-MP022) as needing a label on-the meter face which indicates either a positive and negative or an "IN" and "OUT".
The Hain
-Generator component presently depicts "IN" and "OUT" on the meter face, while the Exciter Voltage Regulator meter does not require a positive and negative indication since it gives a deviation' reading on_either side of zero.
Therefore, corrections to these two meters are considered unnecessary and the'
-HED status.has been_ changed toL" Accept-As-Is".
-HED 477 This1HED described the desirability of having a start /stop control switch in lthe control room for the fire pumps.to eliminate.the_need to dispatch.an Equipment Operator (E0) to the Lake-Screen. house to accomplish those functions. 'This commitnant was made to the NRC in the FSR.
Subsequent to the-DCRDR review the autofstart feature of the pumps was improved significantly
- reducing the--time criticality of dispatching the E0.
Moreover, a-review of-NFPA' Code 20 indicated that a-remote stop switch would be contrary to. code and.
therefore would be prohibited. The Human Factors Group-concurs with a
. petition to modify the original response to " Accept-As-Is".
HED 552
- This HED concerned switch positionLlabels-for the Pressurizer PORV controls on the PH05] panels.
The control notches'did not correspond exactly with the switch: positions as labeled.
Subsequent Human Factors evaluation determined the-deviation magnitude did not warrant any further corrective action, and hence.a changelin status'was made to " Accept-As-Is".
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