ML19350B854
| ML19350B854 | |
| Person / Time | |
|---|---|
| Site: | Zion File:ZionSolutions icon.png |
| Issue date: | 03/13/1981 |
| From: | Tramm T COMMONWEALTH EDISON CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML19350B855 | List: |
| References | |
| 1154B, NUDOCS 8103230886 | |
| Download: ML19350B854 (6) | |
Text
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' T*N Commonwealth Edison
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O7 Accress Reciy to Post Cice Box 767 (y' CNeago, mine:s 60690 g % '_[ _
Maren 13, 1981 y
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Mr. Harold R.
Denton, Director Office of Nuclear Reactor Regulation
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U.S. Nucle.ar P agulatory Commission g
Wasnington, D 20555 T-
Subject:
Zion Station Units 1 ano 2 Reset of Engineerec Safety Features NRC Occket Nos. 50-295 anc 50-304 Reference (a):
October 15, 1980 letter from W.
F.
Naughton to H.
R.
Denton.
Dear Mr. Denton:
Tnis is to prosice accitional information requested oy tne NRC staff regarcing the review of oypass anc reset of engineerec safety features at Zion.
Attachment A to this letter contains the information whicn was transmittec by telepnone on Decemoer 4,
1980.
One (1) original and thirty-nine (39) copies of this letter are ceing sent.
Eight copies of the referenced crawings are also being sent.
Please accress further questions regarding tnis matter to this office.
l l
Very truly yours, i
ffh:^^
T. R.
Tramm Nuclear Licensing Acministrator Pressurizec Water Reacters l
l cc:
Resident Inspector - Zion Bill Kountanis, EG&G Eiwd b' i
se-o naA- ~f i
sc ec p [utd
- h Chs 11548
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[ ' 'N Commonwealth Edison
) one First Nat:onal Plaza. Crucago lilinoe
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Address Reply tct Post Offree Box 767 ms q
Chicago. filinois 60690 1
March 13, 1981
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6 Mr. Harold R. Denton, Director D7)?j 9g
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Office of Nuclear Reactor Regulation L-, #'4 7
U.S. Nuclear Regulatory Commission k
"r 46 Washington, DC~ 20555
Subject:
Zion Station Units 1 and 2 q
Reset of Engineered Safety Features NRC Docket Nos. 50-295 and 50-304 Reference (a):
October 15, 1980 letter from W.
F.
Naughton to H.
R. Denton.
Dear Mr. Denton:
This is to provide additional information requested by the NRC staff regarding the review of bypass and reset of engineered safety features at Zion.
Attachment A to this letter contains the information which was transmitted by telephone on December 4, 1980.
One (1) original and thirty-nine (39) copies of this letter are being sent.
Eight copies of the referenced drawings are also
-being sent.
Please adoress further qv" clons regarding this matter to this office.
Very truly yours, ffht^: _ -
T. R.
Tramm Nuclear Licensing Administrator Pressurized Water Reactors cc:
Resident Inspector - Zion
~ Bill Kountanis, EG&G 1154B 2
Attachment A Additional Information on Bypass and Reset of Engir.eered Safety Features at Zion Station I.
System Description - Containment Monitoring (New System)
Reference:
NUS Corp. Drwg. 5307M3006, Rev. 1, 12-5-80.
This new containment radiation monitoring system will consist of the following subsystems; containment post accident sampling and containment air monitoring system.
Containment Post Accident Sampling This system will be available for " grab sampling" of the containment atmosphere subsequent to the NRC postulated accident.
Containment Air Monitoring This system consists of an Eberline SPING 4 gaseous radiation monitor capable of independently measuring particulates, iodine, and gases in the low, medium, and high range.
This system is designed non-safety related and equipment is not presently qualified environmentally or seismically.
- However, the Eberline manufacturer is conducting seismic evaluatiuns on this equipment.
Results are predicted to be available in mio-1981.
Tnis system is designed to be used during normal plant operations.
During " post accident" conditions this system will-be isolated and the post accident system will be available for-use.
High gaseous radiation within the containment will be initially i
detected by the agross gamma detector" which is an Eberline manufactured piece of equipment separated from the basic Eberline skid.
This detector is isolated so that the basic Eberline equipment will not be degraded by the post accident high radiation. ~Upon indication'of high radiation in containment ' by this detector,. automatic closure of the purge valves will occur.
For normal operations, upstream of the Eberline equipment, a
moisture separator / air dryer wi'll be provided to protect the
-monitoring equipment from excessive moisture in'the containment samples.
The~ Unit 1 and Unit 2 monitors will be located in the fuel handling building on the roof of the change / shower room.
There-are no high energy-lines in this area.
s
. The control sequence of this system is being designed such that upon indication of high radiation from any of the radiation monitoring channels, automatic closure of the purge valves will Resetting of the purge valves can be initiated manually occur.
only if no high radiation exists.
For " grab sampling" of containment subsequent to the accident, sample line valves will open and the post accident sample system will be placed in service.
The Eberline equipment.will not be used for this function. -The control sequence will be designeo such that when sampling valves are opened during post accident conditions, isolation of the purge valves will not be effected.
II.
System Description - Containment Monitoring (Existing System)
The containment gaseous radiation monitoring system was originally designed non-safety reldted.
The existing radiation monitoring equipment is not environmentally or seismically qualified.
This equipment is located in both Unit 1 and Unit 2 containment access corridors.
There are no high energy lines located in these areas.
This Westinghouse-designed radiation monitor does not incorporate specific equipment for control of high moisture since sample line flow velocities are sufficiently large enough to preclude moisture condensation.
- The control sequence for this system is designed such that.upon indication of high radiation the purge valve closes.
There is
+
a switch.in the control room for reset.
Reset may only be
'acceptea upon clearing of the radiation monitor.
Sample line valves _are isolated from containment isolation signal.
III. System Description - Control Room HVAC Radiation Monitoring (New System)
Reference:
FSAR Drwg. 9.10.2-l and Proposed FSAR revisions to pages 9.10-12 and 9.10-14.
.The inlet air supply to the control room HVAC equipment is available from~two sources.
For normal oper~ation outside air is..supplieu.to the HVAC equipment.
This outside air is continuously monitored by an-Eberline SPING 3 radiation monitor which~ independently. measures particulates, iodine, and gases in:
the' low and medium range.
Indicationfor radiation from any,of these channels will.cause isolation of this supplied-air.
The control sequence is designed.such that. air will then be 1
supplied from the turbine building.
One of two.make-up filter fans will'be started andisupply air will be routed through the make-up air charcoal filter unit to the control room HVAC equipment.
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' System Description - Control Room HVAC Radiation Monitoring (Existing System)
The inlet air supply to the control room HVAC equipment ava11a01e from two sources.
is is supplied to the HVAC equinment.For normal operation outside air This outside air is continuously monitored by an NMC radiation monitor whicn measures particulates and gases.
Indication of radiation on this monitor will cause isolation of this supplied air.
control sequence is designed such that air will The then be supplied from the-turbine builuing.
-supply will be through a non-filtered source.This preliminary turbine There is a second NMC radiation monitor in the turbine Duilding air supply that continuously monitors this air source, then routed through a charcoal filter unit. the supply air is There is a switch in the control room for reset.
clearing of the radiation monitor. Reset may only be accepted upon
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s' botrds ir.to a return duct system which is connected to outlets on top of the boards.
The re tu rn 2ir is r:!xed with outside air as required to meet ninimum ventilation require. nts and/or room cooling requirenents.
The control room HVAC syst.e= eqt pter.: room and outside an intake is located at E1.617'-
0".
A fixed mini =us quantity of outside air is supplied which is suf ficient to maintain a positive operating pressure in the control room with respect to adjacent areas to prevent inl e akage'.
The system will be controlled to maintain a nominal 75*F and 40% RH.
The outside air supply is brought in' through a missile protected wall opening.
In the event of high radiation detection in the outside air supply, the noncal outside air inlet is elecad, the emergency =ake-up filter fan is automatically started,and make-up air from the turbine building is introduced through l1 a HEPA filter and charcoal filter for the removal of potential radioactive con t araination.
In all other respects, the system operates as for normal operation.
In the event of seoke in the control boards, smoke detectors will annunciate Concurrently, all of the supply air del'ivered to the in the control room.
conditioned spaces will pass through a nor: ally bypassed charcoal filter for smoke and odor absorption.
Mechanical cooling for the control room system is provided by means of two (2) 100% capacity water-cooled refrigeration units.
Each refrigeration unit will be connected to its respective air _ handling unit.
Each air conditioning system has a local control panel and each is independent 1p controlled.
Important operating functions are controlled and monitored from the main' control room.
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9.10-12 s
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fro: the remainder of the auxiliary butiding.
The control roc = has two (2),
100% capacity HVAC syste=s together with adequate shielding which is independent frc= the H"AC syste= for the retainder of the intercennecting areas.
All E"AC equip =ent for the control roc = has the neces ary standby capacity to acco==odate an equip =ent faflure and is pcvered frc= the e=ergency electrical syste= so that adequate ventilatica is =aintained at all ti=es.
Fresh Air Intake A radiaticn =cnitor i= the cutside air intake is set to sense an abacr=al level of activity.
On an increase in activity approxinately 100 tines cheve background, the HVAC syste= automatically starts cne (1) of two (2) 100%
capacity c=ergency filter =ake-up air fans and routes the =ake-up air frc= the turbine Suilding
^
through two (2) HEPA filter and charccal filters arranged in series.
The
=ininu= quantity of outdoor air introduced into the syste= under all conditions replaces air Icakage for syste= pressurizing.
The quantity of
=ake-up air to the control reca ii = ore than sufficient to satisfy persennel requirements.
In all other respects, the syste= operates as for nor=al ope ration.
~
A pressure differential controller with sensing ele =ents in the centrol roc = and the auxiliary and turbine buildings modulates a centrol da=per in the relief duct to =aintain a positive pressure within the control rec =.
This will prevent the inleakage of any airborne activity frc= outside the control room area.
All cable, piping and =iscellaneous penetraticas through the biological barrier are scaled to =inimize the tagnitude of leakage.
Personnel decrs will be tight-fitting cad gasketed.
Fire /S=oke Detection and Centrol
~
An cquip=a=: fire in the control roc = will :: c2 usa aband:n=2nt si the centrol roo= and vill not prevent a safe shutdown of the plant.
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9.10-14
,