ML19290E226
| ML19290E226 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 02/29/1980 |
| From: | Lundvall A BALTIMORE GAS & ELECTRIC CO. |
| To: | Reid R Office of Nuclear Reactor Regulation |
| References | |
| RTR-NUREG-0578, RTR-NUREG-578 NUDOCS 8003050499 | |
| Download: ML19290E226 (13) | |
Text
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BALTIMORE GAS AND ELECTRIC COMPANY P. O. B OX 147 5 B ALTIM OR E, M ARYLAN D 21203 ARTHUR E. LU N DVA LL, J R.
vect Pas siota.T s o.u Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D.C.
20555 Attn:
Mr. Robert W. Reid, Chief Operating Reactors Branch #h Division of Operating Reactors
Subject:
Calvert Cliffs Nuclear Power Plant Unit Nos. 1 & 2, Docket Nos. 50-317 & SC-318 Follow-up Actions Resulting from 'DfI-2 Incident (Lessons Learned)
Gentlemen:
' is our response to NRC questions raised during your visit to Calvert Cliffs on February 19, 1980, as required by your letter of February 20, 1930.
f Very,,truly. yours,
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.. to A. E. Lundvall letter of 2/29/80 Response to NRC questions on Lessons Learned Category A Items 2.1.3b Subcooline Meter Comment:
Complete installation of subcooling meters.
Response
All equipment for this modification was received as of 2/25 We intend to complete installation by 3/26.
2.1.h Containment Isr'ation Comment:
Provide the bases for classification of certain systems as essential or votentially beneficial in your 11/20/79 dis-cussion of systems not subject to automatic isolation. CEN-125 can be referenced for obvious essential systems. Plant unique justification should be provided for the other system in this category.
Response: Reference should be made to CEN-125, section 7.1 of the chapter on Containment Isolation, which provides the basis for the essential systems cited in our 11/20/79 discussion, except the containment pressure instrument lines classified by us as an essential fluid system penetrating the containment, but not so addressed in CEN-125 These penetrations are the impulse lines to the Reactor Protective and Engineered Safety Features Actuation System (ESFAS) nressure transmitters and as such should be allowed to continue to monitor containment pressure throughout any accident evolution rather than be automatically isolated.
Our 11/20/79 discussion cited the reactor coolant pump (RCP) cooling vater and instrument air into containment as "potentially beneficial" systems.
Even as such, these systems are isolated on high containment pressure via an ESFAS signal, in contrast to the essential systems which are not subject to automatic CIS/SIAS isolation. The basis for considering these lines as "notentially beneficial" is that their availability adds a measure of reliability and flexibility (and by extension safety) to accident response capability during an accident evolution which is not accompanied by a high containment pressure.
Potential benefits of these systems are as follows:
a.
Cooling Water to RCP's: Refer to the CEN-125 discussion of this system. Availability of RCP's adds an option to the means available for removal of heat from the RCS, improving versatility in accident recovery and control.
. b.
Instrument Air: Availability of instrument air to containment allows the following potentially beneficial functions which would not otherwise be available:
(1) Letdown initiation and control (2) Containment spray isolation (3) Pressurizer auxiliary spray (h) Safety injection control (pressure, venting, draining, filling)
(5) control of service water to containment coolers (6) Reactor coolant and containment atmosphere sampling (7) Quench tank drain and vent Co= ment: Describe those branches of the main steam line that are not automatically isolated and those parts of the main steam system that are automatically isolated. For the isolated branches, pro-vide the isolating parameters.
Response: Those main steam line branches not receiving an ESFAS automatic isolation signal are:
1.
Main steam to the auxiliary feed pump turbines and 2.
Main steam atmospheric dump lines.
The only main steam line branches which do receive an ESFAS automatic isolation signal are those branches dovn stream of the main stean isolation valves (MSIV's). The MSIV's close on a lov steam generator pressure signal, as do the small bypass valves used for varming the downstream piping system.
Co= ment: Document your procedures for valve reopening to address the staff's concern that your nodification to the isolation valve reset circuitry does not, assuming single failure, preclude the use of systems beneficial in mitigating an accident.
Response
In the event that any number of contacts in the circuit for the containment isolation reset permissive should not "make-up",
the appropriate procedure to follow to unisolate these valves is to: a) insure that the initiatir:g isolation parameters have returned below the isolation initiating levels; b) insure that the isolation valves' handsvitches are placed in their ESF position; and c) reset the containment isolation signal at the ESFAS cabinet itself.
. Comment:
The emergency operating procedures should be modified to include additional information to advise the operator of those isolation valves that must be in the " safe" position to form a reset per-missive and the crocedures to reopen notentially beneficial systems.
Response
The Emergency Operating Procedures vill be modified to annotate the ESFAS checklists to flag the " reset permissive" valve hand-switches. A caution vill be added to ensure that in the event a remote reset is uncuccessfully attempted, the handsvitches are re-checked prior to effecting a local reset from the ESFAS cabinets. The procedure change vill be implemented by 3/1h/80.
Comment: Complete modifications of the oxygen and the reactor coolant system sample valve control circuits.
Response
Equipment required for this modification was received as of 2/25 We intend to complete installation by 3/26.
2.1.6a Systems Interrity Comment:
Incorporate procedure to dump reactor coolant drain tank to con-tainment sump following an accident to assure that reactor coolant pumps can be operated without using the CVCS system or include CVCS and gaseous vaste system in leak reduction programs.
Response: The loss of coolant procedure vill be modified to ensure the Reactor Coolant Drain Tank is dumped to the containment sump to allow reactor coolant pumn cueration without reliance on the CVCS system.
The procedure change vill be implemented b'y 3/1h/80.
Comment:
Incorporate procedures for obtaining and analyzing plant effluents for radioiodines and particulates. Provide all the information re-quired in the October 30 letter.
(not including steam relief and dump valves)
R;sponse:
Radioiodines and particulates vill be determined in the same manner as in our existing procedure RCP-1-502.
This procedure, along with certain modifications due to high dose rate levels, vill be incorporated into RCP-1-503. The procedure change vill be implemented by 3/31/80.
Appendix A is a system description of the Radiation Monitoring System, and is intended to provide the information requested by your 10/30 letter.
2.2.lb Shift Technical Advisor Comment:
The staff vill check the acceptability of the proposed STA program involving the use of two (2) SRO's during cold shutdown conditions.
Response: None required.
h-2.2.2a Control Room Access Comment: Licensee must implement procedures which establish lines of manage-ment and communication between control room and the different emergency centers.
Response
The Site Emergency Plan Implementing Procedure describing the Technical Support Center vill be revised to show the lines of management and communication for the director of the center.
Functionally, the center director vill report to the Site Ener-gency Director and communicate laterally with the Shift Supervisor in support of plant operations. The procedure change vill be implemented by 3/14/80.
2.2.2b Technical Sunnort Center Comment:
Licensee must establish dedicated communications between TSC and CR, and TSC and Energency Operations Center.
Response: To support the ability to simulataneously communicate from the Technical Support Center to the Control Room and the Emergency Control Center, a second plant page unit has been added to the Technical Support Center.
Comment: Provide plant drawings and procedures etc. inside TSC.
Response: As the final equipment details for the long-term ungrading of Technical Supnort. Center (TSC) become available, efforts vill be made to allocate space for the Record Retrieval Center (RRC) in the Technical Sunport Center. Our best estimation at this time indicates that the location of the Record Retrieval Center (RRC) on the 55 foot elevation vould consume critical space better devoted to monitoring equipment and personnel work space.
However, we expect that the RRC could be located on the h5 foot elevation near the base of the stairway to the TSC, thereby eliminating the need to enter the Control Room to gain access to the records.
In finalizing the plans for the TSC, priority v111' be given to locating the RRC:
(1) in the TSC (55 foot ele-vation), or (2) on the h5 foot elevation of the " shop area".
2.1.8a Samnline Comment: Develop and implement procedure to obtain containment air sample with as-built system. The grab sample procedure can be used if containment air sampla station is inaccessible.
Response: RCP-1-503 vill be revised to allow for sampling of containment air by using the present system before using the "vorst case" method. This vill be accomplished by establishing " action levels" based on dose rate. The procedure change vill be implemented by 3/31/80.
2.1.8b Effluent Monitors Comment: Provide equipment and develop procedure for monitoring the plant vent, condensor air ejector (if not included in nlant vent) and steam safety relief and dump valves for noble gases if the existing equipment goes offseale. Provide all the information required in the October 30 letter for each monitor.
Response: The noble gas release rate vill be determined by means of a portable dose rate instrument.
Data vill be obtained to correlate the expected release rate with dose rate determinations at preselected points. These instruments will be maintained in the Control Room Emergency Kits for implementation.
Appendix A is a system description of the Radiation Monitoring System, and is intended to provide the information requested by your 10/30 letter.
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APPENDIX A CALVERT CLIUS u
RADIATION MONITORING SYSTEM
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PURPOSE is.
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The function of the Radiation Monitoring System is to provide plant operating personnel with an indication of radiation and radioactivity levels throughout the plant. The System monitors and records various plant paraneters and actuates both local and remote alares if an unsafe condition is being approached.
These audible and visual alarcs et.rve to warn operating personnel of an increasing ~ radiation level or abnormal radioactivity concentrations at various presclected points throughout the Reactor and Turbine Plant Systccs.
This warning system may indicate a system or corponent nalfunction which needs operator action or it ncy perform automatic protective actions to correct and/or isolate an abnornal condition to prevent an uncontrolled release of radioactive caterial to tha environcont.
II.
DESIGN The Radiation Monitoring System, hereaf ter referred to as the R.M.S.,
is designed to perform three (3) basic functions:
1.
Provide operating personnel with a varning of any potential radiation hazard which develops.
2.
Provide advance varning of a plant malfunction which could lead to a potential radiation hazard or to plant da= age.
3 Provide a varning of any pending inadvertent release of radioactivity to the environnent and automatically ter=-
inates the release from certain syste=s.
The basic functions are accomplished by the use of solid state, integrated
. electronic circuits with proven detcetors and detection techniques, which provide a high degree of reliability for monitoring radiation and radio-activity levels.
APPENDIX A CALVERT CLIWS H
RADIATION MONITORING SYSTHf I-Only three (3) types of printed circuit boards are employed in the
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entire system and these are completely interchangecble between channels and drcvers.
Two (2) different detectors are used, depending on cppli-cation, which are proven for reliability and responne under all expected types of use'.
This minimal ccaponent approach optimizes caintenance end YY
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spare part requirements.
ff Each individual component or subsection of the R.M.S. is designed to meet all current applicable A.S.T.M., A.N.S. I., N.E.M. A., A.S.M.E. and IEEE standards. The entire system sensitivity ensures that the require-ments of 10CFR20 can be cet.
III.
SYSTEM DESCRIPTION R.M.S. is actually a cocbination of sub systems which carry out the acale,n functicas cf the cc plete unit.
Ecch cub cytten 'e referrad to V
as a channel, and is a' complete unit in itself.
A typical active channel contains a detector with associated impedance netvork, a local indicator and alarm counted at or near the senpling point, a remote indicator and alarm in the control room, a computer indicator, a power supply, and controls. The computer indicator, pcVer supplies, remote alares, and controls are all located in a central con-trol console in the plant cont,rol room.
Using the building block r.ethod of construction, it is possible to expand or contract this standard desi;a system so that it is easily nolded to fit any plant requirement.
IV.
COMPONENT DESCRIPTION A.
Control Console 1C22
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A major portion of the control, conversion, and readout circuit 2'/
required in the R.M.S. is housed in a rack type cabinet designated O
4 O
APPENDIX A CALVERT CLIFFS w
RADIATION MONITORING SYSTEM 1
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as the Control Console.
This Control Console contains the control
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and indication circuits located in dual and single chne.nel assc=blics.
The Control Consolo also houses recorders, terninal boards, relay ascenblics, dual voltage power supplies, and all the interconnect-ion circuitry required.
The readout and control channels located on the racks are in pullout assc=blics mounted on slides, with a stop to prevent inadvertent total pullout.
Ribbon connectors between the rack and the panel connectors facilitates assc=bly pullout without interruption of circuits.
The drawer asscnblics are held in a closed position by locking devices intc6ral to the
' handles.
B.
Dual Channel Dravers The Dual Chrainel Cocouter Indicator Draver assembly contains two (2) completely electrically and ucchanically isolated chcnnels with shield barriers between cach channel.
Ecch computer indicator channel is identical and incorporates the following circuits:
1.
Discriminator 2.
Pulse Shaper 3.
Driver 1
Iog Pulse Integrator g
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Level Amplifiers 6.
Bistable Alarm Amplifiers 7
Test Calibrate Circuits.,
Each of these channels is individually fused with cn indicating type fuse holder.
The esse =blies in cach draver ' ontain two (2) c identical circuits for control and readout of the r.onitored channels.
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APPENDIX A CALVERT CLIFFS W
RADIATION MONITORING SYSTFM There are two rotru y cvitches, operation selector and range selector, a ceter, two (2) fu;es on cach half of the panel face, and four (4) indict. tor larps:
(1) Power ON (2) Chennel Test b
(3) Hidh Aln:n Ub
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(4) Lov Alarm C.
Single Channel Drre.ter Each of the Air Particle Detector assc=blics (APD) in the system requires control circuits for the pumps, the filter paper assembly, and solenoids. A single computer indicator channel is counted into a draver and the switches and indicators necessary for control of the Air Particle Detector are counted in place of the second channel.
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Meters Both types of front panel neters have the same nochenical dimensions and bas'ic covecents, but the dial faces.are marked differently.
Area monitor neters are rarhed and calibrated in decades of Roentgens per hour (10 R to 10'R/ hour log scale).
Process ncters nre ucrked and eclibrated in decades of counts per minute (10 to 10 cpm log scale).
E.
Air Particle Detector (A.P.D.)
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The Air Particle Detector, hercarter referred to as A.P.D., nonitors gn=ma activity which night be carried by particulate tatter in the 6
air over a range of 10 to 10 cpm.
A rotary switch for sc=ple
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source selection is located on the front panel of the A.P.D. Draver.
O A floor-=ounted, drip-proof enclosure houses the detector assembly,
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the filter-paper asscnbly, the~ pu: ping system, and related corponents.
- APPENDIX A CALVERT CLIFFS M
RADIATION MONITORING SYSTFM P
The A.P.D. requires 10 SCFM of air through the filter paper which collects approxicately 99% of all particles of 1 nicron or larger.
The thin Vent A.P.D. filter paper r. oves at one inch per' hour past a sodium iodide crystal detector.
The contain:.ent A.P.D. utilizes a fixed filter which is positioned under the detector.
The detector supplies a count rate signal to the computer indicator draver in the 137 Cs remote operated test source is control console. A 10 uCi installed with the detector to provide a means of checking the detector for proper operation. Visual indications provided at the A.P.D. Draver acceably are:
(1) A High Flov Alarn (2) A Lov Flov Alars (3) Filter Not In Motion Alarn
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h (1 ) Pump On 4
(5) High Pressure
-(6) Vent Inlet, Contain Inlet and Purge Inlet F.
Radio-Gas Monitors The Radio-Gas Monitor Detectors are designed to censure Beta-Ger=a activity in a gas snaple over the range of 10* to 10 cpm.
There are two (2) configurations of this detcetor assembly, the Off-Line nodel and the In-Line model.
1.
Of f-Line Model.
Tbc welded steel tank is designed for floor nor ting vith a cyclonic flev around the detectors exis.
The detector used 2
is a beta-Cc:ma sensitive Geiger-l'uller tube with a 30-=s/cm cathode vall operated on a 900+50-volt plateau.
The tube is counted on a cylinder, housing the hi h volttge coupling 6
APPENDIX A CALVERT CLIFFS p
RADIATION MONITORING SYSTDf 7
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circuitry, exactly in the center of the tank volu.:e, parallel 137 to the length of the ' tank.
A 100 uCi cs check nource is counted on the tank to provide a cethod of checking de-tector operation.
A pump is used to supply a sample flow rate if required.
2.
In-Line Model
'Ihe In-Line Radio-Cas Detector is functionally the scne es
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the tenh model, except that the detector is counted in a pipe having 150-lb standard slip-on flanges velded to each end for installation in the appropriate systes.
The detecto'r is counted perpendicular to gas flow being tonitored.
G.
Liquid Monitors Th.e liquid renitore e.re designed to neesure ce.-z.a ectivity in n
( '7 liquid processing line over the range of 10' to 10 cpm.
There are two configurations of the detector assembly, the Off-Line sa=pler and the In-Line Model.
1.
Off-Line Liquid Sample Monitor The Off-Line Scmpler uses a velded noncorrosive senple tant designed for nini=un particle dropout with a continuous senple flow at a maxitum of l$0 psig.
This Staple Monitor Assembly may be supplied for In-Line mounting or floor counting, in the case of small senple lines.
The detector employed is a Sodium 137 Iodine Crystal, that is checked by a 10 uCi cs source mounted to the tank.
2.
In-Line Liquid Monitor
'Ihe In-Line conitor detector essembly is the scne er the Off-Line Model except that it is designed to be directly bolted up to the system p'iping.
APPENDIX A CALVERT CLIFFS we RADIATION MONITORING SYSTE'4 7
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Area Monitors
\\dC.a The Aren Ibnitor is designed to mecsure co-ca radiation in the surrounding environment over the range of 0.1 tr/hr to 10 R/hr.
The detector assc=bly and associated hi h voltcge coupling circuit C
are designed for vall nounting.
Tne detector is a gccr.na sensitive Geiger-! aller tube vith a 90 mg/c=2 cathode vall desi ned for 6
relatively high flux areas.
The vall counting also contains a 90 colenoid actuated 1 pC1 Sr check source to verify detector operability, in addition to a local meter t.nd alarm annunciator.
I.
Plant Main Vent Monitor Assembly Th'e vent monitor assenbly continuously monitors cnd records the airborne radioactive particulate and gasecus concentrations leaving
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the plant main vent.
Badiciodine enneentratinna can he r.cesured in the laboratory by using charcoal collection cartridges which are installed parallel to the A.P.D. sample flov.
'Ihe semple flow is drawn from the rain ' vent through' cn isokinetic no::le by the A.P.D. sample pump at a rate of 20 S.C.F.M.
The cample passes through the airborne particulate detector which discharges to the radio gas monitor and then to atmosphere. The Icokinetic nossic insures that a representative sample is obtained et all times and the particulate detector limits the cas monitor s
to only gaseous radioactive material for monitoring.
The charcoal cartrid es are removed from the parallel semple flow path period-6 ically end analy:cd for specific isotopes of radiciodine to detemine the amount of radiolodine released to the environment via the r.cin vents.
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APPENDIX A CALVERT CLIFFS RADIATION MONITORING SYST24
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Detector Devices j
f There are two detector devices used in the Ecdiation !bnitoring System, the scintillation detector and the Geiger-!suller tubes.
1.
Scintillation Detector The scintillati'on detector is a plug-in unit 'centaining a 1-1/2" by 1" thalliu.n activated codium iodide crystal optically coupled to a photo =ultiplier tube.
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2.
Geiger-!<uller Tubes
. The Geiger-liuller tubes are stcndard beta-gcr=a Geiger-!!uller Radiation Counter tubes operating on a secondary ionization
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2 current principle with a cathode vall of 90 ng/cm for area
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2 detectors cnd 30 mg/cm for ges detectors.
3 Ec=ote Indienter 3
The local indicator dispicys the redirtion level in cpl! for process monitors or Roentgens /hr for area tonitors and also dispicys high alarn signals (red light indication) and an audibic varning (horn indication).
The local indicators are located cdjacent to their radiation detectors.
L.
Check Sources There are check cources locr.ted adjacent to all RIG detectors.
The check source is mounted on a ncchanical lever which positions the check source over a peep hole in the detector chiciding.
The lever is connected to a solenoid which is energised from the operation selector switch located on the channel computer indicator dre.ver.
The quantity nnd isotope used is included on the attached data sheet.
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'Ihe specific response of the R'G chcnnels to' the check source is co'ntcined in 'the' system operatin5 instruction.
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