ML19220B874
| ML19220B874 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 10/28/1977 |
| From: | Herbein J Metropolitan Edison Co |
| To: | Varga S Office of Nuclear Reactor Regulation |
| References | |
| GQL-1483, NUDOCS 7904270559 | |
| Download: ML19220B874 (14) | |
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m t Dceket :10. 50 ^20 license :ic. C? E-66 Attached please find several revised pages to the T:C-2 FSA"..
Tnese pages were finaliced tcc late to be included in FSA.:. ; tend ent 60.
It is cur r.derstanding that ycu need the revised informatien centained en these pages in crder to ec=p ete yor review. We are therefore prcviding this infor:ation at this time.
Inis informatien vill be filed in a future FSAR atendtent.
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The fiaci design of ash rack entcuds outward in -
- ided for=,
in cor.trast to the t e sided model design. Both con arations have perimeters of approximately ft.
The =odel trash rack and surp room s
door were constructed of f.ainless steel grating only, whereas the final design includes a 2 x 2 tesh stainless steel wire screen backing a 1 1/4" x 4" size opening stainless steel grating.
In addition, for conservatis: the final design includes a 4 x 4 tesh stainless steel cover over the recirculation compartment at elevation 289'-6", which is above the maximum calculated water level. Results of the model testing are not affected by these design codification since the model test results indicated that flow perturbations outside the surp room did not influence vortex formation in the roo= and since the changes inside the surp room tend to reduce the influence of the supporting screen structure.
6.2.2.2.1.10 R.B. Su=p Flow Distribution Under normal opera.ing conditions, the flow into the surp origins:es at floor and equipment draits and is received into the surp pump cc partment. The sump purps, taking suction f rom near the surp botto=, dispose of this effluent by pu= ping it out of the building into the liquid radwaste system.
Under accident conditions, reactr coolant spilling onto the reactor building floor will flow into both compartments of the su=p by passing first through the trash racks then the 2 x 2 screen and finally the 4 x 4 screen mesh.
When the decay heat pu=ps and reactor building spray pu=ps are operating in the recirculation code, the contents of the su=p flow into the dual 18" recirculation lines. In this way the reactor coolant and reactor building spray effluent is drawn from the reactor building.
6.2.2.2.1.11 Reactor Building Su=p Debris Elimination Large debris will be restricted fro = entering sump compartments by the 1 1/4" x 4" size opening trash racks with the 2 x 2 #10 wire cesh inter =ediate screen backing provided at each of the openings.
2 x 2 #10 mesh provides a maximum opening size of about 3/8".
Further debris greater than 1/4" in size is eli-
=inated from the decay heat pu=p suction by ueans of the 4 x 4 #16 wire tesh fabric in the vertical screen beside and above the co=partment and also over the overflow opening between the sump pump compart:ent and the recirculation co=-
part=ent.
The 4 x 4 #16 mesh provides a caxi=t2 opening size of about 3/16".
A 1/4" opening size
's adequate to protect both the HPI and LFI pumps and the reactor building spray no::les fron...uge and/or clogging due to particulate matter.
Any debris originating fro = a floor cr equipcent drain will be retained in the sump pump cc part=ent because of the 4'-6" high compart=ent dividing wall.
No floor drains flow directly into the emergency recirculation compartment portion of the su=p.
The opening to the Lerdown Coolers compartment is covered by a door made from structural steel and stainless steel grating backed by stainless steel screening.
The door opens into the Letdown Cooler co=partment. The other opening is pro-tected on the outside by a trash rack projecting out into the reactor building floor constructed fro: structural steel and stainless steel grating backed by 2 x 2 110 resh stainless steel screening.
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AI-73-27 " Hydrogen Reco=biners for Post-LOCA Application" (Proprietary)
AI-73-2'i Rev. 1 (Non-Proprietary)
Al-73-2 " Thermal Recombiner Systers for Uater Cooled Reactors" (Proprietary)
AI-75-2 Rev. 1 (Non-Proprietary)
Electric power for the recc.biner unit is provided by connections with the Emergency Diesel Generator.
The Reactor Building atmosphere is sampled and analyzed to determine hydrogen concentration during and following a LOCA.
When the hydrogen concentration reaches 3.0 percent by volume, the reco=biner syste= will be placed in operation by the operator.
(If the recombiner syste= fails to =aintain the hydrogen level below 3.5 percent by volume, the at=ospheric purge syste= will be placed in cperacion provided suitable atmospheric conditions prevail).
The Reactor Building radiation monitoring system will be used to obtain a sample of the building atmosphere for analysis of its isotopic composition nnd hydrogen content.
This system takes sa=ples free two points in the Peactor Building, which are located approxi=ately 10'10" east and west of the north-south centerline of the Reactor Building do=e.
The samples are transmitted through two lines running from the do=e down and outside to the Reactor Building Air Sample gaseous conitor sche =atically shown as =onitor HP-R-227, "Eadfation lDetectionandSa=pling"onFigure6.2-30.
The sa=pling lines are Seis=ic I.
In the nuclear sa=pling laboratory, the sa=ple will be analyzed with a gas chro=atograph to deter =ine its hydrogen content. A gn==a spectrue analyzer will be used to determine the isotopic co= position of the sa=ple.
Redundant inlet and discharge lines are provided for the ystem to prevent a single active failure of any valve fro i= pairing the function of the =onitoring system.
The at=ospheric purge syste= is shown diagra==atically in Figure 6.2-30.
This systc= is a back up for the hydrogen recombiner system. Up to 150 SCFM of Reactor Building
=osphere is drawn through a filter train consisting of a prefilter, a HEPA filter, a charcoal filter and a second HEPA filter before being discharged to the unit vent by means of a 150 CFM capacity blower.
During at=ospheric purging, the purge exhaust flow is continuously conitored and recorded on Panel 25, so that the exact flow to the environ =ent is known.
To replace the at=osphere exhausted from the building, a 10 in. pressuri-ration valve (AH-V7), located outside the R.B. is provided to admit a
controlled amount of outside air to the building.
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is responsible to the cognizant Proj ec t Engineer for tne technical adequacy of all work in his discipline.
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Project En;ineering B&R has the direct responsibility of designing and engineering TMI-2, preparing procurement and construction design spacifications, and preparing associated drawings for the client. These designs and specifications incorpc: ate and implement all applicable design re-quire =ents and safety criteria for the ite under consideration.
The precurement, design, and construction specifications include specific references to cuces, standards and supplementary testing and acceptance require ents as determined by the end use of the itca under consideration. B&R's engineering cocuments are reviewed by 3&R's quality assurance group to ensure that thesc documents in-corpcrate the necessary quality requirements applicable to the ite:
under consideration.
Engineering has the responsibility for estab-lishing the course of action in regard to deviations frc= the design and construction procurc=ent specifications and associated drawings.
As appropriate, Engineering coordinates and incorporates cc==ents frc=
GPUSC and B&R Quality Assurance Group before finali=ing the recc= men-dations for action in regard to deviations. Engineering coordinates with GPUSC and the B&R Quality Assurance Group before approving con-tract changes.
d.
Project Ouality Assurance The overall B&R Quality Assurance effort is under the direction of the B&R Director of Quality Assurance who reports to the President of Burns and Roe.
The Director of Quality Assurance has sufficient organizational freedom to identify quality assurance problems and initiate the necessary corrective action.
A Quality Assurance Senior Group Supervisor is assigned to TMI-2 by the B&R Director of Quality Assurance. The QA Senior Group Supervisor has the responsibility for all actions affecting quality in the realm of prepurchased equipment and site construction. The Senior Group Super-viscr has organizational freedom in that he reports directly to the Director of Quality Assurance with respect to quality assurance problems.
The QA Senior Group Supervisor is assisted by a Hoce Of fice and Site QA Supervisor.
The ELR Home Office Quality Assurance during the design phase of the project perforns quality assurance reviews on the B&R Engineering-prepared procurement, design and construction specificiations to ensure that such ite=s as the 1311cwing are included: acceptance standards, bAR quality assurance co= itsents, codes and document retention.
bb.N3 17.1-5
222.45/8.2 State the results of an evaluation of the design of your facility's Class IE electrical distribution system to determine if the operability of safety related equipment, including associated actuation control circuitry, can be adversely affected by short term or long ters degradation cf the grid systen voltage within the range where the offsite power is counted on to supply important equipment. Your response should include all of the following:
1.
The voltage used to describe the grid distribution systems is usually a " nomina]" value. State the normal operating range of the grid system voltage and the corresponding voltage values at the 4.16KV Engineered Safety Features Buses and the 480 volt safety-related substation buses.
2.
The transformers utilized in power systems for providing the required voltage at the various system distribution levels are nor= ally provided with taps to allow voltage adjustment.
Provide the results of an analysis of the design to determine if the voltage profiles at the safety related busu' (as defined above) are satisf actory for the full load and minimum load conditions on the system and the range of grid voltage. Describe the tests or other measures that will be taken, prior to plant operation, and after initial power operation, to verify the adequacy of the design in this regard.
3.
Identify the physical location of sensors and provide the trip setpoint for the facility's Loss of Offsite Power (undervoltage irip) instrumentation.
Include the basis for the trip setpoint selection.
4 Assuming degradation of the offsite power grid system voltage, provide the voltage values at the safety related buses corresponding to the max-imum value of grid voltage, and to the degraded grid voltage, corresponding to the under voltage trip setpoint.
5.
Utilizing the safety related bus voltage values identified in (4), evaluate the capability of all safety related loads, including related actuation control citcuitry, to perforn their safety functions.
Include a definition of the voltage range over which the safety related components, and non-safety ec=ponents, can operate continuously in the performance of their design function.
6.
Describe the bus voltage monitoring and abnormal voltage alarms available in the control roo=.
RESPONSE :
When the solid state undervoltage protecticn scheme is installed at the first refueling, the safety related buses will be protected against both the effects of a degraded grid condition and a total loss of power event.
Actuation of these relays will be through a two-out-of-three logic which will shed the loads on these buses and start their respective diesel generators upon sensing a degraded grid voltage condition. A faster actuation will be obtained in the of a complete loss of powcr through a different combinacion of these event relays in a tuo-cut-of-two mode.
S3-222-45
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In the degraded grid voltage mode, tripping of the 4.16KV buses will occur at l
a voltage level which is just above thn equivalent minimun value required to I
91fely operate the magnetic starters, fc the 480V motor control centers, with-out blowing their control fuses.
TF.s minimum value will not ce reached unless the grid vol~tage decays below 209Kt, at indicated on Table 8.3-4.
Based on r.otor control center manufactu ers' data, the minimum calculated bus voltages required to actuate the magnet: c starters are 407V and 403V for General Electric and ITE type cotor cont ol centers, respectively.
Included in these values is a 6T. voltage drop allcwed for control circuits, and 1.5*.
voltage drop for feeders between unit stations and motor control centers. The voltage levels on the 230KV and 4.16KV buses corresponding to these minimum required =otor control center bus voltages are those listed in Table 8.3-4 Using the minimum voltage required at the 4.16KV bus, the corresponding min-imum voltage at the undervoltage relay terminals was established by using the potential transformer transformation ratio. This voltage was cetermined to be 10D.7 volts, and the undervoltage relay nearest setting of 10lv will be used.
At this setting the undervoltage relays will operate in approximately S seconds when the grid voltage decays down to the mini =us voltage required (209KV) to safely operate the magnetic starters in the motor control centers. Also, con-trol circuit fuses have been used in the cotor control centers whose celting tino characteristics are such that, in the worst case, it would take a minimum of 24 seconds before a fuse blowout could occur, if a magnetic starter is called upon to operate at the ti=e that that grid voltage falls below the above mentioned minimu2 required voltage. The Diesel Generator would tnen start an. would accept lead through the Loss of Power sequencer.
Since at this degraded voltage level the undervoltage relays will operate in approximately 8 seconds, and at the same voltage fuse melting will occur in 24 seconds or = ore, the control circuits will be protected against a fuse blowout occurence.
Assuming degradation of the offsite power grid systen voltage, the voltage values the cafety related buses corresponding to the undervoltage trip setpoint and at to the maximum value of grid voltage are given in Table 222.45-1.
The voltage range over which the safety related components and non safety related components can operate continuously in the performance of their design function is described in Section 8.3.1.2.1.
S3-222-45a
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Provisions will be made for the periodic testir.g of these relays during plant operation.
The nc=inal operating voltage of the grid systen is given in Section 8.3.1.2.2.
The voltaga profile at the various saf ety related buses is shown on Table 5.3-3.
Table S.3-4 shows the voltage range for safe equipment operation. A description of transformer tap settings is provided in Section 8.3.1.1.1.
Tc'. ting to verify system adequacy in providing voltage to safety related buses as required for full load and mini =um load conditions and the range of grid voltage vill be perforced as described in the response to Question 222.46, Fositien 4 The 4.16EV buses are provided with voltmeters located both in the main control room and locally counted at the switchgear. Undervoltage alar in the Control Rocn is attuated simultaneously with the tripping of the buses. The 480V buses are provided with voltceters locally counted.
In addition, bus voltage indicat-ing lights in the Control Room have been provided.
S3-222-45b
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Table 222.45-1 VOLTAGE VALUES AT SAFETY RELATED l
EUSES-ASSUMING OPERATION ON OFFSITE POI.T.R l
A'!D DEGRADATION OF GRID SYSTEM VOLTAGE (FULL LOAD)
(1)
(2)
Eus Minimum Voltare 5bximum Valr.aee i
230KV GRID 209KV 241.5KV 4.16KV 2-lE 3.526KV 4.162KV 4.16KV 2-2E 3.535KV 4.171EV 4.16KV 2-3E 3.526KV 4.162KV 4.16KV 2-4E 3.526KV 4.162KV 480V 2-llE 407V 479V 480V 2-21E 407V 482V 480V 2-12E 412V 489V 450V 2-22E 415V 490V 420s 2 117 415V 4S7V 4807 2-415 414V 487V 120V 2-11EB 100V 11SV (1) Voltage values correspond to under voltage trip setpoint.
(2) Vol: age values corrcspond to maximum expected value of grid voltage.
S3-222-45c N?} "Q
i che grid syster tc which Three Mile Island Uni
- 50. 2 is connected has a nominal operating voltage of 230KV. The normal operating range of f
th e gria is 232KV to 23SKV. The calculated expected voltage values the 4.16KV Engineered Safety Features buses and the 480V and 1207 l
at s<.fety related substation buses corresponding to the normal operating range of the grid system voltage at Full Load and So Lead Conditions are sho;cn in Table 6.3-3.
provided with 2 undervoltage relays.
Individual testing of these rel-s can be accomplished by actuating a comentary push butten located in the contrcl roon, which disconnects bus voltage input to the relay. An amber light at the push button comes on indicating relay circuit integrity.
In addition, a white light con-tinuously ponitors the integrity of the associated auxiliary relay.
The 4.16K7 buses are provided with voltmeters located both in the main control room and locally =cunted at the suitchgear. Undervoltage alarm in the Control Room is actuated simultaneously with the tripping of the busea.
The 480V buses are provided with voltmeters locally counted. In addition, bus voltage indicating lights in the Control Room have been provided.
The voltage limits within which the safety related and non-safety re-lated components can operate continuously in the perfor=ance of their design functions based on equipment canufacturers' data are listed in Table 8.3-4 Based on Pennsylvania-New Jersey-Maryland Interconnection criteria, the taxi =um operating limit of the 230KV grid voltage is 241.5KV (105% en a 230KV base) and the minicus operating limit is 218.5KV (95% on a 230%V base). The equipment safe operating range falls well within the operating limits. In addition, by the end of the first refueling cycle solid state undervoltage relay system for the 4.16KV safety related e
bases will be incorporated into the plant which will provide two levels of undervoltage protection. A more detailed description of this system can be fcund in the response to NRC Question 222.45, Supplement 3.
8.3-10a F7 n3
TAELE 8.3-3 CI)
VOLTAGES PROFILES AT TiiE SAFETY RELATED EUSES No Load (2)
Full Load Bus Min. Normal Max. Normal Min.Nor al Max. Nor.al 230KV GRID 232ix 238KV 232KV 238 4.16KV 2-1E 4.296KV 4.407KV 3.9811T 4.106 4.16KV 2-2E 4.293KV 4.406KV 3.991FV 4.111 4.16KV 2-3E 4.2961N 4.407KV 3.981K1 4.106 4.16KV 2-4E 4.296KV 4.407KV 3.9E1KV 4.106 480V 2-11E 50SV 521V 458 473 480V 2-21E 50SV 521V 461V 475 480V 2-12E 508V 521V 468V 473 430V 2-22E 503V 521V 469V 475 480V 2-31E 507V 520V 466V 480 430V 2-41E 507V 520V 466V 480 120V 2-11EB 121V 130V 113V 116 (1) Based on tap settings of 2.5% below 2301N and 4.16KV for auxiliary trans-formers (230/6.9/4.16KV) and USS transformers (4.16/.48KV) respectirely.
(2) No Load Condition is assumed when the unit is shutdown and only the essential services are fed from the corresponding buses.
TABLE 8.3-4 VOLTAGE RANCE FOR SAFE EQUIPMENT OPERATION Safe Operating Range Device Desien Value Minimum Voltage Maximum Voltage Motors 4000V 4000V 3600V 4400V Motors 460V 460V 414V 506V
>bgnetic Starters 480V 384V 52SV Solenoid Valves 120V 102V 140V Instruments 120V 102V 140V S.3-29
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GDI 17 requires that provisions be ' ml;ded to tir'-ize the probability of losing electric p~
from any on>
the re-taining supplies as a result of er e., incident with t e loss ci pcwcr generated by the nucica-power unit, t!.e lo of power from the transmission ae work, o; the loss of power 'rora the onsite electric power supplies.
The testing requirements identified in Position 3 will demon-strate the capability of the onsite power system to perfor:
its required fune:1on.
The tests will also identify undesirable interaction between ene offsite ar.d onsite e=ercency power systems.
- 4) Position 4: Ooti=1:ation of Transformers Tap Settines The voltage levels at the safety-related buses should be opti-cized for the full load and minimum load conditicas that are expected throughout the anticipated range of voltage variations of the off site power source by appropriate adjust =ent of the vcitage tap settings of the intervening transformers. We re-quire that the adequacy of the design in this regard be verified by actual reasurement, and by correlation of =casured values with analysis results. Provida a description of the method for making this verification; before initial reactor power operation, provide the documentation required to establish that this verification has been acco=plished.
RESPO';SE:
Position 1 Protection against the adverse effects of a degreded grid condition will be implemented by a two cut of three logia solid state relay systen shich will be installed prior to the enc of the first refueling outage. This system will comply fully with the above criteria. A de-scription of the necessary design modifications has been included in the response to NRC Question 222.45.
S3-222-46d C
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4ESPOSSE (CONT.)
Pacition 2 The load shedding f eature is described in Section 8. 3.1.1.S. 5.
This fccture is autcastically and permanently bypassed once the onsite sources start supplying power to the sequenced loadc on the emergency buses. This is accc plished through auxiliary contacts from the on-site power s.tpply breakers which energize their respective load se-quencer which in turn will discontinue the bypassing signal to the laod shedding feature.
Thus, the load shedding feature will bc auto-matically restored if the onsite power supply breakers are tr pped.
d Therefore, TMI-2 ce= plies cocpletely with this position.
Position 2 TMI-2 Technical Specifications will be revised to include the testing requirements of this position.
Posi_ tion 4 Voltage tap settings for the auxiliary transformers and USS transformers are described ir FSAR Section 8.3.1.1.1.
Adequacy of the design in regard to optimization of voltage levels at safety related buses will be proved by the i=plementation of a program of electrical reasurements on the various buses throughout the plant.
Readings will be taken on all the 6.9KV, 4.16KV and 480V ouses. For the high voltage buses, the readings will consist of measurements of voltage, amperes and watts.
For the 480V buses, both voltage and amperes will be tonitored. This data will be converted to equivalent loads on the various buses and these loads will be fed to our voltage drop calculation program. The bus voltage results from the program will be co= pared uith the actual voltage readirgs. These measure =ents will be taken in the early part of January 1978 when sufficient loads will be running on the various buses to provide meaningful results.
Documentation that this verification has been acco=plished will be provided prior to initial power operation.
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222.a7 With regard to all Clcss lE equipment located outside the containment building we require documentation which states that all of this equipment has been certified to satisfy the applicable industry standards (e.g. NEMA and ANSI).
Further, we require assurance that the environcent at the equipment location is maintained within the temperature range for which the equipment is quali-ficd to operate.
In those locations where the temperature could exceed that for which the Class 1E equipment is qualified, the stafi requires that the applicant provide a temperature monitoring system. The system should, at a minimum, meet the following requirements:
- 1) T? 2 centrol room should receive an alarm when the te=perature range has been exceeded. This alarm should be provided by in-strumentation which:
(a) is of high quality, (b) is checked to verify its functional capability by plant technical specification requirements, and (c) is powered froa a continuous power source or is redundant with separate channels and power sources.
- 2) The operator should have a method of =aintaining a continuous record of the te=perature during the time that the temperature range is exceeded.
Based on the monitoring system, the applicant shall report the occurrence of the temperature exceeding the equipment qualification range and its duration as a license event report to the NRC.
In addition to this, the applicant shall provide results of an analysis to demonstrate that the excess temperature has not degraded the involved Class lE equipmant below an acceptable level for continued plant operation.
RESP 0NSE:
Design specifications for all Class lE equipment located outside containment include require:ents that equipment satisfy applicable industry standards.
Documentation is available to attest that all equipment meets the specifica-tions and therefore all equipment meets applicable industry standards.
The following is a description af the equipment which will be installed prior to the end of the first refueling outage, to comply with the above requirements:
Fast response platinum RTD te=perature sensors will be provided in all areas outside the containrent in which Class lE equipse.: is located. A solid state data logger will be provided as a temperature monitor alarm and recording sys-tem for the conitcring of these a bient temperatures.
Gq m9 S3-222-47
This monitoring systen will be a E0? system fed frem the Class lE vital power supply. The conitoring syster vill comply ecepletely uith the above criteria. The data logger system vill consist of two units. One unit is a satellite unit in the cable roer uhich collects all the RTD s i:;nals, converts them to digital outputs, and sends then to a dispicy unit in the control roo=.
The display unii in the control room can be programmed to continuously tonitor all points or it can be set to scan all points at presclected intervals.
In the event the preset 11=it is er.ceeded in any one of the points, both audible and visual alarms will be generated by the display unit.
Printout of all the points, or just the off-limit points, Jill be available in the control room both on continuous and autocatic code, or manually at operator request. Time-of-day will be automatically recorded for both the start and the end of the alarm condition.
In addition, the system will conitor continuously the circuit integrity cf all scasors and will also alar = in the event of any sensor circuit discontinuity such as a broken wire.
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