ML20244D814
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APR 2 3 I3N MEMORANDUM FOR: Victor Nerses, Project Manager, Pro.iect Directorate 45 Division of PWR Licensing-A FROM: C. E. Rossi, Assistant Director for Technical Support Division of PWR Licensing-A SU8k1ECT: SUPPLEMENTAL SAFETY EVALUATION REPORT - SEABROOK UNIT 1&2 Plant Name: Seabrook Units 1 & 2 Utility: Public Service of New Hampshire Docket Nos.- 50-4a3/444 Licensing Stage: OL /
Project Manager: Victor Nerses Responsible Directorate: PD #5/PWR-A Review Branch: EICSB/DPA Review Status: Complete The enclosed supplement to the Safety Evaluation Report was prepared by the Electrical, Instrumentation and Control Systems Branch / Division of PWR Licen-sing-A for inclusion in Seabrook SSER No. 4 This SSER covers 11 the resolu-tion of concerns identified during our site visit conducted on September 24 thru 26,1985 by 0. Chopra and Peter Kang, 2) discussion of certain items identified in the SER to be verified during our site visit and 3) the results of our evaluation of additional information suomitted by the applicant on the confirmatory issues identified in the SER oublished in March,1983.
As discussed in Enclosure 1, we conclude that all items with the exception of items 10 and 11 of Section 8.3.1.8 of the SSER have been acceptably resolved.
We shall report the resolution of the above items in a supplement to this re-port. The SALP for this evaluation is provided in Enclosure 2.
C. E. Rossi, Assistant Director for Technical Support Division of PWR Licensing-A
Enclosures:
Distribution: 1 As stated -Document Control 016 EICSB Rdg.
cc: V. Noonan O. Chopra (PF)(2)
S. Weiss
Contact:
F. Rosa j
- 0. Chopra, EICSB/DPA C. E. Rossi 1 I
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SUPPLEMENTAL SAFETY EVALUATION REPORT SEABROOK STATION 8.0 ELECTRICAL POWER SYSTEMS 8.1 General We stated in the Safety Evaluation Report that the staff would conduct a review i of electrical drawings and would visit the site to view the installation and ar-rangement of electrical equipment and cables for the purpose of verifying proper implementation of the design as described in the FSAR. In addition, we identi-fied certain items in the SER for design verification during our site visit. A site visit was conducted by the staff on Septembe" 24 thru 26,1985 daring which certain concerns were identified. Our discussion and resolution of these con-cerns are addressed below. Items for design verification and confirmatory issues identified in the SER are discussed in the appropriate sections of the SSER.
(1) During the site visit, the staff review of the DG control drawings revealed that if the DG control switch is in the local position, the DG will be unavailable for auto start on a SI sianal. This condition was not alamed in the control room as part of the con-ditions that can render the DG incapable of responding to an auto-matic emergency start signal. The staff required that this condi-tion be included in the list nf conditions that can render DG in-capable of responding to an automatic emergency start signal to satisfy BTP PSB #2.
By letter dated November 27, 1985, the applicant committed to in-clude this condition in the list of conditions that can render the I
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DG incapable of responding to an automatic emergency start signal.
This satisfies BTP PSB #2 and is acceptable. Verification of the .
implementation of this design will be performed by Region I.
1 (2) The staff's review of the control circuitry of recirculation isola- )
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tion valve (SI-Y-93) revealed that redundant indication that meets the single failure criterion was not provided for this valve (redundant indicatien had been provided but from the same valvelimitswitch). The staff required that another indication from a diverse device (e.g., stem mounted switch) be provided to '
satisfy BTP #18. .
By letter dated November 27, 1985, the applicant committed to in-stall another indication from a stem-mounted switch. This satisfies BTP #18 and is acceptable. Verification of the implementation of this design will be performed by Region I. j (3) The staff's review of the circuits for penetration protection re-vealed that the breaker control power supply for primary and back-up protection for structure cooling fans does not meet the single failure criterion, i.e., it is not from different batteries. The 1
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staff required that the breaker control power for primary and back-up protection for these fans be from different batteries to satisfy k l
the recommendations of R.G. 1.63, Position 1.
i By letter dated November 27, 1985, the applicant indicated that the breakers for the above cooling fans do not require control power to trip in order to isolate a fault'. These breakers utilize a direct acting electro-mechanical overcurrent trip device which !
depends on its circuit for tripping power. Hence, no external control power is required for tripping. Based on the above, the staff considers this concern resolved.
- 8. 2. 2. 3 Routing of Offsite Power Circuits In the Seabrook design, the three offsite power circuits are routed, from the terminating structure to a common switching station, in close proximity at or below ground level and adjacent to the plant's access road. These circuits are
., routed in a metal-enclosed SF6 gas insulated bus. The plant's main access road j runs adjacent to and has a number of bridges across the transmission line routing. One of the bridges is an access road to a public recreation area. 1 1
The staff was concerned that a vehicular accident could damaoe all three off- !
site circuits simultaneously. In response to staff's concern, the applicant l
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indicated that protection of the transmission lines fror, vehicle damage 1s pro- )
1 vided by guardrails, the location of the access road on plant property, con-trolled access, and strict plant regulated speed limits. The staff stated in i the Seabrook Safety Evaluation Report that the design of offsite power is ac-ceptable pending confirmation of guardrail design adequacy and/or the low like-lihood of vehicular type accidents.
By letter dated November 27, 1985, the applicant submitted the guardrail design for staff review. The adequacy of the design of guardrails for protection of the offsite power circuits from vehicular accidents was reviewed and evaluated by the Engineering Branch / Division of PWR Licensing-A. Based on their evalua-tion, the staff concludes that the applicant has minimized the likelihood of simultaneous damage to the three offsite circuits. Therefore, the design reets GDC 17 and is acceptable.
8.2.3.1 Capability to Test Transfer of Power Among the Offsite Circuits J The capability to test the transfer of power from the imediate access offsite circuit to the other circuit was not addressed in the FSAR. We stated in the SER that pending incorporation of the applicant's response in FSAR Section 8.2, the staff concludes that the design meets GDC-18 and is acceptable. Subse-quently, the applicant amended FSAR Section 8.2 to include this information. .
l This satisfies the staff's concern and the staff considers this item resolved. '
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, 8.3.1.1.1 Compliance with Position B1 of BTP PSB-1 The second level of undervoltage protection for the Seabrook design does not meet the guidelines of position 1 of BTP PSB-1. The design relies strictly on l l operator action when there is no accident signal for disconnection, rathcr than on automatic disconnection after a time delay for the operator to restore ade-quate voltage. In addition, immediate rather than delayed automatic disconnec-tion was to be initiated if there were a coincident accident signal.
. 1 In regard to the first exception, the applicant indicated that adequate safety systems (not exposed to or not rendered inoperable by degraded grid voltage) I d
are available for safe shutdown. The staff stated in the Safety Evaluation Re-port that this approach is acceptable for the resolution of this item, however, the adequacy of systems and equipment used for safe shutdown and exposed to de-graded grid voltage will be pursued with the applicant.
Subsequently, by letter dated November 27, 1985, the applicant submitted a list i of systems and equipment not expnsed to or not rendered inoperable by degraded voltage. The staff has reviewed this information and concludes that sufficient i systems and equipment required for safe shutdown will be available in the event of a degraded grid voltage. Most of these systems are either not operating dur-ing normal plant operation or do not rely on electric power for operation. For safety equipment which is running normally, redundant equipment exists in stand-by unaffected by degraded grid condition. In some cases eouipment relies on DC l
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power for operation and all instrumentation is connected to 120 VAC uninter-ruptable power supply (inverters backed up by batteries) which is unaffected by degraded grid voltage conditions. Based on the above, the staff considers this item resolved.
In regard to the remaining exception to the BTP PSB-1 position (immediate rather than delayed automatic disconnection when there is an accident signal), the applicant indicated that the Seabrook design has the required delayed automatic disconnection. The staff has confirmed the implementation of this design feature in the Seabrook design and considers this item resolved.
8.3.1.1.3 Compliance with Position B3 of BTP PSB-1 (1) The staff stated in the Safety Evaluation Repor, that: Table 2 of the voltage analysis indicates that starting the non-safety motor CAH-FN-1C will cause a voltage drop on the associated non-class 1E bus, below 80%. The staff concluded that pending confirma-
.. tion that this voltage drop is localized and will not cause a similar drop on class IE buses, this iten is acceptable.
By letter of November 27, 1985, the applicant submitted a revised i
voltage analysis. Based on staff's review of Table 2 of the voltage I
analysis, the staff concludes that starting the non-class IE motor ]
CAH-FN-1C has no adverse effects on the class IE buses, i.e., the
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voltage on the class IE buses remains above 80t. This satisfies j staff's concern and the staff considers this confirmatory item resolved.
(2) The staff' stated in the SER that Table 3 of the voltage analysis con-siders starting of all accident loads simultaneously. The table con-siders other cl. ass IE loads that are running when the accident loads '
are started but does nnt address non-class IE loads that are running or that may start during the same t une interval that the class IE loads are starting. The staff concluded that pending confirmation that startino and running of non-class IE loads has been considered in the study, this iten is acceptable.
By letter dated February 24, 1986, the applicant submitted revised Table 3 of the voltage regulation study, which included the effect of starting non-class 1E loads coincident with accident loads on the E. class 1E bus voltages. The staff has reviewed this table and con-I cludes that all voltages at the motor terminals are above the 80%
voltage required for starting class IE motors with the exception of !
voltages at the terminals of fans EAH-FN-4A (79%) and 4B (77%).
However, these fans are capable of starting with terminal voltages of as low as 75% because these motors are only 72% loaded (based on i applicants discussions with the fan vendor). Based on the above, the staff finds this item acceptable.
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8-(3) The staff stated in the SER that Table 4 of the analysis indicates a 2.9% overvoltage at the safety buses during the condition of ;
l minimum anticipated loads with the utility grid at maximum antici-pated voltage. Pending confirmation that there will be no over- j voltage at.the motor terminals, the staff finds this item acceptable.
By letter dated November 21, 1985, the applicant submitted a revised voltage study. This study indicates the maximum overvoltage condi-tion to be 0.8% rather than 2.9% in the original submittal. The applicant has stated that a nominal motor feeder voltage drop of 1% should ensure that no overvoltage condition exists at the motor 1
terminals. This meets Position 3 of BTP PSB #1 and the staff finds it to be acceptable.
(4) The voltages at the 120/240V distribution panel buses will vary be-tween 109.9 volts and 128.9 volts. For short periods, during voltage y dips due to motor starting, the bus voltage may drop to 95.8 volts. i A transient undervoltage condition of 95.8 volts and a steady state of 129 volts would have no adverse effect on the instruments for the level indication. The staff stated in the SER that pending confirma-tion that the level indicators are designed to operate between 110 to.
129 volts, the staff finds this item acceptable.
By letter dated November 27, 1985, the applicant indicated that this particular level indicator is no longer supplied power via the non-regulated class IE 120V ac power distribution panels. A review l
was performed by the applicant to identify any other typical class {
1E instrufnents which are supplied power from the non-regulated class IE 120 VAC system. As a result, another model level indicator was 4 l
identified with a nominal operating voltage range of 115 8% (105.8 ;
to124.2V). The applicant has submitted confirmation from the manu-facturer that a supply voltage of 105 to 130V ac is acceptable for this instrument. Based on the above confirmation, the staff con-siders this item resolved, l
8.3.1.1.4 Compliance with Position B4 of BTP PSB-1 This position requires that the analytical techniques and assumptions used in the voltage analysis performed to optimize the class 1E bus voltages for Posi-tion 3 of BTP PSB #1, must be verified by actual measurements.
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By letter dated January 23, 1986, the applicant submitted the results of a test which was conducted to verify the analytical results of the Seabrook Station .
Yoltage Regulation study. The staff has reviewed the results of this test and concludes that Seabrook onsite power system meets BTP PSB #1 and is acceptable.
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8.3.1.2.1 Frequency Recovery (BTP PSB-1 Position C5)
An earlier revision of FSAR Section 8.1.5.3 indicated an exception to Position C-5 of Regulatory Guide 1.9. This position recomends that during loading se-ouence, frequency should be restored to 60 1.2 Hz within 60% of the load se- I quence interval. The R.G., however, permits a greater percentage of the load sequence interval for recovery if it can be justified by analysis.
By letter dated March 12, 1982, the applicant indicated that the Seabrook design meets Position C5 and that Section 8.1.5.3 would be modified accordingly. The staff stated in Seabrook SER that this item is acceptable pending confirmation that the FSAR has been modified accordingly. Subsequently, the applicant modi-fied the FSAR Section 8.1.5.3 to remove the exception. The staff has reviewed
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the revised FSAR Section 8.1.5.3 and concludes that the Seabrook design conforms to BTP PSB-1 Position C5 and considers this item resolved. f l
- 8. 3.1. 2. 3 Diesel Generator Qualification Tests
. The staff requires that new and previously untried diesel generator designs to be used in nuclear plants ur. ergo a prototype reliability qualification testing 4
program in accordance with IEEE Std. 387. Specifically, a 300 start-and-load test program is required with no more than three failures. The staff stated in i
the SER that this item is acceptable pending review and confinnation of the pro-gram test report.
By letter dated November 27, 1985 the applicant submitted for staff review the results of the diesel generator qualification testing program. Based on this i information, it is concluded that the diesel generators at Seabrook plant have successfully passed a prototype reliability verification program of 300 valid j l
start-and-load tests .with no more than three failures. Therefore, the staff considers this item resolved. I l
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- 8. 3.1. 2.4 ' Diesel Generator Automatic Controls Section 5.6.2.2(1) of IEEE Std. 387-1977 (endorsed by R.G.1.9, Rev.1) requires i
that a start-diesel signal shall override all other operating modes and return i b
control of the diesel generator unit to the automatic control system. Based on the FSAR, it appeared that control of the diesel generator was not returned to the automatic control system as required by the standard.
By letter dated July 2,1982, the applicant provided a proposed change to the ,
l l FSAR. Based on this proposed change, the staff concluded in Seabrook SER that j
, the diesel generator control will be returned to the automatic control system and is acceptable pending verification of the design as part of staff site visit.
Subsequently, a site visit and an audit drawing review was conducted on Septem-ber 24 through 26, 1985. During the site visit, the staff examined schematics 1
showing the design for returning control of the diesel generator unit to the l automatic control. system on receipt of a SI signal. Based on this verification the staff considers this item resolved.
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8.3.1.2.5 Diesel Generator Voltage Capability The Class 1E motors for Seabrook design are capable of starting and acceler-ating their rated load with 80% voltage at the motor terminals. The output voltage of the diesel generator can, however, drop to 75% as permitted by Position 4 of R.G.1.9 (Rev. 2). The applicant indicated that Seabrook diesel generators are designed to limit the output voltage to a minimum of 80% and that this capability has been demonstrated by factory load tests.
The staff stated in the Seabrook SER that the capability of the diesel gener-ator to maintain voltage levels above 80% will be verified as part of our re-1 view of diesel generator qualification test results.
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By letter of November 27, 1985, the applicant submitted the results of the diesel generator qualification testing program. Based on staff's review of this information, it is concluded that the Seabrook diesel generators are capab',e of r.aintaining voltage levels above 80% during sequencing of loads on the safety
'. buses. Therefore, the staff considers this item resolved.
8.3.1.2.6 Capability of the Diesel Generator to Acceot Design Load The cooling tower pump load (800 hp) that is nomally connected at time interval )
37 seconds may be connected at the 52 seconds time interval or any time after 52 seconds. The staff was concerned that the diesel generator may not be able to pick such a heavy load at or after 52 second interval. The applicant indi- l cated that the diesel generator has been tested to demonstrate its ability to
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I successfully start a load larger than the 800-hp cooling tower pump at the 52-second loading sequence interval.
The staff stated in the SER that pending review and confirmation of the subject test this item is considered acceptable.
By letter dated November 27, 1985, the applicant submitted the results of diesel generator qualification testing program. Based on the results of this program, 1
the staff concludes that the Seabrook diesel generator is capable of starting a 1000-hp moter after being loaded to 4560KW. This is more conservative than starting a 800-hp motor at the 52-second time interval (3885 KW) and the staff l finds this to be acceptable. However, periodic testing using the 800-hp load at 52 seconds will be included in the Technical Specifications.
8.3.1.2.7 Diesel Generator Protective Trips The staff stated in the SER that the Seabrook diesel generator protective trips meet the guidelines of Position 7 of RG 1.9 and are acceptable pending design confirmation by the staff during its site visit and drawing review.
Subsequently, a site visit and an audit drawing review was conducted on Septem-ber 24 thru 26,1985. During the site visit, the staff examined diesel gener-ator control schematics showing bypassing of protective trips (all except over- !
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speed, generator differential and lube oil pressure with a two-out-of-three coincidence logic) during accident condition. Based on the above verification of the design, the staff considers this item resolved.
8.3.1.2.8 Capability of Diesel Generator to Accept Design Load After Operation at Light or No Load Originally, the applicant indicated that electric pre-heaters are necessary for no-load operation of the diesel generator without the accumulation of products of combustion in the exhaust system when the turbocharger inlet air tempera-ture is below 50*F. The applicant stated that the preheaters will be (1) auto-rnatically energized when there is a safety injection accident signal, offsite power is available, and there are low ambient conditions; (2) automatically de-energized or tripped when offsite power is or becomes unavailable; (3) powered from the diesel's associated class IE bus; and (4) seismically supported. In addition, the circuitry associated with the preheaters will meet class 1E de-I sign requirements. The staff stated in the Seabrook SER that pending confirma-
, tion of the design implementation, the staff considers this item to be resolved.
By letter dated November 27, 1985, the applicant indicated that based on their discussion with the diesel manufacturer, they have determined that preheaters in the diesel air intake plenum are no longer required. Based on the accept-ability of not having the preheaters in the diesel air intake plenum when the turbocharger inlet air temperature is below 50*F as evaluated in Section l
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l 9.5.4.1 of this report, the staff concludes that the implementation of the pre-heater design discussed above is no longer required and the staff finds this item resolved.
l The staff also stated in the SER that as part of the review of the diesel gen-erator qualification and preoperational test results, the capability of the diesel generator to accept design load after operation at light load or no load will be verified by the staff, i By letter dated November 27, 1985, the applicant submitted the results of the diesel generator qualification testing program. Based on the results of this I testing program, the staff concluded that the Seabrook diesel generators are l
l capable of accepting design load after operation at no load for six hours.
This satisfies the staff's concern and is acceptable. The acceptability of the test results from the preoperational testing program will be performed by Region I. Periodic testing to demonstrate this capability will be requirc3
. by the Technical Specifications.
8.3.1.4 Nonsafety Load Powered from the Class 1E AC Distribution System The non-Class 1E 1500-hp startup feed pump is normally connected to non-safety related bus 4 with an alternate (manually initiated) feed from safety-related bus E5 only under contingency conditions. The capability of the Class IE system to handle this 1500-hp load, when it is already carrying the maximum train A loads, concerned the staff. In response to this concern, the applicant stated l
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1 that the diesel generator is capable of starting and powering the startup feed pump when carrying the maximum train A load listed in FSAR Table 8.3-1. In addition, the appMcant stated that operating procedures will include provisions to require that the operator verify diesel generator loading to ensure that adequate mar-gin is available for running the startup feed pump.
l The staff stated in the Seabrook SER that the applicant is required to demon-strate this capability as part of diesel generator load qualification testing program and reoperation and periodic tests. Pending confirmation of load qualification test results, the staff considered this item resolved. Periodic testing to demonstrate this capability will be required in the Technical Speci-fications.
By letter dated November 27, 1985, the applicant submitted the results of the diesel generator qualification testing program for staff review. Based on our I
review of this information, the staff concludes that the diesel generators at
. Seabrook have the capability to handle 1500-hp load without exceeding the guide-lines of Position 4 of R.G.1.9 with regard to voltage and frequency. There-fore, the staff considers this item resolved. Confirmation that the diesel gen-erator can start and run the startup feed pump while carrying the maximum Train A load will remain pending until the preoperational tests are conducted and test I
results are made available. Verification of the adequacy of these test results will be performed by Region I. Periodic testing to demonstrate this capability will be required in the Technical Specifications.
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- 8. 3.1. 8 Automatic Transfer of Loads and Electrical Interconnection Between Redundant Divisions Originally, the power sources to non-Class IE inverters (UPS-ED-I-28, UPS-EO-I-4) were automatically transferred between 4160-V bus ES (safety train A) and l 4160-V bus E6 (safety Train B).
The staff informed the applicant that this i automatic transfer did not meet position 4C of RG 1.6. In addition, this auto-matic transfer or interconnection between redundant divisions did not meet the independence requirement of GDC 17. Subsequently, by letter dated January 7, 1983, the applicant indicated that the power supplies to UPS-ED-I-2B and UPS-ED-I-4 would be modified to eliminate the subiect interconnection and there are no other electrical interconnections or automatic load transfers. The staff stated l in the Seabrook SER that pending confinnation of the modified designs, the staff concludes that the design meets RG 1.6 and is acceptable.
By letter dated November 27, 1985, the applicant submitted the modified design.
Based on review of the modified design, the staff concludes that the power sources to inverters UPS-ED-I-2B and 4 are all derived from train A and there is no connection to train B. Therefore, the modified design meets position 4C l RG 1.6 and the staff considers this item resolved.
l l l l The staff also stated in the SER that physical independence between redundant ac I
and de divisions and between redundant associated divisions is being investi-gated by the applicant and upon completion of this investigation, the results i
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would be submitted for staff review. Subsequently, by letters dated December 1, 1983, June 20, 1984 and November 27, 1985, the applicant submitted the results i of a study performed to identify and justify all electrical interconnections between redundant ac and dc divisions and between redundant associated divi-sions. The staff's' evaluation is as follows: '
- 1. 13.8 KV switchgear feeder breaker compartments for reactor coolant pumps The 13.8 KV switchgear compartments (designated as train A associ-ated) contain train B associated cables. The train B associated cables that enter these compartments are the power feeders for the '
13.8 KV reactor coolant pump motors and the cables for the power connections to the potential transformers (see item 2) which is utilized for the solid-state protection system circuits. A postu-lated failure in one of the switchgear compartments could impact the contained separation group A circuits and specific separation group B cables (feeder to RC pump motors and feeder to the pts).
The cables used for the connections to the PT's are routed in em-bedded conduits and do not intermix with any other separation group circuits.
The cables providing power to RCP motors are annored cables and are routed either in embedded conduits or in dedicated cable trays 1
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containing only those cables. These trays are located at the top of a stack of other Train B trays. The nominal distance be-tween the trays in a stack within a separation group is 16 inches.
Based on the above, the staff concludes that there is only a very remote chince that these armored cables which are routed in dedi-cated cable trays could challenge other associated separation group B circuit,s because 1) cable trays contain only RCP motor j cables, 2) there is a separation of 16 inches between the other trays in a stack, 3) trays are located at the top of the stack minimizing fire propagation to the bottom trays and, 4) the con-nections of associated separation group B circuits to the associ-ated separation group A circuits are thru 13.8 KV feed breakers.
Therefore, the staff finds this interface to be acceptable.
- 2. Compartment for 13.8 KV reactor coolant pump potential transformers These compartments contain the 13.8 KV-120V potential transformers (PT) and associated relaying utilized to provide underfrequency and undervoltage infomation to the SSPS for the reactor coolant pumps, as such, these four compartments are associated with four instrument channels I, II, III, and IV.
The cables connecting the PT's to their power source, the 13.8 KV buses, are train B associated. Therefore, there is a interface be-tween train B associated cables and channels of different separation I
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groups. The 13.8 KV train B associated cables enter the bottom of these compartments and they teminate on a bus. This section of the compartment is isolated by metal barriers '*om the rest of the PT compartment. The bus is routed to another section which con-tains the 13.8 KV-120V PT and class IE fuses. *his section is also isolated from the instrument and relaying secti:n by metal barriers.
Based on the barriers and the class IE fuses wHch provide isolation between the redundant associated divisions, the staff finds this interface acceptable, j
- 3. 4160 volt switchgear compartments for preferred power supplies !
There is an interface between non-class IE preferred power supply (train A associated) and class IE train B switergear. However, this connection from the preferred power supply (UAT or RAT) which is Train A associated to Train B 4160 volt switchgear Bus E6, is done utilizing metal enclosed, non-segregated tF*ee-phase bus duct.
These bus duct runs are independent and do not associate with any other raceway system along their entire length such that a failure on these bus ducts will not affect any other raceway system. Based on the above, the staff concludes that this interface is acceptable.
- 4. Vital Instrumentation Distribution Panels The separation group C distribution panel EDE-PP-10 contains separa-tion group A (Train A and Train A associated) cables and separation
i group C (Channel III) cables. Similarly, the separation group D 1
distribution panel EDE-PP-10 contains separation group B (Train B and Train B associated) and separation group D (Channel IV) cables.
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However, metal barriers are provided within panel EDE-PP-IC to separate Channel III from Train A and Train A associated circuits.
Similarly, within panel EDE-PP-ID metal barriers are provided to separate Channel IV circuits from Train B and Train B associate circuits. Based on the above, the staff finds these interfaces to be acceptable.
Uninterruotable Power Supply The separation group A inverter EDE-1-IC contains separation group A (Train A and Train A associated) cables and a separation group C (Channel III) cable. This cable is a DC power feed to the inverter from battery IC which is designated as Channel III. Similarly, the separation group B inverter EDE-1-ID contains separation group B
. (Train B and Train B associated) cables and a separation group D (Channel IV) cable. This cable is a DC power feed to the inverter from battery ID designated as Channel IV. This interface between the above separation groups exists for all two train and four battery system designs. As a result, there is an interface, by design, between Train A and Channel I, Train A and Channel III, Train B i
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and Channel II and Train B and Channel IV. Based on the above, the staff finds these interfaces to be acceptable.
- 5. Process Protection Cabinets Problems were identified internal to these cabinets where non-vital instrument signals from different separation groups (Train A associ-ated and Train B associated) were routed together without proper isolation devices. This problem has been rectified by routing these circuits thru qualified isolation devices. Based on the above, the staff concludes that this modification satisfies the physical separ-ation criteria of R.G.1.75 and is acceptable.
- 6. SSPS Train B Output 1 Cabinet The separation Group B SSPS Train B Output I cabinet MM-CP-13 con-tains separation group A (Train A associated) and separation group B (Train B and Train B associated) cables. The separation group A cable that is associated with the feedwater pump trip circuits is not properly separated from the other separation groups. This has been rectified (via a qualified isolation device) by changing the cable to separation group B and rerouting it to the isolation cab-inet MM-CP-470 where the signal is converted to separation group A via a qualified isolation device. Based on the above, the l
staff concludes that this modification satisfies the physical separ-ation criteria of R.G. 1.75 and is acceptable.
l 7. Auxillyy, Relay Rack 2 l
l The sepa' ration group A auxiliary relay 2 contains separation group A 1
1 (Train A associated) and separation group B (Train B associated) cables. The separation grot,p B cables that are associated with.the g'roup B Pressurizer Heaters, the Boric Acid Pump CS-P-3B, the power-operated Relief Valve RC-FCVL466B and the PORY Block Valve RC-V-124 are not properly separated from the otMr separation group. This has been rectified (via a qualified isolation device) by changing the cables to separation group A and verouting thetn to the isolation cabinet MM-CP-470 where the signals is converted to separation group B via a qualified isolation device. Based on the above, the staff concludes that this modification satisfies the physical separation criteria of R.G.1.75 and is acceptable, o
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- 8. Turbine Generator EHC Cabinet Bay 4 The separation group A EHC cabinet contains separation group A (Train A associated) cables and a separation group B, (Traia B associated) cable. ' The separation group B cable is associated with the turbine trip circuit and is not properly separated from-the other separation group. This will be rectified (via a qualified I' _ _ - _ _ _ _ _ _ _ _ -
-24 isolation device) by changing the cable to separation group A and rerouting it to the Isolation cabinet MM-CP-470 where the signal has been converted to separation group B via a qualified isolation device. Based on the above, the staff concludes that this modifi- '
i cation satisfies the physical separation criteria of R.G.1.75 and '
is acceptable.
- 9. Switching Station Relay Cabinets The separation group A switching station relay cabinets located in the unit I relay room contain separation group A (Train A associ-ated) and certain separation group B (Train B associated) cables, The switching station relay cabinets provide protective relaying for the preferred power supplies. The lockout relays associated with these systems provide contact inputs (tripping and block close) in the control schemer for 4160V preferred power supply breakers to buses E5 (Train A) and E6 (Train B). The cables from
- . the 4160V switchgears to these relay cabinets are designated
" Train A associated" and " Train B associated." The physical se-paration between these cables on their routing from switchgears to the relay cabinets fully satisfies separation criteria. How-ever, at the relay cabinets the interpanel wiring between various lockout relays within the relay cabinets is run in common wiring 4
harnesses. These wiring harnesses will have predominantly A as-sociated wiring along with very Ifmited B rssociated wiring (only fromBusE6). The applicant performed an analysis to demonstrate that failure modes such as open circuits, short circuits, ground !
and hot shorts on these circuits have no impact on the 4160V break-er control schemes and on other safety-related circuits which share raceways with t,hese circuits. The staff has reviewed the results of this analysis and concludes that the lack of separation between A associated and B associated wiring in the switching station relay l
cabinets will not prevent safety-related functions and will not affect other safety-related circuits and is acceptable.
l i
10 Input signal to Computer Intelligent Remote Terminal Unit (IRTU)
& An IRTU processes field input data and transmits this data to the 1
- 11. main computer for use by the video alarm system. Most of the ana- j
.)
log input signals provided by the field devices are processed thru i
, qualified isolation devices in the Westinghouse electronics cabinets prior to interfacing with the IRTU termination cabinets. However, ;
i other analog inputs which are provided thru transducers, digital inputs and input signals from RTDs and thermocouple are not pro-cessed thru qualified isolation devices. For these field input de-vices, the applicant has provided an analysis to demonstrate that i
there are no detrimental interactions between redundant separation
groups as a result of failures within the IRTV equipment. In this analysis the applicant included failure modes such as short circuit, open circuit, short to ground and application of maximum voltage !
within IRTU cabinets. However, credit was taken for fuses, cir-cuit breakers and current / voltage limiting devices to demonstrate that the above failure modes will not cause any detrimental impact on the field input devices. The staff informed the applicant that this was unacceptable.
The inadvertent application of 120V ac within the IRTU cabinets to the field input devices was discussed a number of times with the i
applicant. Based on these discussions it was determined that 120V ac could be inadvertently applied to some limited portions of the field input devices. Therefore, the staff required the applicant to perform a actual test to demonstrate that the maximum voltage and currents that are available in these cabinets have no adverse l
effect on field input devices (transducers, digital input devices, i RTDs and TCs) such that the class IE train with which the field
{
i devices are associated with will continue to perform the required J safety function before, during, and after the application of maxi-mum credible voltages and currents. The applicant has committed to ,
i perform these tests (before full power operation) and the staff will I 1
1 i
report the resolution of these items, after the test results are reviewed and evaluated, in a supplement to this report.
- 12. Turbine Building Instrument Rack )
i The applicant has stated that there are no electrical interconnect-tions between redundant divisions in this area and physical separ-ation criteria are satisfied. Therefore, this item has been deleted from this list.
- 13. Reactor Trip Switchgear Cabinet 1 The separation group B Reactor Trip Switchgear cabinet contains a separation group A (Train A associated) cable and separation group B (Train B and Train B associated) cables. The separation group A cable that is associated with the turbine trip circuit is not proper-ly separated from the other separation group. This has been recti-fied by changing the cable to separation group B (thru a qualified
., isolation device) and rerouting it to the Isolation cabinet MM-CP-470 where the signal is converted to separation group A via a qualified isolation device. Based on the above, the staff con-cludes that this modification satisfies the physical separation l
criteria of R.G.1.75 and is acceptable.
]
- 14. Reactor Coolant Pump Motors The separation group A RCP motor contains separation group A (Train A associated) cables and separation group B (Train B associated) cables. The separation group B cables are the 13.8 XV power feeder I
to the RCP. motor. The separation group A cables consist of the 480V power feeds to the oil lift pump and the motor space heaters and those circuits associated with the oil pressure / level switches and motor RTDs.
A postulated failure in these cables could impact the separation group A and the above mentioned specific separation group B cables, but it will not challenge other separation group B cables, as these cables are routed in dedicated raceways and do not interact with any other separation group B cables. Based on the above, the staff con-cludes that there is only a very remote chance that these associ-ated separation group B cables which are routed in dedicated race-
-, ways and are protected by two class IE devices in series, could challenge other separation group B circuits. Therefore, the staff finds this interface to be acceptable.
- 15. gessurizerHeaters Seventy-eight electrically independent pressurizer heaters are spaced around the bottom of the pressurizer with a separation of about four
inches between individual heaters. Fifteen of these heaters are powered from separation group B power supply and the remaining sixty-three are powered from separation group A power supplies. These pressure heater cables from the containment electrical penetrations are routed approximately 95% of their length in dedicated raceways.
Throughout the length, these raceways are separated in accordance with the recorrnendation of RG 1.75. No other cables share these
- r'a ceways .
1 In close proximity to the pressurizer (5-10 ft.) the separation group A cables and separation group B cables leave their dedicated raceways in order to terminate at the heater terminals under the pressurizer.
Because of the close location of the heater terminals, clearance be-tween these cables is limited to only 3-4 inches. The pressurizer heater cables in the vicinity of the pressurizer are provided with .;
l silicon rubber insulation with glass braid .iacket. This ensures safe l
, operation at high temperatures. In addition the pressurizer heater cables are protected by two class IE breakers in series. Based on the above, and in view of the fact that this congestion is unavoid-able in the Westinghouse standard design of the Pressurizer, the staff finds the 4" separation at tiie pressurizer heaters to be acceptable.
- 16. Reactor Incore Instrumentation Seal Table The separation group A seal table contains separation group A (Train A and Train A associated) cables and separation group B (Train B and Train B associated) cables. The seal table contains 58 thimbles for the fixed / moveable incore instrumentation. Each thimble also contains five fixed self-powered neutron detectors, one thermocouple (for enre exit temperature) and a guide tube for the moveable detector. The fixed detectors are equally divided between separation group A (Train A thermocouple and Train A as-sociated neutron detectors) and separation group B (Train B ther-mocouple and Train B associated neutron detectors).
Because of the congestion at the seal table, cables of redundant separation groups may be separated by only one inch. The voltage and current level in these circuits is of very low value (incore neutron detectors 5 x 10-9 to 600 x 10~9 amp; thermocouple
"., 0-51 mv) and there are no power supplies in the circuit to produce damaging fault currents.
These circuits, once they leave the con-gested area are run in separate solid cover trays or conduits.
Based on the low voltage and current level in these circuits and in view of the fact that this congestion is unavoidable in the Westing-house standard design of the guide tubes, the staff finds the above separation to be acceptable.
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l 1
8.3.2.2 Battery Supports The staff stated in the SER that an incompatibility between the battery rack !
and battery may cause cracking of the battery case. The cracking may be caused in part by inproper support at the battery stress points (the plate support bridge). It was concluded that pending staff confirmation that seismic testing I encompasses this stress-related aging of the battery, the staff considers this item to be acceptably res,olved. ,
1 By letter dated November 27, 1985, the applicant submitted additional informa-
{
tion on the battery rack construction design. The applicant stated that the i
cells sit on three steel stringers located under the cell center line and are !
15 inches from the center. This evenly distributes the cell weight to minimize stress on the cell (no excessive overhang of the battery cells) which was the primary reason for cracking of battery cells. In addition, test results show I that the seismic test of the batteries was successfully performed utilizing the I I
above rack design. This satisfies staff's concern and the staff considers this item to be acceptably resolved.
I
- 8. 3. 2. 4 Non-Safety Loads Powered From the DC Distribution System !
and Vital Inverters '
A 500-amp non-class 1E computer inverter is connected to class 1E battery B-1C.
Normally this inverter is fed from an ac source and when ac power is lost the battery supplies the inverter load. The class IE battery B-1C is capable of pro-viding power to this inverter for 15 minutes while supplying its safety-related
d loads. The inverter load is automatically disconnected by a circuit breaker in-ternal to the inverter from the class IE de system after the 15 minute period.
The design, which was used to disconnect the 500-amp load, did not meet class 1E protection system requirements. The staff informed the applicant that the design must meet class IE requirements. Subsequently the applicant committed to provide a separate trip circuit which meets all requirements of class IE cir-cuits. The staff stated in the SER that pending confirmation of implementation of the separate trip circuit, the design is acceptable.
Subsequently, a site trip and audit drawing review was conducted by the staff- on September 24 thru 26,1985. During the site visit the staff verified the imple-mentation of a separate, testable, class IE trip circuit which disconnects the non-class IE inverter from the class 1E de system after 15 minutes of discharge from the battery. Based on the above, the staff finds this item acceptably resolved. However, the surveillance requirements for the trip circuit will be included in the plant Technical Specifications.
8.3.3.3.1 Independence Between Class IE and Non-Class IE Circuits At Seabrook there are two safety related load trains (A and B), four safety re-lated instrumentation. channels, and the balance-of-plant (BOP) non-safety re-lated circuits. All BOP non-safety related circuits have been designated as as-sociated circuits. The associated circuits are subject to all requirements
placed on class IE circuits (such as cable derating, environmental qualifica-tion, flame retardance, splicing restrictions, and raceway fill). The staff stated in the SER that pending confirmation that the non-class IE circuits which are designated as associated circuits meet all the requirements of class 1 1
IE circuits (except for some items evaluated in the SER) the staff considers i
this item closed.
By letter dated November 27, 1985, the applicant submitted additional informa-tion on the above subject. Based on the review of the information provided by the applicant, the staff concludes that the associated circuits are uniquely identified and routed with those class 1E circuits with which they are associ-ated. Cables utilized for these associated circuits are specified, designed, manufactured and installed to the same criteria as class 1E cables. The same procedures are used for the installation and inspection of safety and non-safety cables and cable terminations that enter, leave, transverse or are within the Nuclear Island, and cables that are contained outside the Nuclear Island to meet
-. all the requirements of class IE with the exception of QC inspection.
The above ,
satisfies the guidelines outlined in position C.4 of R.G.1.75 and is accept- l l
able.
8.3.3.6.3 Compliance With R.G.1,63 Circuit Protection for Control Power (ac and dc) Circuits:
For control circuits which are powered from limited capacity power sources, such as control power transformers, the applicant has indicated that dual protection
_-------,,-_--_--------_----.u-- .a.------- ----__----
to protect the penetration is not needed because the short circuit versus time capacity of their power sources is within the penetration capabilities. The :
staff stated in the SER that pending confirmation of this capability this item is considered acceptable.
By letter dated November 27, 1985, the applicant provided additional informa-tion to justify not providing backup protection for the 120V control cir-cuits powered from control power transformers. The applicant has stated that the fault currents are limited to below the continuous current carrying capa-bility of the penetration conductors, due to the impedance of the control trans-fonners. For these circuits, the staff believes that although the impedance of l:
the control transformer limits the short circuit current to below the continuous current carrying capability of the penetration conductors, these enntrol trans-formers cannot limit the short circuit current indefinitely. Subsequently, by letter dated March 19, 1986, the applicant further justified its position for i providing single protection for control transfonner circuits. The apolicant in-
,' i dicated that any fault on the control power transformer power circuits will l
appear as a ground fault on the associated 480V system. The Seabrook station 480V system is a high resistance grounded system with a maximum ground fault current of 2.92 amps, which is below the continuous current carrying capability of the penetration conductors.
-m \
Based on the above, the staff concludes that one line of overcurrent protection for 120-V control circuits powered from control power transformer is acceptable.
i j
I ENCLOSURE 2 EICSB/DPA INPUT j
-PLANT: Seabrook Station LICENSEE: Public Service of New Hampshire LICENSEE STATUS: OL SER
SUBJECT:
Supplemental Safety Evaluation Report PERFORMANCE PARAMETERS:
(1) Management Involvement in Assuring Ouality (2) Approach to Resolution of Technical Issues From a Safety Standpoint (3) Response to NRC Initiatives (4) Staffing (Including Management)
(5) Reporting and Analysis of Reportable Events (6) Training and Qualification Effectiveness (7) Any Other SALP Functional Area PERFORMANCE NARRATIVE DESCRIPTION OF CATEGORY /
PARAMETER APPLICANT / LICENSEE'S PERFORMANCE RATING 1 PSNH management stationed at Bethesda 1 was instrumental in resolution of staff's concerns by arranging meetings, transmitting documents and timely '
follow-up of various items.
2 PSNH technical staff was responsive to 1 all safety issues identified by the
, staff and resolved it in a professional
. and regulatory manner.
3 PSNH technical staff and their repre- 1 sentatives at Bethesda quickly'and pro-fessionally responded to staff's initia- ,
i tives and concerns. J 4 thru 7 N/A OVERALL APPLICANT / LICENSEE PERFORMANCE RATING 1 I
E___________ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ . _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ . _ . _ _ _ --