ML20028F079
| ML20028F079 | |
| Person / Time | |
|---|---|
| Site: | Seabrook  |
| Issue date: | 01/26/1983 |
| From: | Devincentis J PUBLIC SERVICE CO. OF NEW HAMPSHIRE, YANKEE ATOMIC ELECTRIC CO. |
| To: | Knighton G Office of Nuclear Reactor Regulation |
| References | |
| SBN-437, NUDOCS 8301310125 | |
| Download: ML20028F079 (3) | |
Text
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r s u a su m lPUBLIC SERVICE E.,*.z i., Office:
Companyof NewHampeNee 1671 Worcester Road Framingham, Massachusetts 01701 (617) - 872 - 8100 January 26, 1983 SBN-437 T. F. B7.1.2 United States Nuclear Regulatory Commission Washington, D. C. 20555 Attention:
Mr. George W. Knighton, Chief Licensing Branch No. 3 Division of Licensing
References:
(a) Construction Permits CPPR-135 and CPPR-336, Docket Nos. 50-443 and 50-444 (b) PSNH Letter SBN-289, dated July 2, 1982, "FSAR Section 8, Open Item List, Power Systems Branch (Electrical)"
J. DeVincentis to F. Miraglia
Subject:
Open Item Responses ; (Power Systems Branch)
Doct Sir:
We have enclosed responses to the following open items which were discussed with representatives of the NRC Staff in a meeting conducted on January 18, 1983.
NRC Branch SRP Section Comments PSB (Electrical) 8.3.1.1.1 - Time delay See attached revised
'or second level under-FSAR Page 8.3-5 voltage protection PSB (Electrical) 8.3.2.4 - Tripping of See attached revised Non-Class 1E Inverter I-2A response to Open Item 20 The enclosed responses will be included in a future Amendment to the OL Application.
Very truly yours, t
l YANKEE ATOMIC ELECTRIC COMPANY
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8301310125 830126 I
John DeVincentis PDR ADOCK 05000 for : Project Manager i
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cc: Atomic Safety and Licensing Board Service List L
Y Rev. 1/27/83-OPEN ITEM 20 The NRC requested that the load profiles for the safety-related batteries be included in the FSAR.
RESPONSE
The FSAR has been revised accordingly to incorporate these (12/82) profiles.
RESPONSE
The following response is provided to satisfy further questions (1/83) in regard to the connection of non-safety-related loads to the safety-related batteries.
It is pointed out that these loads are connected to the de buses with Class 1E breakers (cefer to RAI 430.149).
Figure 8.3-37 shows two non-safety-related loads on the safety-related de buses: Computer Inverter I-2A and Distribution Panel PP-llllB. Computer Inverter I-2A is included in the load profiles given in Figure 8.3-51.
The attached Table 8.3-5 has been revised to list Computer Inverter 1-2A as a load on the safety-related batteries. Distribution Panel PP-1111B was not included in the load profile given in Figure 8.3-52, because the panel feed was tripped on an accident signal.
Since the panel feed will no longer be tripped (see response to RAI 430.30), Table 8.3-5 and Figure 8.3-52 will be updated when the actual panel load is finalized to include Distribution Panel PP-1111B as a load on the safety-related batteries. The estimated panel load is less than 10A.
Table 8.3-5 and Figure 8.3-51 show Computer Inverter 1-2A tripped off of the de bus after 15 minutes. Presently, this trip of the internal inverter de circuit breaker is initiated from within the inverter by a timing relay which monitors the time the inverter draws power from the safety battery. The actual power to energize the shunt trip. coil for the de circuit breaker is from an internal de control power supply which has an internal battery backup.
A separate safety-related trip circuit will be added to trip in
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15 minutes the Class 1E breaker on de Bus llc which feeds Inverter I-2A.
This circuit, which monitors the time the l
inverter draws power from the safety-related battery, will be testable and will meet all the requirements of a Class 1E c ircuit. The timing circuit will be powered from de Bus 11C.
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7
4 SB 1 6 2 FSAR After synchronism is verified by the synch scope, the transfer is initiated by manually closing (by means of the MCB mounted control switch) the desired source breaker, which automatically trips the other source breaker.
4.
Undervoltage and Load Shedding (a) First Level.Undervoltage Protection Upon loss of voltage on a 4.16 kV emergency bus, 1.2 second s a r e allowed for the au t oma t ic trans fer described in Subsect ion 8.3.1.1.b. 3(c) above to be completed.
If undervoltage persists af ter this time, the first level of undervoltage protection will be activated.
We following actions occur simultaneous 1yr (a)
Bus loads are tripped as required, i
(b)
UAT and RAT breakers are tripped to isolate the bus, (c) Automatic transfer schemes are disabled, and (d)
Standby power supply (diesel generator) is started and subsequently connected to the emergency bus as described in Subsection 8.3.1.le.
On an emergency bus, if the UAT incoming line breaker trips open and the RAT source is unavailable, the trans fer schemes are not initiated. W e standby power supply (diesel generator) is immediately started and connected the emergency bus as described in Subsection 8.3.1.le.
to (b) Second Level Undervoltage Protecti_on*
If the voltage on a 4.16 kV emergency bus is below that required to ensure the continued operation of safety related equipment, the second level undervoltage protection scheme is activated.
If the activation occurs coincidently with an accident signal, then the UAT and_ RAT incoming ~
line breakers are automatically tripped /I This will result in total loss of voltage to the bus with ensuing actions described in Subsection 8.3.1.1.b.4(a) above.
If the second level undervoltage protection scheme is activated without the coincident presence of an accident signal, then only an alarm is received.
Established plant procedures require the operator to take specific
- Second level undervoltage protect ion has not yet been incorporated into k'
the FSAR drawings.
Details will be furnished later.
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