ML18086A965
| ML18086A965 | |
| Person / Time | |
|---|---|
| Site: | Salem  |
| Issue date: | 09/02/1981 |
| From: | Mittl R Public Service Enterprise Group |
| To: | Varga S Office of Nuclear Reactor Regulation |
| References | |
| GL-81-04, GL-81-4, NUDOCS 8110130203 | |
| Download: ML18086A965 (5) | |
Text
e 0 PS~G Public Service Electric and Gas Company 80 Park Plaza, T160 Newark, N.J. 07101 201/430-8217 Robert L. Mittl General Manager - Licensing and Environment Director of Nuclear Reactor Regulation U.S. Nuclear Regulatory Coll).Illission 7920 Norfolk Avenue Bethesda, MD 20014 September 2, 1981 Attention:
Mr. Steven A. Varga, Chief Operating Reactors Branch 1 Division of Licensing Gentlemen:
EMERGENCY PROCEDURES AND TRAINING FOR STATION BLACK-OUT EVENTS NO. 1 AND 2 UNITS SALEM NUCLEAR GENERATING STATION DOCKET NO. 50-272 AND 50-311 In a previous letter sent to you on August 3, 1981, concerning this same topic, we indicated that some additional information would be supplied by September 1, 1981.
This information would address specific items from the NRG Generic Letter 81-04 that would not be impacted by the Owners Group efforts.
The Owners Group has recently conducted a meeting on the draft.procedure guidelines for "loss of all AC events" to :resolve comments and f9rmulate a final procedure.
Therefore, a final response to this item is not possible at this time.
However:, some general information can be provided.
Item A The actions necessary and equipment available to maintain the reactor coolant inventory and heat removal with only DC power available, including consideration of the unavailability of auxiliary systems such as ventilation and component cooling.
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U.S. Nuclear Regulatory Commission 9/2/81 The turbine driven auxiliary f eedwater pump would be utilized for heat removal along with the steam atmospheric relief valves or steam safety relief valves.
The turbine driven pump requires DC power to be oper-ational and is not dependent on component cooling.
The steam atmospheric relief valves can be manually operated via handwheels.
The steam safety relief valves are pressure actuated, spring control, valves.
Required instrumentation is powered by vital instrument bus inverters from batteries.
Startup testing of Unit 2 included maintenance of natural circulation conditions without AC power.
The startup tests indicated that the plant a.an* be maintained in. a *safe condition for a limited time during a total loss of AC power.
This includes operation without ventilation system fans.
Additional information will be provided following a review of the Westinghouse Owners Group Procedure Guidelines.
Item B The estimated time avail.able to restore AC power and its basis.
The existing design and training provisions at Salem were developed to address the loss of off site AC power and not a total loss of station AC power.
We currently see no credible mechanism which would result in the total loss of offsite and onsite AC power.
The diesel-generators are activated by a "DC based" control power system.
There are three diesel-generators for each unit which are automatically started upon a blackout signal.
The diesels are started with all loads connected in sequence within 30 seconds.
This is the design basis for Salem.
Descriptive information is contained in FSAR Section 8.4.
A failure of one diesel does not affect plant safety.
There are three separate batteries, one for each diesel.
There are also sepa-rate rooms for the diesels and ventilation systems.
It is not possible to establish a time frame for restoration of AC power other than the design basis. Postulated hypothetical events causing such conditions are varied with potentially different restoration times for each.
AC power can also be restored eventually from the offsite sources and the gas turbine at the plant.
Additional information will be provided following a review of the Westinghouse Owners Group Procedure Guidelines.
U.S. Nuclear Regulatory Commission Item C The actions for restoring off site AC power in the event of a loss of the grid.
9/2/81 Since the nature of a system-wide disturbance and the exact separation cannot be predicted, restoration procedures can be used only as guides.
Salem is connected to and receives off-site power from the bulk system by 3-500 kV transmission lines.
If a system disturbance causes all or part of the 500 kV transmission system grid to trip-out and the under-l;';i..ng_. areas are also affected, it is not likely that all the 500 kV circuits can be restored to service immediately.
Use of available interconnection power sources can be of significant aid during the restoration process.
The Interconnection Dispatcher is responsible for coordinating the restoration of the 500 kV system.
As soon as sufficient load and generation have been restored to the affected area to safely absorb the heavy charging current generated by the 500 kV lines, the circuits will be restored one at a time.
The following general rules apply to energizing 500 kV lines:
- a.
Line sections are energized one at a time.
- b.
The bus voltage used to energize a line should be below nominal if possible.
- c.
Energizing limitations must be_carefully followed to minimize effects of switching surges and steady-state overvoltages.
This includes assurance of a firm power system behind energizing circuit breakers.
Restoration of the 500 kV system will proceed in parallel with restora-tion of the underlying bulk power system.
Item D The actions for restoring off site AC power when its loss is due to postulated onsite equipment failures.
There are two independent offsite power sources for the Salem plant.
They interface with the onsite 4 kV vital power system through two separate station power transformers and associated circuit breakers.
The configuration is shown in FSAR Sections 8.2 and 8.3.
The system has been designed so that individual equipment failures do not result in a loss of offsite power.
Postulated hypothetical events causing such conditions are varied resulting in different restoration actions for each.
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U.S. Nuclear Regulatory Commission Additional information will be provided following a review of the Westinghouse Owners Group Procedure Guidelines.
Item E The actions necessary to restore emergency onsite AC power.
The actions required to restart diesel-generators should include consideration of loading sequence and the unavailability of AC power.
9/2/81 The three diesel-generators are automatically started upon a blackout signal which is dependent only upofi* tha:: availability of DC power.
The operators are aware of load limitations when manually starting diesels and when loading equipment on the vital buses.
Instructions have been written which enable the operators to start the diesel-generators under postulated fire conditions.
Only two of the three diesels are required. Postulated hypothetical events causing conditions requiring diesel restart are varied due to any number of components that may be the cause of a diesel not starting; this will result in different restart actions.
Additional information will be provided following a review of the Westinghouse Owners Group Procedure Guidelines.
Item F Consideration of the availability of emergency lighting, and any actions required to provide such lighting, in equipment areas where operator or maintenance actions may be necessary.
The emergency lighting system at Salem is powered from inverters with battery backup.
Lighting has been provided throughout various areas of the plant where operator action may be required.
In addition to the emergency lighting system, 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> battery pack lights have been provided in selected areas of the plant as part of the fire protection program.
Sufficient lighting exists for postulated loss of AC power events.
No action is required for these lights to be operational.
Item G Precautions to prevent equipment damage during the return to normal operating conditions following restoration of AC power.
For example, the limitations and operating sequence requirements which must be followed to restart the reactor coolant pumps following an extended loss of seal injection water should be considered in the recovery procedures.
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U.S. Nuclear Regulatory Commission This item will be addressed later following a review of the Westinghouse Owners Group Procedure Guidelines.
9/2/81 The Westinghouse Owners Group Procedure Guidelines for a "Total Loss of All AC Power Event" is expected to be finalized in mid-September.
We will incorporate any applicable recommendations into specific plant procedures in accordance with the implementation schedule of NUREG-0737, item I.G.l as specified in the Westinghouse Owners Group letter dated August 7, 1981 (OG-63).
We believe that our training program can efficiently address any new procedural requirements that may be developed.
Should you have any questions in this regard, do not hesitate to contftct us.
Very truly yours, CC Mr. Leif Norrholm Senior Resident Inspector