ML13333A421
| ML13333A421 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 10/05/1979 |
| From: | Haynes J SOUTHERN CALIFORNIA EDISON CO. |
| To: | Ziemann D Office of Nuclear Reactor Regulation |
| References | |
| TASK-09-01, TASK-9-1, TASK-RR NUDOCS 7910220328 | |
| Download: ML13333A421 (4) | |
Text
Southern California Edison Company r
P. 0.
BOX 800 2244 WALNUT GROVE AVENUE ROSEMEAD, CALIFORNIA 91770 October 5, 1979 Director of Nuclear Reactor Regulation Attention:
Mr.
D. L. Ziemann, Chief Operating Reactors Branch #2 Division of Operating Reactors U.S. Nuclear Regulatory Commission Washington, D.C.
20555 Gentlemen:
Subject:
Docket No.
50-206 Systematic Evaluation Program San Onofre Nuclear Generating Station Unit 1 On August 10, 1979, Mr. Fletcher of the NRC staff telecopied to Southern California Edison a request for additional information for Systematic Evaluation Program (SEP) Topic IX-1, Fuel Storage. Responses to those questions were provided to Mr. Fletcher via telephone on September 28, 1979.
The purpose of this letter is to document the responses to the questions.
That information is provided as an enclosure to this letter.
If you have any questions concerning this information, please contact me.
Very truly yours, J. G. Ha es Chief of Nuclear Engineering Enclosure 7910220
Enclosure Response to Questions on Fuel Storage SEP Topic IX-1 Question 1 Can the failure of any piping system result in draining the spent fuel pool below the level of the top of the stored fuel (consider siphoning)?
Response
No. There are three lines which terminate below the normal water level of the spent fuel pool.
The normal suction line (3100-6"-151R) of the spent fuel pit pump, G-5, is approximately 8' below the surface. There is an alternate suction line (310OA-4"-151R) for this pump used to dewater the spent fuel pit.
This alternate line takes suction near the bottom of the pool.
However, there is a high point vent, normally open, which prevents siphoning in the unlikely event the line should break.
The spent fuel pit heat exchanger return line (3086-6"-151R) terminates an estimated 10' below the normal surface.
Failure of any piping system would not permit the water level to drop to less than 15'7" (approximately) above the top.of the stored spent fuel.
Question 2 What instrumentation and alarms are associated with the spent fuel pool?
Response
LC 615 provides a high and low water level alarm to the control room.
Normal water depth is 39'.
The high and low level alarms are set at 39'2" and 38'10" respectively. The low level alarm provides a minimum of 25'5" of water above the top of the stored spent fuel.
TIC 615 provides a high temperature alarm at 125 0F.
There is an area radiation monitor in the vicinity of the spent fuel pool which alarms in the control room.
Question 3 List all the sources of makeup water to the pool (include "Damage Control Measure" sources such as fire hoses).
Provide comments regarding the ability of these sources to survive a seismic event (SSE).
Response
The following information is contained in a report, "Spent Fuel Shipping Cask Handling", sent to Mr. K. R. Goller of the NRC on March 21, 1975. Figure 12 from that report is attached as a visual summary of the various water sources.
-2 Makeup water for the spent fuel pool can be provided via the spent fuel cooling water return line by either the refueling water filter pump (80 gpm) from the refueling water storage tank (240,000 gallons) or the primary plant makeup pumps (2 at 100 gpm each) from the primary plant makeup tank (150,000 gallons).
In addition the fire protection water system could also be utilized to provide makeup water to the spent fuel pool.
The fire protection water pumps (2 at 1000 gpm each) could provide makeup water from the service water reservoir (3,000,000 gallons) or the circulating water system (through the 1000 gpm screen wash pumps) via hydrants located at strategic points in the plant and fire hoses (100 gpm each).
Makeup water to the spent fuel pool could also be provided by gravity flow from the condensate storage tank (240,000 gallons) through the fill/drain connection with fire hoses.
The above water sources have the following seismic category.
Equipment Seismic Category Spent fuel pool A
Refueling water filter pump C
Refueling water storage tank A
Primary plant makeup pumps Not available Primary plant makeup tank B
Fire protection water pumps C
Service water reservoir A
Screen wash pumps C
Fire hydrant system C
Condensate storage tank B
The piping systems associated with these water sources are non-category A.
Question 4 Discuss the ability of the plant systems and procedural controls to detect a low fuel pool level following a seismic event.
Response
Operating procedure S-3-5.27, Earthquake, provides that a thorough examination be made of the new and spent fuel storage building. This inspection would include visual inspection of the spent fuel pool and inspection for pool leaks using the leak detection features of the pool.
,L MAKEUP
- *&FUELING WATER STORAGE TANK 240,000 GAL.
REFUELING WAVCER FILTER PUMP 80 GPM PRIMARY PLANT.
MAKEUP VEATER SPN FUL IE CRE TANK5000 GL PRIMARY PLANT.
P00 A
AT WFMAKEUP PUMPS (2) 100 GPM EACH EMERGENCY MAKEUP CONSTRAINED BY 100 GPM CAR/FIREHOSE SERVICE WATER RESERVOIR FIRE 3,000,000 GAL.
PUMPS (2)
10000 GPM LEAK
.E.EC CONDSYSTEM FIREH OSE LEAKSE DETETIO SPNTFENT FULIRTMAEU ASRND LEAK DETECIONESYSTE FF GURE 2.