ML20086E750
| ML20086E750 | |
| Person / Time | |
|---|---|
| Site: | Fort Saint Vrain  |
| Issue date: | 10/20/1972 |
| From: | Walker R PUBLIC SERVICE CO. OF COLORADO |
| To: | Kruesi F US ATOMIC ENERGY COMMISSION (AEC) |
| Shared Package | |
| ML20086E708 | List: |
| References | |
| 10CFR-050.55E, 10CFR-50.55E, NUDOCS 8312070508 | |
| Download: ML20086E750 (5) | |
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P.O. BOX 840 DENVER, COLORADO E0201 An Rx October 20, 1972 Mr. F. E. Kruesi Directorate of Regulatory Operations United States Atomic Energy Commission Washington, D. C.
'20545 Subjecc: Deficiency Report 10 CFR 50 Diesel-Generator Cooling Water Fort St. Vrain Station
Dear Mr. Kruesi:
Pursuant to the reporting requirements of 10 CFR 50, Part 50.55, we are submitting herewith twenty copies of the subject report involving the back-up cooling water to the emergency diesel-generators at the Fort St. Vrain Station.
The units are presently in service with a continuous flow of water through the coolers from the back-up (fire-water) system.
We trust this report will provide you with sufficient information and will fulfill the requirements of 10 CFR 50 Regulations.
Very truly yours, R.7. Wallw R. F. Walker, Vice President Engineering and Planning Electric Department RFW/FEStals cc: Mr. John Flora Director, Region IV Denver
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DEFICIENCY REPORT 10 CFR 50 - Part 50.55 Facility: Fort St. Vrain Nuclear Generating Station
Subject:
Standby Diesel-Generators Date:
October 1972 1.
General Conditions The cooling water to the Diesel-Generator heat exchangers is normally from the service water system, but there is an emergency back-up supply from the fire-water system.
There are stop check valves in the fire-water supply lines to prevent service water entering these lines.
Diesel-Generator set "A" was being test run af ter reassembly from a dismantling to check cylinder and head condition. As the service water system to the Diesels was temporarily out-of-service, the run was attempted using the back-up cooling supply.
2.
Cause Determination Shortly after startup the engines tripped on high coolant temperature. Disassembly of the back-up system supply valves revealed that, due to the valve design, the valves were stuck closed.
The sticking was caused by small foreign particles jamming between the valve sleeve and valve body. Foreign particles of this size are common to water from cooling tower systems. This type of valve will not give satisf actory service in this application with this type of water supply.
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Remedial Action l
To ensure a supply of cooling water while new valves are L
being procured, the inner disc and sleeve were removed from the-back-up wupply lines to both Diesel-Generator sets "A" and. "B".
i The ordered replacemen't is'a, swing check type of valve,.
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.not prone to :failur.e.with a cooling tower water supply.
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Separate stop' valves are also being provided; i
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DEFICIENCY REPORT 10 CFR 50 - Part 50.55 Facility:
Fort St. Vrain Nuclear Generating Station
Subject:
Standby Diesel-Cenerators Date:
October 1972 1.
General Conditions The cooling water.to the Diesel-Generator heat exchangers is normally from the service water system, but there is an emergency back-up supply f rom the fire-water sys tem.
There are stop check valves in the fire-water supply lines to prevent service water entering these lines.
Diesel-Generator set "A" was being test run af ter reassembly from a dismantling to check cylinder and head condition. As the service water system to the Diesels was temporarily out-of-service,
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the run was attempted using the back-up cooling supply.
2'.
C$use Determination Shortly after startup the engines tripped on high coolant temperature. Disassembly of the back-up system supply valves revealed that, due to the valve design, the valves were stuck closed.
The sticking was caused by small foreign particles jamming between the valve sleeve and valve body. Foreign particles of this size are common to water from cooling tower systems. This type of valve will not give satisfactory service in this application with this, type of water supply.
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Remedfol Action To ensure a supply of cooling water while new valves _are being procured, the inner disc and sleeve were removed from the back-up wupply lines to both Diesel-Generator sets "A" and "B".
.The ordered replacement is a swing check type of valve, not prone to fallare with a cooling tower water supply.
Separate stop valves are also being provided.
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