ML19340E986
| ML19340E986 | |
| Person / Time | |
|---|---|
| Site: | Cooper  |
| Issue date: | 01/07/1981 |
| From: | Pilant J NEBRASKA PUBLIC POWER DISTRICT |
| To: | Eisenhut D Office of Nuclear Reactor Regulation |
| References | |
| RTR-NUREG-0619, RTR-NUREG-619 LQA8100051, TAC-43402, NUDOCS 8101160448 | |
| Download: ML19340E986 (2) | |
Text
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COOPER NUCLEAR STATION V'b '
Nebraska Public Power District
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'his LQA8100051 gg_g g January 7, 1981 2
Mr. Darrell G. Eisenhut, Director Division of Licensing Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Washington, D.C.
20555 Subj ect : Response to NUREG 0619-BWR Feedwater Nozzle and Control Rod Drive Return Line Nozzle Cracking
Dear Sir:
Responses to NUREG 0619-Part 1-Feedwater Nozzles and Part II-Control Rod Drive Return Line Nozzles are presented below:
Part I-Feedwater Nozzles During the spring 1980 refueling and maintenance outage, the inter-ference-fit feedwater spargers were removed, the nozzle cladding was removed, and the nozzle inspected. Triple-thermal sleeve, double-piston ring spargers were then installed. The existing feedwater flow control system provided satisfactory low-flow control so modification of the low-flow control was not necessary.
Based on the ratio of RWCU flow to feedwater flow of 1 to 100, rerouting of the RWCU system is not con-sidered applicable to CNS. No other system changes were deemed neces-i sary.
Existing procedures were considered satisfactory and no changes were made. NDE inspection as required by Table 2 and Section 4.3.2.4 shall be implemented.
Part II-Control Rod Drive Return Line Nozzle During the fall 1977 Refueling and Maintenance Outage the CRD System was tested for proper operation with the return line valved out of service.
l Satisfactory results from that test allowed the cutting and capping of j
the return line at the vessel. Dye penetrant inspections of the return line nozzle and surrounding vessel wall revealed no cracks.
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8.10))60 N
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Mr. Darrell G. Eisenhut January 7, 1981 Page 2.
l A return flow capacity test was performed in April 1980 by special procedure to demonstrate CRD System capability to supply water to the vessel and was based upon G.E. test instructions. Concurrent two pump operation was demonstrated r.c normal reactor operating pressure.
The test results indicated CRD System capacity below the G.E. projected valves for CNS but still within the low region of the accepta.ce cri-teria. A revised test pr.ocedure is being prepared that will optimize the measured CRD System flow and will be performed in the spring of 1981. From the results of this test, a better determination with respect to installation of a CRD return line can be made.
To resolve the concern over the reverse flow condition in the CRD System, a CRD System modification is planned for the next refueling and maintenance outage to install equalizing valves in the CRD System and to replace all carbon steel pipe with stainless steel pipe in the areas of reverse flow. These modifications will complete the actions required in this area of concern.
If you have any questions regarding this response, please contact me.
Sincerely, 2
J.
Pilant Director of Licensing and Quality Assurance JMP:PLB:cg l
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