ML19345G136
| ML19345G136 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 08/18/1976 |
| From: | Sewell R CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| IEB-76-07, IEB-76-7, NUDOCS 8103060709 | |
| Download: ML19345G136 (2) | |
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August 18, 1976 Mr James G. Keppler US Nuclear Regulatory Commission T99 Roosevelt Road Glen Ellyn, IL 60137 DOCKET 50-155, LICENSE DPR BIG ROCK POINT PLANT The following information is provided as requested by Bulletin "o 76-07 trans-mitted by your letter dated July 28, 1976. The questions are repeated to facilitate our responses.
Question 1(a) - Have you made, or do you plan to make, modifications to the hoist control for your installed cranes similar to the described modifications?
Answer Modifications to hoist brake system of the reactor building crane are planned. These modifications are not similar to those described in Bulletin 76-07 No modifications have been cade to the hoist controls of the loading dock crane.
Question 1(b) - If such modifications have been ede, or are planned, identify changes required in brake power and control circuitry.
Answer
- Modification involves replacing existing d-c solenoid Westing-house SAR 1355 holding brake and adding a redundant second brake on undriven end of hoist drum. It is proposed that the new brakes be Whiting 13" SESA a-c solenoid brakes, with rated torque 550 lbf(ft). These brakes are self-adjusting and auto-matically reset whether. electrically or manually operated. Con-trol circuit modification requires only the elimination of the a-c/d-c transformer / rectifier assembly. The existing a-c power rated contactors supplied with the existing crane installation vill not be changed. The electrical load on the existing contacts associated with the new a-c solenoid brakes vill be equal to or less than their rated capacity.
Question 1(c) - What steps have been taken or are planned to provide assurance C-that brake power contactors are adequate for the service?
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2 Answer
- Existing brake power contactors have given satisfactory service since initial installation. There has been no evidence of load coast or overtravel. During upcoming crane modification, all contactors for the reactor building crane brake vill be in-spected for wear or defects.
Question 2
- If modifications are planned, provide the schedule for comple-tion and a brief description of your plans for design review and functional testing.
Answer
- Schedule for Completion: The schedule for completion, based on Whiting Corporation's delivery of parts and material, is Septem-ber of 1977 This includes construction and start-up testing and is based on issuing the crane modification purchase order by early October. Attempts are being made to accelerate this schedule.
Design Review: The modification of the cranc, including all design, procurement, and construction vill be accomplished under
. the Catalytic, Inc Quality Assurance Program, including the Catalytic, Inc Nuclear Engineering Design Procedures Manual.
Functional Testing: New brakes vill be tested.for load rating certification and electric and manual operation at rated load C.,
by manufacturer. Upon completion of inspection and overhaul, if necessary, of hoist contactors, hoist controls including-brakes will be tested for their operation without load.
De-fective operation vill be corrected. Under controlled condi-tions, brakes will then be tested with crane rated load. These tests will include:
l.
Both brakes checked for independent operation.
2.
Observation of contactors for arcing or defects.
3 Observation of response time and travel of load during braking.
Defective conditions will be corrected and tests repeated, if necessary.
Ralph B. Sewell (Signed)
Ralph B. Sevell Nuclear Licensing Administrator CC: Director, Div of Reactor Inspection Programs USNRC, Washington, DC