ML19323A759

Responds to IE Bulletin 80-03.American Air Filter Type II,2- Inch Tray Adsorber Cells Are Utilized at Facility.Spot Welds Are Used to Secure Perforated Screen to Cell Casing.Insp of Warehouse Storage Cells Did Not Identify Screen Deformatio

ML19323A759
Person / Time
Site:	Millstone
Issue date:	03/24/1980
From:	Counsil W, Fee W NORTHEAST NUCLEAR ENERGY CO.
To:	Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
IEB-80-03, IEB-80-3, NUDOCS 8005050391
Download: ML19323A759 (3)

Text

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1 March 24,1980 Docket No. 50-336 Mr. Boyce H. Grier, Director Region I Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, PA 19406 1

Reference:

(1) B.H. Grier letter to W.G. Counsil dated February 6,1980, forwarding I&E Bulletin No. 80-03 Gentlemen:

Millstone Nuclear Power Station, Unit No. 2 Response to I&E Bulletin No. 80-03 Reference (1) requested Northeast Nuclear Energy Company (NNECO) conduct an inspection of standard type II, 2 inch tray adsorber cells presently utilized in various plant ventilation syste..:s. In particular, the NRC 1.taff requested the following information with regard to this inspection:

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1) The manufacturer and cell design presently in use and the systems containing the cells.

2) Examine the rivet spacing ' securing the cell casing to the perforated screen which may result in separation of the screen and cell housing and adsorber cell or filter housing deformation causing a loss of charcoal and/or channeling.

3) Describe the manner cf the visual inspection performed and determine if the charcoal adsorber cells in use, or proposed  :

for use, have the potential for a loss of charcoal incidental '

to handling, storage or use (as appropriate). In addition, the NRC staff requested that this information be submitted within 45 day; of the date of reference (1).

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In response to the above items, NNECo provides the following:

ITEM 1 i

Millstone Unit 2 utilizes the type II, 2 inch tray adsorber cells

manufactured by the American Air Filter Corporation which are very similar to the model ASK 1743-735A manufactured by Mine Safety

Appliance Corporation. These filters are used in the two ESF

systems; the Enclosure Building filtration system and the Control

. . Room filtration system.

'l ITEM 2 All of the type II, 2 inch cells used in Unit 2 utilize spot welds to secure the perforated screen to the cell casing rather than rivets. The spot welds are spaced fron between 1/2 inch to 2 inches apart and are used around the complete screen / casing perimeter.

i ITEM 3 A visual inspection consisted of a physical examination of the cells in warehouse storage which had been refilled with charcoal by Charcoal Service Corporation, but which had been in use at Millstone Unit 2 previously. There were no indications of screen and housing I

separation of deformation (sagging) which could result in loss of j charcoal and/or channeling.

l Inservice cells were not available for inspection at this time 1 since it would be required to take the ventilation system out of service in order to remove the cells for inspection. It is felt i

that Millstone Unit 2 cells presently in service do not have the same deficiencies as the riveted cells described in reference (1) for the following reasons:

1) In addition to spot welding the screen to the cell casing at intervals of 1/2 inch to 2 inches, four equally spaced reinforcing rods, are installed thru the screen and cell casing and secured s with washers and nuts.

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2) Charcoal Services Corporation performs complete visual inspections of all cells sent to them for charcoal change-out. This l inspection is performed before any work is begun to recharge i the cell and examine the cell for any structural deficiencies that may have developed in service. These preliminary inspections have shown no deficiencies on any Millstone Unit 2, 2 inch i adsorber cells.

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It is planned to change-out the ESF ventilation cells at the end of April and the remaining cells in June of this year. A complete inspection will be performed on these cells at Millstone Unit No. 2 in accordance with Section 5 of ANSI N510-1975 at that time.

We trust you find this information satisfactory to disposition the Reference (1) concerns. We remain available should the Staff require clarification of any of the above information.

Very truly yours, NORTHEAST NUCLEAR ENERGY COMPANY W. GVCounsil Vice President

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By:

W. F. Fee Vice President l