ML19329E374
| ML19329E374 | |
| Person / Time | |
|---|---|
| Site: | Midland |
| Issue date: | 06/10/1975 |
| From: | Howell S CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| IEB-75-05, IEB-75-5, NUDOCS 8006120687 | |
| Download: ML19329E374 (4) | |
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o.n.r. ome..: 2 2 w.. acneg.n av.nu s ca.on. wen g.n 4 2o. Ar.. Cod. SW 788 0SSO June 10, 1975 MIDLAND PLANT' 50-329 & 50-330 Response to IE Bulletin 75-05 on Operability of Category I Hydraulic Shock and Sway Suppressors File: 0505.2 Serial: 16015 J. G. Keppler THIS D0CUMENT CONTAINS Regional Director
' POOR QUALITY PAGES US Nuclear Regulatory Commission T99 Roosevelt Road Glen Ellyn, IL 60137
Dear Mr. Keppler:
i Your letter of April lt, 1975 requested infor=ation on the design requirements of hydraulic suppressors being employed on the Midland Plants. Please be advised'that no Seismic Category I hydraulic shock and svay suppressors for piping systems at Midland have been released for design and manufacture. We are currently developing a specification for standard piping system suppressors.
To date only specially designed reactor coolant pu=p (RCP) LOCA restraints and seismic snubbers, to limit pump move ent, have been purchased for Midland.
The following general responses to your questions on standard piping system suppressors to be supplied in the future are provided along with the information available at the current state of design for the specially designed RCP LOCA snubbers.
Response to item 1.a:
The standard piping and special RCP LOCA hydraulic suppres-sors are selected to allow necessary thermal growth rates and to restrain motions in excess of thermal growth rates.
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MIDLAND PLANT 4
Response to IE Bulletin 7%C5
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June 10, 1975 l
The hydraulic suppressors parmit essentially unrestrained thermal growth rates up to a marimum of 20 inches per minute.
Once the displacement velocity of 20 inches per minute for standard piping suppressors is exceeded, the hydraulic suppressors actuate (lock). A provision is built into a standard piping system suppressor to allow continued thermal expansion capability.
l The anticipated dynamic velocities for which snubber
. actuation is required vill be sufficiently higher than, for an avample, the 20-inch I er minute set point for standard piping anubbers to ensure that snubber actuation (locking) due to the anticipated dynamic event occurs.
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-Once the actual load that the snubber must restrain is g
calculated a check is made to determine if a suppressor is available in that size..If no standard size snubber is available at the calculated load the next largest standard size snubber is specified.
g Thus the design margins between the calculated load and the specified rated load varies. For the special design RCP LOCA snubbers the specified size is an average of 5% to 10% larger than the calculated load. An additional safety margin between the specified rated load and the actual. load capability of the snubber is incorporatect into the snubber design by the manufacturer. This safety margin varies with the snubber and is not known at this time.
Each hydraulic suppressor detail drawing vill list the -
following data:
i a) Valve locking velocity, inch / min b) 31eed rate, inch / min l
c) Design load and stroke d) Hot and cold settings i
, Response to item 1.b :
The test procedure of our expected supplier of standard i
suppressors is described below.
j l.
All suppressor valve parts are visually inspected for cleanliness and completed deburring. Parts are manually cleaned and deburred as necessary.
i 2.
After assembly, the valve is placed in a flow testing facility.
The valve assembly actuation and bleed rate set points are made and documented.
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J. G. Keppler 3
g MIDLAND plt 3T Response to IE Bulletin 75-05 June 10, 1975 3.
After complete assembly, each hydraulic shock and sway suppressor is mounted in a " Fill and Test" facility. During the fill and purge of the unit, verification that the $2 nit rod is free to move through its full stroke is made. Verification is then made that the suppressor vill actuate and that it is fully purged of air.
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The test procedures for the special RCP IDCA snubbers have not yet been received from the vendor; therefore we cannot provide l
detailed information at this time. We have, however, specified the j
following tests:
i' i) In the first test a constant load equal to 1/25 of mav4=n capacity shall be applied. Movement shall not be less than 1.5 inches in one hour.
ii) In the second test, the maximum capacity load shall be applied.
Movement shall not be more than 0.10 inch in one minute.
1 Response to item 1.c:
Visual inspection for hydraulic -fluid leakage vill be performed during extended plant outages. An air purge and lock-up velocity check vill be made following repairs or maintenance to the snubber fluid system.
hoursverytruly, i
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SHH/RCB/je CC: Assistant Director for Construction and Operations, Office of Inspection & Enforcement, USNRC Washington, DC 20555 I
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For infirmation.
Nots and retyrn.
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.iaturs TO (Name and unst) unHALS ALMARKS Consumers Power Company IE Chief, FS&EB IE:HQ(4)
Midland Plant Units 1 and 2 D^"
Licensing (4)
DR Central Files 750 3-and 50-330
.T o4 an. OMTDC TQ (Name and unst) tM3TIALS Af.MAAK5 U
A/D for Info, Processing Region I Region II D^"
PDE Tnen1 MR TO (Name and unet) paTIALS REAeAAKS NSIC TIC OGC, Beth, P-506A D^n R. Callen
.J. Murrav. GC (2)
FROM (Narne and unst) ngMAAKs Dr. W. E. North Attached is a copy of licensee's adeqaute reply dated j
M. M. Cherry FROM:
June 10, 1975, to IE Bulletin 75-05.
D. M. Hunnicutt IE:III 1
PHONE MS DATE 06-26-75 use ornca soc ron acomonat n Aans om, im o. us..
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