ML20245H879
| ML20245H879 | |
| Person / Time | |
|---|---|
| Site: | Mcguire |
| Issue date: | 08/08/1989 |
| From: | Tucker H DUKE POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| IEB-88-008, IEB-88-8, NUDOCS 8908170330 | |
| Download: ML20245H879 (2) | |
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. DUKE POWER GOMPANY t
P.oi Box 33189 -
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CHARLOTTE, N.O. 28242 t
HALB. TUCKER TELEPHONE vion Psamanewr
.(704) 073-4531-T NLMILEAm PmODtMMPON
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' August'8,L1989.
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Document' Control Desk
.U. S.> Nuclear Regulatory. Commission Washington,<D. C..20555
' Subjecti McGuire Nuclear Station, Unit 2 Docket No. 50-370 NRC.Bulletin 88-08 Thermal Stress in Piping Connected to The Reactor Coolant System Gentlemen:
22, 1988, the NRC issued Bulletin 88-08,' Thermal Stresses in Piping On' June
' Connected to the Reactor Coolant System. NRC Bulletin 88-08 requires the inspection of unisolable sections of. piping connected to the Reactor Coolant
' System which may be subjected to excessive thermal stresses. My September 9,
'1988 letter to the Document Control Desk conservatively identified 1-1/2 inch diameter safety' injection piping for inspection, This piping is not as likely
- to be subjected to. thermal stresses as Farley's 6 inch diameter piping because
. thermal stratification may not occur as readily in small diameter' piping.s The'McGuire Unit 2 safety injection piping is now being inspected during the.
end of cycle 5 refueling outage. While inspecting safety injection piping going into cold' leg
'D', it was determined that two elbows cannot be accessed whithout removal'of pipe rupture restraints. The rupture restraints consist of 6 inch Schedule 160 guard pipe' surrounding ~the process' pipe. The guard pipe is
- supported by multiple tube steel members.'To access the process pipo'for inspection, it would be necessary to cut and' weld back.together each'of these members-'and the 6 inch guard pipe. These are Quality Assurance Condition 1 pipe restraints which would require hold points for weld inspection during reassembly. The weight of the components would require the use of hoists to
. support the components during removal and restoration.
An estimate of 300 man-hours has been calculated for this job. The work area is confined and within approximately five feet of the Reactor Coolant System Gold Leg. The-general radiation field in the' area is approximately 90 mR/hr.
- The dose estimate for this~ job ~ is : 20-25 man-Rem.
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- Therefore, due to ALARA considerations I am requesting a partial exception from the requirements of'NRC Bulletin 88-08 for the two elbows in the McGuire Unit.2 'D' cold leg 1-1/2' inch diameter safety injection piping. The remainder of this line will:be inspected to the extent practical with the rupture-
- restraints _in' place. 1-1/2 inch safety injection piping going into the other three cold legs is also being inspected. It should be noted that similar 1-1/2 inch diameter piping has been inspected by ultrasonic volumetric examination l
at McGuire Unit I and Catawba Units 1 and 2. These inspections revealed no findings which could have indicated the presence of excessive thermal stress.
'fEdo 8908170330 890808 W DR' ADOCK 05000370i i
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Document Control Desk August 8, 1989 Page 2 Additionally, temporary instrumentation is being placed in this line to monitor thermal conditions of the pipe and verify that 1-1/2 inch diameter safety injection piping is not subjected to excessive thermal stresses.
Since McGuire Unit 2 is scheduled to return to power operation following I
completion of the end of cycle 5 refueling outage, it is requested that the NRC review and approve this partial exception from the requirements of Bulletin 88-08 prior to August 28, 1989.
Very.truly yours, B. [ ',
$L Hal B. Tucker JGT/4/MNS88-08 xc:
Mr. S. D. Ebneter Regional Administrator, Region II U. S. Nuclear Regulatory Commission 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323 Mr. P. K. Van Doorn NRC Resident Inspector McGuire Nuclear Station l
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