ML19261A587
| ML19261A587 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 01/26/1979 |
| From: | Counsil W NORTHEAST UTILITIES |
| To: | Ziemann D Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML19261A588 | List: |
| References | |
| TASK-05-04, TASK-5-4, TASK-RR NUDOCS 7902050079 | |
| Download: ML19261A587 (4) | |
Text
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MOltTHI!R!iT IITII.ITII!!i PO Box 270 HARTFOAD. CONNECTICUT 06101 (203) f66-6911 c
k L
J January 26, 1979 Locket No. 50-245 Director of Nuclear Reactor Regulation Attn:
Mr. D. L. Ziemann, Chief Operating Reactors Branch #2 U. S. Nuclear Regulatory Commission Washington, D. C.
20555
References:
(1)
G. Lear letter to D. C. Switzer dated August 11, 1977 transmitting NUREG-0312, " Interim Technical Repor t on BWR Feedwater and Control Rod Drive Return Line Nozzle Cracking".
(2)
D. L. Ziemann letter to D. C. Switzer dated March 10, 1978 entitled, " Millstone Nuclear Power Station, Unit No.1 Feedwater and Control Rod Drive Return Nozzle Monitoring Program".
(3)
D. C. Switzer letter to G. Lear dated November 18, 1977 entitled, ' Millstone Nuclear Power Station, Unit No. 1 Feedwater and Control Rod Drive Nozzle Monitoring Program".
(4)
D. C. Switzer letter to D. J. Skovholt, dated December 19, 1972.
Gentlemen:
Millstone Nuclear Power Station, Unit No.1 Feedwater and Control Rod Drive Nozzle Monitoring Program As required by References (1) and (2), we are providing herein a detailed descrip-inspec tion program f or monitoring the F( edwater and Control Rod tion of c
Drive Return Nozzles f or 1979 and 1980.
During the last refueling outage, (Spring,1978), all four feedwater nozzler, were ultrasonically examined (UT) from the vessel exterior. At that time, the examinations of all the feedwater nozzle blend radii and bore regions showed no reportable indications. A summary of the recordable indications that were f ound and their dispe loions is piovided in Attachment 1.
As discussel in our presentation to the NRC Staf f on January 11, 197 9 ano summarized in Attach-ment 2, PT examinations will not be performed but ultrasonic examinations cf all four (4) feedwater nozzles will be performed by the General Electric Company during the Spring, 1979 refueling outage.
These examinations will be performed using the same techniques as described in Ref erence (3).
The acceptance criteria to be utilized will be as defined in Attachment 3.
If reportable UT indications are discovered, the procedure outlined in Paragraph 1 of Section 6.3 of NUREG-0312 will be followed.
790205 oo7g
During the Spring, 1978 refueling outage, the CRD return line was rerouted to the feedwater line outside the primary containment. An analysis of the CRD return nozzle has been performed as described in Reference (3) which illustrates that the elimination of significant thermal stresses from the nozzle region caused by this reroute results in levels of stress intensity f actor for sub-stantial postulated flaw depths far less than the available nozzle material fracture toughness. Present plans include removal of the thermal sleeve, capping of the nozzle, and in-vessel PT examinations during the 1980 outage.
These activities are scheduled to be perf ormed in conjunction with the feed-water nozzle clad removal which is now planned for the Fall, 1980 refueling outage. Combination of these tasks will result in substantially reduced personnel exposure and the most judicious use of critical path outage time.
An ultrasonic examination of the CRD return nozzle blend radius area will be conducted to verify the absence of such defects during the Spring,1979 outage. If reportable indications are detected, the CRD thermal sleeve will be removed and the nozzle blend radiu.= examined using liquid penetrant.
Personnel performing all ultrasonic examinations shall be adequately trained in the use of the techniques such that minimum stay times will be ensured.
During our presentation to the NRC Staff on January 11, 1979, we were also requested to enclose a summary description of any water chemistry problems that may have occurred during the last two years, in the primary coolant system.
The only such water chemistry problem that has occurred at Millstone Unit No. I was a result of the Chloride Intrusion Incident of September 1,1972. A detailed report of this event was submitted in Reference (4). No water chemis-try problems have occurred in the last two years, and the coolant chemistry has remained within the Technical Specification limits.
If you have any questions with our feedwater and CRD nozzle monitoring program, please contact us.
Very truly yours, NORTHEAST NUCLEAR ENERGY COMPAhT
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W. G. Cou'nsil Vice President Attachment
ATTACINENT 1 FEEDWATER N0ZZLE SibDiARY RECORDABLE INDICATIONS ZCNE 2 Angle Amp Nozzle Ref.
% FSH Disposition N4B 255*
50%
Does not travel in time position. Rough surface.
N4C 105*
100%
Does not travel in time position. Rough sur face.
Can be seen in one direction only.
75*
90%
Does not travel in time positim. Rough surface.
Indication considered too high on inspection zone.
255" 90%
Does not travel in time position. nough surface. Ca i be seen in one direction only.
195" 95%
Does not travel in time position. Can be seen in one direction only.
N4A 343 100%
Does not travel in time position.
Indications not in inspection zone.
ZONE 3 W
Inches CW Amp
- Nozzle, Ref.
From W Ref.
% FSH Scan Disposition NI L 180 3.875" 35%
CCW Indication not at same location when scanned in opposite direction.
NEU-01-003 86.701.0011 ATTACHMEliT 2 FATIGUE EVALUATION OF EXISTING FEEDWATER N0ZZLE/SPARGER DESIGN MILLSTONE NUCLEAR POWER STATION UNIT 1 Prepared for:
Northeast Utilities Service Company Prepared by:
Nuclear Technology, Incorporated Prepared by:
Issued by:
W S hWF S.
S. Tang 8
N7 W. Edwards,((E.
Checked and A roved by g//
/A Date:
January 19, 1979 P. C. Ricc[rdella, P.E.
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