ML20040A901

Feedwater Nozzle & Sparger Inservice insp,1981 Refueling Outage

ML20040A901
Person / Time
Site:	Nine Mile Point
Issue date:	12/29/1981
From:	NIAGARA MOHAWK POWER CORP.
To:
Shared Package
ML20040A899	List: ML20040A898 ML20040A901
References
RTR-NUREG-0619, RTR-NUREG-619 NUDOCS 8201220286
Download: ML20040A901 (44)

Text

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NI AGARA MOIIAWK POWER CORPORATION NINE MILE POINT UNIT 1 PEEDWATER NOZZLE AND SPARGER INSERVICE INSPECTION 1981 REFUELING OUTAGE December 29, 1981 8201220286 820104 PDR ADOCK 05000220 G PDR '

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TABT.E OF CONTENTS I. U;2RODUCTION A. Purpose B. Background II.

SUMMARY

III. DISCUSSION A. Feedwater Nozzle Examinations B. Feedwater Sparger Examinations IV. REFERENCES V. APPENDICES A. NES and GE UT Inspection Procedures i

'I. INTRODUCTION A. Purpose This report discusses the results of inservice inspec-

}

tions of the Nine Mile Point Unit 1 feedwater nozzles and spargers that were performed during the 1981 refuel-Ing outage. The refueling outage began on March 6, 1981 and was completed on July 2, 1981. The information included in and the content of this report are in accordance with the reporting requirements of Section t

4.4.3 of NUREG-0619, BWR Feedwater Nozzle and Control Rod Drive Return Line Nozzle Cracking (November 1980).

B. Background Nine Mile Point Unit 1 began operation in November 1969 i

and at the time of the 1981 refueling outage had been in service for about 11 years. During the 1977 refueling outage, liquid penetrant (PT) examinations of the feed- ,

water nozzles revealed the existence of cracks similar to the nozzle cracks observed in other oper.ating BWRs.

Niagara Mohawk has since completed extensive feedwater ,

nozzle examinations, repairs, and system changes which are expected to eliminate further cracking of the r nozzles. A summary of these efforts, performed prior to the 1981 refueling outage, is given below.

During the 1977 refueling outage, Niagara Mohawk removed I-l

i i the originally installed loose-fit feedwater spargers which at that time had been in service for about 7 years. One nozzle, the southeast, was selected for PT examination. A 100 percent PT examination of the blend radius and nozzle bore of this nozzle revealed the existance of approximately 25 cracks., Stainless steel cladding and about 0.25 inches of base metal were then removed from all four nozzles using portable boring equipment designed by Combustion Engineering. The surfaces of all four nozzles were then examined by PT.

Results of these PT examinations, after clad removal, revealed five cracks in the southeast (SE) nozzle and one crack in the southwest (SW) nozzle. No defect indications were found in either the northeast (NE) or

northwest (NW) nozzles. The cracks in the SE and SW nozzles were removed by progressive grinding and PT examination until all linear indications were removed.

Grindout cavities were subsequently blended to reduce stress concentrations. The approximate location and dimensions of the final grindout cavities are summarized i

in Table I-1.

t New feedwater spargers of an improved design were installed to replace the original loose-fit spargers.

The main features of the replacement feedwater sparger design were:

I-2 4

.- - r,~ .

i *.

l A single piston ring seal assembly was provided at the end of the thermal sleeve to minimize the i bypass leakage of feedwater between the thermal sleeve and the feedwater nozzle bore.

Double flow baffles, with leakoffs, which cover the

. nozzle opening were provided to prevent mixing and thermal cycling of the relatively cold bypass

feedwater leakage with the hot reactor coolant at 3

the blend radius region of the nozzle.

Basic sparger materials were changed from as-welded 4 austenitic stainless steel to carbon steel and Inconel for better resistance to stress corrosion cracking.

A slight elliptical interference fit (0.050") was provided at the end of the thermal sleeve and the replacement sparger was installed with a signifi-cantly greater preload than the original loose-fit sparger to improve its resistance to flow induced vibration.

The four feedwater nozzles were ultrasonically (UT) examined from the outside of the vessel using procedures and equip-ment developed by General Electric (GE) . This UT examina-tion established a baseline for subsequent nozzle examinations.

I-3 r t

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During the 1979 refueling outage, an in-service UT examin-ation of the four feedwater nozzles was performed by GE. No change from the baseline examination was observed. In addi-tion, the Reactor Water Cleanup (RWCU) return line was rerouted to the feedwater line in accordance with Section 4.2 of NUREG-0619.

During the 1981 refueling outage, an in-service UT examina-tion of the four feedwater nozzles was performed by Nuclear Engineering Services (NES) and also by GE. An apparent change from the baseline examination was observed. The results of these and subsequent examinations that were performed to resolve the apparent change from the baseline examination are discussed in detail in the following sections of thi3 report.

The number of startup/ shutdown cycles for the Nine Mile Point Unit 1 reactor vessel from the beginning of operation in 1969 to the 1981 refueling outage is given in Table I-2.

l l

I-4

s TABLE I-l GRINDOUT CAVITIES IS NMP-1 FW NOZZLES NOZZLE APPROXIMATE CAVITY LOCATION ORIENTATION1! SIZE SW l BORE 7 O' CLOCK 1.18" X 10.12" SE 1 BORE 1 O' CLOCK 1.47" X 10.62" 2 BORE 7 O' CLOCK 0.38" X 5.25" 3 BORE 8 O' CLOCK 0.25" X 3.75" 4 BORE 10 O' CLOCK NOTE 3 NOTES:

1. Viewed from the center of the reactor vessel and facing the nozzle.

2. Two cracks were blended'into one cavity.

3. Cavity depth after grinding was too shallow to measure.

l

, s.

TABLE I-2 NUMBER OP JIARTUP/ SHUTDOWN CYCLES AT NINE MILE POINT UNIT 1 PERIOD , NUMBER OF CYCLES l DURING PERIOD CUMULATIVE 1969 Initial Startup -

95 95 1977 Refueling Outage '

1977 Refueling Outage - 13 108 ,

1979 Refueling Outage 1979 Refueling Outage - 17 125 1981 Refueling Outage 1981 Refueling Outage - 2 127 Present

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II.

SUMMARY

i This section of the report presents a summary of the inservice inspections of the feedwater nozzles and spargers that were performed during the 1981 refueling outage.

1. All four feedwater nozzles were ultrasonically (UT) examined by Nuclear Energy Services, Inc. (NES) using i

i procedures and equipment that were different from those used by GE for the 1977 baseline and 1979 inservice inspections. The NES inspections revealed one relevant indication in the SE nozzle. The UT indication was determined to be located in the existing grindout cavity at the 1 o' clock position of the nozzle.

2. GE was contracted to perform an independent ultrasonic examination of the SE nozzle using the same procedures and equipment used by GE for the 1977 baseline and 1979 inservice inspections. The GE inspections confirmed the presence of the UT indication detected first by NES during their inspections of the nozzle.

3. The individual characteristics of the NES and GE ultrasonic examination procedures and equipment are i

described in Appendix A. The main difference between the NES and GE procedures, when examining the region of the nozzle containing the UT indication, is shown in f

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,- -. ., - - - ~ . -.,

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l Figure II-1. The NES transducer transmits a single

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shear wave beam (i.e. acoustic signs 1) at a compound angle such that the beam has vector components in both the circumferential and longitudinal directions of the nozzle, whereas, the GE transducer transmits the beam in only the circumferential direction of the nozzle. As shown in Figure II-1, in order to pick up the UT indica-tion with the GE procedure, the transducer had to be located at the very edge of the inspection zone (i.e. up against the OD blend radius between the barrel of the nozzle and the reactor vessel shell). With the NES procedure, the transducer could be located approximately in the middle of the inspection zone. Thus, the UT indication is more readily detected using the NES procedure.

4. Based on the results of the NES and GE UT examinations,

the decision was made to remove the SE feedwater sparger and perform a 100 percent liquid penetrant examination of the nozzle bore and face in accordance with NUREG-1 i

0619. The initial PT examination of the nozzle showed no indications in the existing grind-out cavity at the l

1 o' clock position where the UT indication was believed

! to be located. The initial PT examination did reveal five small reportable indications, three in the. bore and two in the face. These indications were less than 0.25" in length and were removed by flapper wheel and light II-2

grinding.

The amount of metal removed was less than 0.020". Subsequent PT examinations confirmed their removal.

These PT indications were considered to be minor non-relevant surface irregularities and not new fatigue cracks in the nozzle.

5. The following additional inspections were performed to confirm the PT examination results.

a. The grindout cavity located at the 1 o' clock position was examined by magnetic particle (MT) and eddy current (ET) methocp. Results of these examinations were negatile, i.e. no indications in the grindout cavity were observed. These inspec-tions were performed at the recommendation of GE personnel who stated that tests performed by GE on a mock-up nozzle with known thermal fatigue cracks indicated that the MT and ET examination methods are more sensitive in detecting tight surface flaws than PT. .

b. Finger damping tests were performed to determine if the amplitude of the reflected wave could be damped by placing a finger on the nozzle at the point where the acoustic signal intersects the inside surface of the nozzle as shown in Figure II-2.

Finger damping was performed by Niagara Mohawk, GE, and NES personnel in the vessel while NES performed II-3 I

. ~.

a UT examination from the outside of the vessel.

The UT signal was damped by about 20 percent by the finger damping technique. At the point where the signal was damped, the Niagara Mohawk inspector reported that he could feel a definite surface discontinuicy or " shoulder" in the grindout area.

6. Based on the results of the PT, MT and ET examinations and the finger damping tests, it was concluded by Niagara Mohawk that the UT indication was the result of a geometric reflector and not a crack in the nozzle.

7. A new feedwater sparger was installed in the SE nozzle.

The design of the new sparger is the same as the replacement spargers installed during the 1977 refueling ,

outage. In-vessel visual examinations of the three ,

remaining installed spargers and out-of-vessel visual examinations of the removed sparger after decontamination indicated that the performance of the replacement feedwater spargers since their installation in 1977 has been satisfactory. Specifically,

a. PT examination of the SE nozzle after about 4 years of operation indicated that the replacement sparger was effective in eliminating the initiation of thermal fatigue cracks like those observed in 1977 after about 7 years of operation.

II-4

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i b.

There was no evidence of fretting or pitting j

corrosion at the piston ring seal diameter or J

i contact diameter of the flow baffles.

c.

1 There was no evidence of flow-induced vibration of

] the sparger. The spargers were in a like-new

condition.

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2 OD BLEND RADIUS StELL 1

NES GE j sN ,

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NOZZLE 5

BARREL L APPROXIMATE LOCATION OF UT INDICATION 1

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i GRINDOUT CAVITY AT ONE O' CLOCK l

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LOCATI0li 0F t1ES N1D GE TRNiSDUCERS l

TO PICK UP UT If1DICATI0ft Ifi SE fl0ZZLE l

FIGURE 11-1

f NES PIFLECTED, WAVE.

TRANSMITTED WAVE *

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A PORTION OF THE TRANSMITTED WAVE IS ABSORBED BY THE " THUMB" WHICH DECREASES THE MAGNITUDE OF THE REFLECTED WAVE E FW NOZZLE - -

FINGER DAMPING TEST-0F UT INDICATION IN SE N0ZZLE FIGURE II-2

III. DISCUSSION This section of the report discusses the results of in-service inspections of the feedwater nozzle and spargers that were performed during the 1981 refueling outage at Nine Mile Point Unit 1.

A. Feedwater Nozzle Examinations During the 1981 refueling outage ultrasonic examinations were performed on the four feedwater nozzles by Nuclear Energy Services, Inc. (NES). The inspection procedure and equipment used by NES was different from that used by GE for the 1977 baseline and 1979 inservice inspec-tions. A brief description of the NES and GE procedures is given in Appendix A. Results of the NES inservice inspections of the feedwater nozzles are summarized below.

Northwest Nozzle -- Ultrasonic examination, from the I

nozzle barrel, revealed no indications in the counterclockwise (CCW) scan and one indication in the clockwise (CW) scan. This indication was interpreted by NES to be of geometric nature due to its characteristic behavior. The signal showed no

" walking" movement and could only be obtained from I

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2 .

one direction. The signal amplitude was between 20%

to 25% of DAC (distance amplitude correction) .

Northeast Nozzle -- Ultrasonic examination, from the nozzle barrel, revealed no indications in the CCW scan and one indication in the CW scan. This indication was also interpreted by NES to be of geometric nature due to its characteristic behavior. The signal showed no " walking" movement and could only be obtained from one direction. The signal amplitude of this indication was between 20%

to 25% of DAC.

Southwest Nozzle -- Ultrasonic, examination, from the barrel side, revealed one indication in the CCW scan and one indication in the CW scan. Both indications upon re-examination were interpreted by NES to be geometric. Neither signal showed " walking" and 5 could only be obtained from one direction. Signal amplitude from indication number 1 was 55% of DAC and 20% to 25% of DAC for indication number 2. The

, amplitude of indication number 1 may have been caused by rough surface conditions and could not be obtained during re-examination. The re-examination amplitude was 15% to 20% of DAC.

Southeast Nozzle -- Ultrasonic examination, from the barrel side, revealed numerous indications around III-2 i

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the 0' datum point area. Upon evaluation it was determined that the numerous indications were in fact one relevant indication. The indication was determined to be approximately located in the existing grindout cavity at the 1 o' clock position (see Table I-1), of the nozzle as shown in Figure III-1. Other angles including 0', 30*, and 45*

straight and angle beams were also used to verify

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the indication. s.

Niagara Mohawk then contracted.with GE to perform an independent examination of the SE nozzle using the same l

procedures and equipment used for the 1977 baseline and 1979 inservice inspections.

The main difference between the NES and GE ultrasonic examination procedures, when examining the region of the nozzle containing the UT indication, is shown in Figure III-2. The NES transducer transmits a single shear wave beam (i . e . acoustic signal) at a compound angle such that the beam has vector components in both the circum-ferential and longitudinal directions of the nozzle, whereas, the GE transducer transmits the beam in only i

the circumferential direction of the nozzle. As shown in Figure III-2, in order to pick up the UT indication with the GE procedure, the transducer had to be located at the very edge of the inspection zone (i.e. up against III-3

-_-___-__-_~

9 the OD blend radius between the barrel of the nozzle and the reactor vessel shell). In fact, the GE examiner reported that it was even necessary to " cock" the trans-ducer about 3' in order to get the maximum amplitude.

With the NES procedure, the transducer could be located well within the limits of the inspection zone and still pick up the UT indication. Thus, the UT indication was more readily detected by the NES procedure.

The SW feedwater nozzle, where NES had reported two geometric reflectors, was also ultrasonically examined by GE. Using the GE procedures and equipment, only normal UT responses from the nozzle bore were observed.

The two geometric UT indications reported by NES were not detected with the GE procedures.

Based on the results of the UT examinations of the SE nozzle by NES and GE, the decision was made by Niagara Mohawk to remove the southeast feedwater sparger and perform a 100 percent liquid penetrant examination of the nozzle in accordance with the requirements of Section 4.3.2.3 of NUREG-0619. GE personnel performed l all in vessel examinations except the finger damping evaluation which was performed by Niagara Mohawk, NES, and GE.

C On April 19, 1981, the SE feedwater sparger was removed and on April 20, 1981 the nozzle bore and face were III-4 ,

t 9 5

cleaned for liquid penetrant examination. On April 21, 1981, an initial PT examination of the nozzle bore and face was performed.

Results of this initial PT examination showed no indications in the existing grindout cavity at the 1 o' clock position where the UT indication was believed to be located. The initial PT examination did result in five small reportable indications; two on the nozzle face and three in the bore of the nozzle as described below. The specific locations of these indications are shown in Figures III-3 and III-4.

Indication Description '

1 0.25" linear on nozzle face at 270' 2 0.25" linear on nozzle face at 280' 3 0.12" linear in nozzle bore at 260*

4 A cluster of five 0.060"-0.12" rounded indications in nozzle bore at 290*

5 0.12" linear in nozzle bore at 275' The indications revealed by the initial PT examination were removed by flapper wheel and light grinding. The

maximum depth of metal removed by the flapping and grinding operations was less than 0.020". Subsequent PT )

, examinations of the nozzle bore on April 21, 1981 and III-5

. .F .

the nozzle face on' April 22, 1981 confirmed their complete removal. Since these indications were removed with no significant metal loss, it was concluded that these indications were minor non-relevant surface irregularities, and not new thermal fatigue cracks in the nozzle.

Also on April 22, 1981, a PT examination was performed on the reactor vessel end brackets for the SE teedvater sparger. No reportable indications were observed.

On April 22, 1981, a magnetic particle (MT) examination of the grindcut cavity was performed by CE using a DC magnetic yoke with dry magnetic particles. Results of 4

the MT examinaticq were negative, i.e., no recordable indications were observed in the grindout cavity. On April 23, 1981, an eddy current (ET) examination of the grindout cavity was attempted. The examination proved inconclusive because of excessive surface roughness.

During the evening of April 23, 1981, the grindout cavity was conditioned with a flapper wheel. On the morning of April 24, 1981, a successful ET examination was performed by GE. The grindout-cavity area was 4

scanned three times in its entirety with no recordable indications.

The MT and ET examinations of the grindout cavity were performed by GE who stated that tests performed by GE on III-6 i

a mockup nozzle with known theraul fatigue cracks indicated that the MT and ET methods were more sensitive to tight surface cracks than PT. In addition, the MT and ET methods also have the capability of locating near-surface flaws. \

On April 23 and 24 1981, finger damping of the UT

indication was successfully performed from inside the 4

1 vessel. NES personnel performed a UT examination from

)

1 -

.outside of the vessel while Niagara Mohawk, NES and GE i

personnel inside the vessel were able to damp the ampli-1 l

tude of the reflected wave by placing a finger on the nozzle at the point where the acoustic signal intersects j the nozzle surface as shown in Figure III-5. Communi-i cation was established between the incide and outside of the vessel using headphones. The UT signal was damped by about 20 percent by the finger damping technique. At the point where the signal was damped, the Niagara i

Mohawk examiner reported that he could feel a definite 2

surface discontinuity, or " shoulder" in the grindout J

area.

Based on the results of the in-vessel surface PT, MT, i

and ET examinations, and the finger damping tests, 3 Niagara Mohawk concluded that the UT indication in the

, SE nozzle reported by the NES and GE inspections was the result of a geometric reficctor and not a crack. It was III-7 i

9 further concluded that the UT indication was not observed during the 1977 baseline and 1979 inservice examinations by GE due to its unique location and the specific techniques of the GE examination procedures.

, Using the GE procedure, the indication had unequal ultrasonic reflections from the clockwise and counter-clockwise examining directions. In order to obtain 1

maximum amplitude from the reflector in both examining directions, it was necessary to cock the transducer approximately 3 . Thus, it is not unreasonable to conclude that the UT indication was simply missed during the 1977 baseline and 1979 innervice inspections by GE.

On April 24, 1981, a second 100 percent PT examination of the nozzle bore a.nd face was performed. Three rounded indications were reported in the nozzle face at 85' as shown in Figure III-6. The three indications were removed by flapper wheel and light grinding. The depth of metal removed was less than 0.020". A final PT was then performed on April 24, 1981 with no reportable l indications. It was concluded that these indications were also the result of surface irregularities because i

3 the indications did not show up on previous PT's and were removed with no significant metal loss.

A summary of all nondestructive exminations performed on

the feedwater nozzle during the 1981 refueling outage is i given in Table III-1.

III-8 i

On April 28, 1981, a new feedwater sparger was installed in the SE nozzle. The new sparger is of the same design as the replacement spargers installed in 1977.

B. Feedwater Sparger Exa.tinations In-vessel visual examinations were performed on the NE, NW and SW feedwater spargers, which were not removed.

Results of these in-vessel examinations are provided below.

l

1. Flow Baffles -- All outer flow baffles were determined to be preloaded against the machined conical surface of the feedwater nozzle. There was no evidence of fretting or pitting corrosion on the nozzle face at the flow baffle contact dinmeter.

2. Vibration -- There was no evidence of flow-induced vibration at the sparger end brackets or end bracket pins. A 0.125" x 0.75" crack was noticed on one end bracket pin of the NE sparger in the nonstructural weld between the pin and pin handle as shown in Figure III-7. It is believed that the weld was cracked during installation of -the sparger in 1977 by hitting the pin with a sledge hammer since the pin handle was noticed to be slightly distorted.

The crack in the weld was repair welded at the time III-9

the end bracket pin retainers were welded on the new SE sparger.

3. Flow Holes -- No flow hole cracks were observed.

4. Bearing Pads -- During their installation, the spargers were preloaded against the reactor vessel wall. It was determined from the in-vessel visual examinations that the bearing pads on the sparger arms were no longer in contact with the reactor vessel wall as shown in Figure III-8. Shim plates were used to estimate the gap. The minimum gap, which provides an indication of how much relaxation

may have occurred inservice is given below for the three installed spargers.

Sparger Min. Gap At Bearing Pad NE 0.100" -

NW 0.040" SW 0.015" At installation, the flow baffles were installed with an initial interference of 0.170". Thus, the remaining interference on the NE flow baffles is 0.070". This correspondense to a remaining preload

, of about 2850 lb g , which exceeds the calculated applied hydraulic load of about 1380 lb g. On this basis, the condition of bearing pads on the NE, NW i

f III-10 l

I

9 and SW spargers is considered acceptable for continued operation.

On June 4, 1981, the removed SE feedwater sparger was visually examined after decontamination by an electrolytic proccss. Except for discoloration, the sparger was determined to be in a like-new condi-tion. There were no cracks at'the flow holes, no signs of erosion / corrosion on the flow shroud contact edge, and no pitting in the thermal sleeve.

This visual examination further confirmed the satisfactory performance of the replacement feedwater spargers installed in 1977.

1 1

i III-11

m TABLE III-l SEQUENCE OF PEEDWATER NOZZLE EXAMINATION - 1981 REFUELING OUTAGE AREA DATE EXAMINATION EXAMINER EXAMINED RESULTS 3/14/81 UT NES NE No relevant indications.

NOZZLE 3/14/81 UT NES NW No relevant indications.

NOZZLE 3/14/81 UT NES SE One relevant indication NOZZLE reported at 5* clockwise from zenith looking toward the center of the vessel.

3/14/81 UT NES SW No relevant indications.

NOZZLE 3/21/81 UT GE SE One relevant indication NOZZLE reported in deep grind out area on the nozzle ID (clockwise looking toward the center of the vessel).

4/21/81 UT GE SW No relevant indications, and NOZZLE 4/22/81 ,

4/21/81 PT GE SE NOZZLE Five indications reported; BORE AND 3 in nozzle bore and 2 on FACE nozzle face. None in grindout cavity.

4/21/81 PT GE SE NOZZLE No indications.

BORE 4/21/81 PT GE END No indications.

BRACKETS 4/22/81 PT GE SE NOZZLE No indications.

FACE ,

r

TABLE III-l (Continued)

AREA DATE EXAMINATION EXAMINER EXAMINED RESULTS i

4/22/81 MT GE SE NOZZLE No indications.

j. GRINDOUT AREA 4/23- UT GE/NES/ SE NOZZLE Finger damping of indication i

24/81 NIAGARA performed by Niagara Mohawk /

MOHAWK NES and GE personnel in the vessel while NES personnel performed a UT examination from outside of the vessel.

Signal was damped about 20

, percent.

4/24/81 ET GE SE NOZZLE No indications (grindout

GRINDOUT cavity was flapped smooth AREA prior to successful ET).

4/24/81 PT GE SE NOZZLE Three indications reported j BORE AND on nozzle face.

FACE

., 4/24/81 PT GE SE NOZZLE No indications.

BORE AND FACE i

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OD 11 LEND RADIUS VESSEL S!! ELL l

j NOZZLE BARREL l

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APPROXIMATE LOCATION OF UT INDICATION ,

} Q TW NOZZLE SECTION A-A A

I F APPROXIMATE LOCATION OP UT INDICATION

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. I GRINDOUT CAVITY AT ONE O' CLOCK T

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l APPR0XII1 ATE i LOCAT10ft 0F UT lilDICAT10!1 Ifl SE Fil fl0ZZLE

! FIGURE 111-1 .

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OD DLEND RADIUS VESSEL SilELL NES GE i f

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d BARREL APPROXIMATE LOCATION OF UT INDICATION Q FW NOZZLE SECTION A-A y l -

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J GRINDOUT CAVITY

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. LOCATION OF NES AND GE TRAf1SDUCERS TO PICK UP UT INDICATION IN SE N0ZZLE FIGURE Ill-2

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0*

330* 30*

300*

60*

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270* 3.5": , -

90* - -

2 NOZZLE ID, 240* 11,1= 120*

4 210* 150'

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180*

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, LOCATION OF PT INDICAT10flS l - SE N0ZZLE FACE (IfilTIAL 100% PT)

FIGURE 111-3

. . . , . ., . . . . - . . _ . , . . . . . _ ,, . - - . . . . ~ - . , _ _ . , _ . - _ . ._

O' 330 -

30' 4.5" int N nozzle bore 0* 60*

4 9.5" into nozzle bore 270*- - ~

@ l 1" into nozzle bore '

240* l 120' 150 210* NOZZLE ID 7 ,,

180' LOCATION OF PT lilDICATIONS

- SE N0ZZLE BORE (INITIAL 100% PT)

FIGURE 111 11

I NES REFLECTED TRANSMITTED WAVE i

A PORTION OF THE TRANSMITTED WAVE IS ABSCRBED BY THE " THUMB" WHICH DECREASES THE MAGNITUDE OF THE REFLECTED WAVE Q FW NOZZLE. _ _ _

FINGER DAf5PIfiG TEST OF UT IfiDICATION Ifl SE fl0ZZLE FIGURE III-5 -

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1 0*

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l 300* 60*

270s _

3.25"-@- h9 0. _ _

NOZZLE ID

, 11.1" 240 120*

1 J 210 150-180*

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! LOCAT10fl 0F PT INDICATIONS-SE fl0ZZLE FACE (SECOND 100% PT)

FIGURE 111-6

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PIN HANDLE BENT DURING INSTALLATION L i

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\t i Ut l g f LOCATION OF CRACK 6

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j / IN WELD OF END LOCATION OF CRACK

/ BRACKET PIN I IN WELD OF END i

1- A BRACKET PIN

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l j CRACK IN WELD OF END BRACKET PIN FIGURE III-7 p

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II t' Ti!EIWAL SLEEVZ

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1 FLOW BAFFLES l VESSEL SIIELL g

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SPARGER I BEARItJC PAD

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i LOCATIOt1 OF BEARItJG PAD / REACTOR VESSEL GAP LOCATI0il 0F GAPS BETWEEfi BEARillG PADS AND REACTOR PRESSURE VESSEL WALL FIGURE 111-8

IV. REFERENCES j 1. BWR Feedwater Nozzle and Control Rod Drive Return Line Nozzle Cracking, NUREG-0619, U.S. Nuclear Regulatory Commission, November 1980.

2. GE Report, " Ultrasonic Examination of the Feedwater Nozzle Inner Radius and Bore at Nine Mile Point Unit One", PME No. 77-508-69, dated July 25, 1977 (UT procedures included in Appendix I) .

3. GE Letter, E. R. Egger to T. J. Perkins, dated August 30, 1979 with enclosures.

(

Subject:

In-service Ultrasonic Examination of Feedwater Nozzles at Nine Mile Point Unit One) ,

4. GE letter, D. L. Richardson to F. A. Hawksley, dated March 23, 1981 with enclosures.

(

Subject:

Ultrasonic Examination of the SE Feedwater Nozzle Inner Radius and Bore, Nine Mile Point, Unit One)

5. GE letter, D. L. Richardson to F. A. Hawksley, dated April 23, 1981 with enclosures.

(

Subject:

Ultrasonic Examination of the SW Feedwater Nozzle, Zones 2 and 3)

IV-1

6. GE Liquid Penetrant Examination Reports

a. April 21, 1981 - Initial PT of SE Nozzle Bore and Face

b. April 21, 1981 - Initial PT of SE End Brackets

c. April 21, 1981 - Interum PT of SE Nozzle Face

d. April 22, 1981 - Interum PT of SE Nozzle Face

e. April 24, 1981 - PT of SE Nozzle Bore and Face

f. April 24, 1981 - Final PT of SE Nozzle Bore and Face

7. GE Magnetic Particle Test Report, dated April 22, 1981, MT of SE Grindout Cavity at 1 O' clock.

8. GE letter, J. M. Morris to T. J. Perkins, dated May 4, 1981 with enclosures. (

Subject:

Specialized Eddy Current Examination of the Grind Out Cavity, Located on the ID of the Southeast Feedwater Nozzle)

9. NES letter, S. L. Foote to F. A. Hawksley, dated March 19, 1981 with enclosures.

(

Subject:

Evaluation of Feedwater Nozzle Inner Radius Examination) 10 NES letter, E. L. Anderson to F. A. Hawksley, dated March 21, 1981 with enclosures.

(

Subject:

Feedwater Nozzle Inner Radius Examination)

IV-2

. e e

o

11. NES Ultrasonic Examination Procedures, Document No.

80A2823 Rev. O, dated February 23, 1981. [

^

12. Niagara Mohawk Internal Correspondence, D. K.

l Greene to NMP-1 Licensing File, dated May 13, 1981. F l (

Subject:

NRC Telecon, Feedwater Nozzles) ,

I f

13. Niagara Mohawk Internal Correspondence, F. A. ,

l Ilawksley to R. Norrix, dated June 25, 1981 4

(

Subject:

Disposition of the SE Feedwater Nozzle UT Indication) l i

l

?

L IV-3 ,

6 V. APPENDICES 4

. .a s

APPENDIX A DESCRIPTION OF NES AND GE ULTRASONIC EXAMINATION PROCEDURES t

A. NES PROCEDURE The NES feedwater nozzle UT examination procedure was first used at Nine Mile Point Unit 1 in 1981. This

? procedure divided the nozzle inner radius and bore ,

surfaces into two zones as shown in Figure A-1. NES Zone 1 examinations are performed from the reactor vessel shell; NES Zone 2 examinations are performed -

from the nozzle barrel. NES Zone 1 and Zone 2  :

examinations overlap at the inside radius surface of ,

the nozzle.

Examinations performed from the reactor vessel shell are performed by attaching a specially designed lucite wedge, which conforms to the reactor vessel outside I radius, to an ultrasonic transducer such that the longitudinal beam angle is fixed. l i

Examinations performed from the nozzle barrel are performed using compound angle beam shear wave I i

techniques. In this case, a number of specially designed fixed compound angle lucite wedges.which conform to the outside radius of the nozzle barrel are used.

i l

l

~

i A-1 l

l I

( )

o B. GE PROCEDURE The GE feedwater nozzle UT examination procedures was used for the 1977 baseline and 1979 inservice inspec-tions at Nine Mile Point Unit 1. This procedure divides the nozzle inner radius and bore surfaces into three zones as shown in Figure A-2.

The GE Zone 1 examination is performed by attaching an ultrasonic transducer to a specially designed lucite wedge, which conforms to the reactor vessel outside radius, such that the longitudinal beam angle and the circumferential beam angle are fixed.

The GE Zone 2 examination is performed by attaching an ultrasonic transducer to a specially designed lucite wedge, which conforms to the outer diameter blend radius of the nozzle, such that the longitudinal beam angle and the circumferential beam angle are fixed.

The GE Zone 3 examination is performed by attaching an ultrasonic transducer to a specially designed lucite wedge, which conforms to the outside radius of the nozzle barrel, such that the circumferential beam angle is fixed.

A-2 l

e ..

0 E L SIDE EXAMINATION 1r f

%70*

ZONE 2 BARREL SIDE EXAMINATION [ ""

( ANGLE OF DEAM IS l..

VARIED WITl! DIPPERENT )

WEDGES) r E ~lf

+

E y

x iv

(,

t \J s zot7E2 _ 5*

0

4. rW NOZZLE NES UT INSPECTION ZONES FIGURE A-1

I e

ZONE 1 SHELL SIDE EXAMINATION 1 ZONE 2 RADIUS EXAMINATION %52L (FOR CLARITY, WEDGE ,

4 NOT SHOWN AT EDGE k ZONE 1 SHELL OF EXAMINATION ZONE) l SIDE EXAMINATION l l

ZONE 3 BARREL, " '

ZONE 2 RADIUS SIDE EXAMINATI EXAMINATION e'

' ,. ~

N6*

s17e \ ,

_. 55-A _ ZONE 1

r

+ u v, ,

( A ZONE 3 ZONE 2 N

T, FW NOZZLE

- - , ,e ) ,

, y ,

4 N. .

~22.-

ZONE 3 BARREL SIDE EXAMINATION GE UT INSPECTION ZONES FIGURE A-2

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