ML19260A117
| ML19260A117 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 06/19/1972 |
| From: | Folson S, Howard E, Varela A NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | |
| Shared Package | |
| ML19260A116 | List: |
| References | |
| 50-289-72-08, 50-289-72-8, NUDOCS 7910290735 | |
| Download: ML19260A117 (9) | |
See also: IR 05000289/1972008
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U. S. ATOMIC ENERGY COMMISSION
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DIRFOTORATE OF REGULATORY OPERATIONS
REGION I
2_
RO Inspection Report Po. 50-289/72-08
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Subject:
Metropolttan Edison Company
Three Mile Island Unit 1
License No. CPPR-40
Location: Three Mile Island (near Middletown)~
Priority
Category
B
Type of Licensee:
Type of Inspection: Special, Unannounced (Ring Girder Repair)
Dates of Inspes tion:
April 27-28, 1972
Dates of Previous Inspection:
April 7, 1972
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Principal Inspector:
S. A. Fo om Re
or Inspector
Date
Accompanying Inspectors:
i. 'M
I~ I # ~ 7 b
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(Inspection Ferformed B'/)
A.'A. Varela, Reactor Inspector
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Other Accompanying Personnel:
NONE
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Reviewed By:
Date
E. M. Howard, Chief, Reactor Construction Br. , RO:I
Proprietary Information:
NONE
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SECTION I
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Enforcement Action
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None
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Licensee's Aerion on Previously Identified Enforcement Matters
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None
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Unresolved Items
Concrete voids have been identified in the South 180" section of the
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containment building ring girder.
Construction joints are also mis-
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loc ~ated.
The licensee has not reported results of the investigation
of these items to Licensing.
(?ection II, Paragraph 2)
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Status of Previously Identified Unresolved Items
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Repair is continuing on ring girder concrete voids in the North 1800
section of the containment building.
Repairs on Segments I and II,
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totalling 900, have been completed and concrete excavation, rebar
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removal, and tendon conduit repair is underway on Segment III.
This
item remair.s unresolved.
(Section II, Paragraph 1)
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Design Changes
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Not applicable.
Unusual Gecurrences
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None
Persons Contacted
Met Ed/GPU
M.
Stromberg, Site QA Supervisor *
W. Gunn, Project Engineer
J. Wright, Resident Civil Engineer *
R. Neidig, Assistant Civil Engineer +
J. Conr.elly, Assistant Civil Engineer *
- Attended Management Interview
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UE&C
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R. Moyer, QC SiTervisor*
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D. Lambert, QC Engineer *
P. Dailey, QC Structural *
J. Malvin, Lead Inspector, Structural
W. Haugen, Ring Girder Repair Supervisor
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R. Hawley, Assistant Ring Girder Repair Supervisor
J. McKee, Assistant Project Superintendent'
Management Interview
A.
The inspector quoted from DL's letter of March 1, 1972 on condi-
tions for approval of the North 1800 ring girder repair and in-
' quired when the licensee would provide e. commitment to fully
implement the six procedures outlined in the enclosure to the
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letter.
The licensee answered that a reply could be expected in
about a month and that it would commit Met Ed to five of the
procedures but take exception to Item No. 2 regarding preparation
and storage of six samples of concrete-epoxy-concrete joints.
B.
The inspector stated he observed wholesale rebar removal in
Segment III on the North 1800 ring girder repair for concrete
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excavation without attempt to salvage any. He inquired if CAI
gave prior approval for rebar removal, and if approval documenta- -
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tion for replacement was available.
The licensee rep 1ted that the approved procedure CCP-9 provides
for removal of rebar to give access necessary for removal of un-
sound concrete, and, since rebar replacements will conform to ori-
ginal design using cadweld splicing, special approval by GAI is not
required.
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C.
Regarding voiding and unconsolidation'on the South 1800 portion of
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the ring girder, the inspector asked when the licensee would pre-
sent a report to DL on the conditions.
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The licensee replied that the investigation following procedure
CCP-9 is underway, using one-inch ciameter drill cores for con-
crete soundness and modified by GAI to use two-inch diameter drill
cores for construction joint location and bonding study.
The li-
- Attended Management Interview
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censee added that, pending complete core analysis and further
advice from GA'., no date could be given when the report to DL
would be isc ted.
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D.
The inspector recalled that during the inspection of March 9,
1972, apparent unsatisfactory cadwelding had been observed on
the North 1800 ring girder repair. At that inspection, the licensee
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agreed to review the cadwelding program for adequacy. The in-
spector stated that during this inspection, he found satisfactory
evidence of program improvement; however, due to no cadwelding at
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this time, he would leave this as an open item.
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SECTION II
. Additional Subiaets Inspected Not Identified in Section I, Where No
Deficiencies ot, Unresolved Items Were Found
None
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Details of Subjects Discussed in Section I
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1.
North 180 Ring Girder Repair
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a.
Status of Repairs on Ring Girder North 180
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Repair work was observed to consist entirely of concrete
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excavation and rebar removal on three 300 Segment III areas.
The most easterly area was farthest advanced and was jack-
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hammer probed about every four square feet for verification
of sound concrete.
Final concrete chipping with a 30 pound
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hand tool around stubs of reinforcing steel was observed in
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progress in the easterly and north areas. Heavy concrete exca-
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vation on the westerly Segment III was proceeding with the 60
pound jack-hammer between tendon conduits.
Practically all
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rebar including most of the dome spirals were observed to have
been removed to facilitate excavation.
Excavation on Segment
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III, east area, was observed to have been taken to the depth
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from outside the face of the ring girder to vertical construction
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joint between pours 3 and 4.
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b.
Su= mary of Repairs Complated
See Page 6 for Tabulation.
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180 North Summary of Repairs Completed
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Spiral Re-
Concrete
Date of
' Concrete
Cadwelds
placements'
Core
Strair.
Cubic Yards
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Poiar
Segment
Lift _ Location *
In Place Rejected Butt Nicks # of Iloops
lloles
Gages
Placed
3/2
15
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1
180 /93
122
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8(2)
g(1)
24
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2
180 /93
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300 III
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93 /63
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2/16
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630/33
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3/20
30
II
2
63"/33
266
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3/29
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II
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63 /33
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30" III
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33 /03
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3/23
300
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03 /3330
266
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12(3) 0
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3/27
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03 /133
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30 III
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333 /303"
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303 /288
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3/29
150 II
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303 /288
159
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303 /288
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- Azimuth Counterclockwise
(1) Repair cut out to provide access for other work.
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(2) Repairs cut out and replaced with full length bars or cadwelds after five were rejected.
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(3) Itepairs rejected on visual inspection snd/or radiographs and replaced by 'cadwelds.
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2.
Voids in South 180 Ring Girder
a.
Investi mtion
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In La Report No. 50-289/72-07 (inspection of April 7,1972) the
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inspector stated that UE&C has issued Deficiency Report No.
0447, dated April 5, 1972, on the South 1800 portion of the
ring girder where voids and unconsolidation were found. A
supplement to the Deficiency Report was issued on April 12,
1972. The supplement states that the horizontal construction
joint, which should have occurred at Elev. 446' - 9" varies by
as much as two feet in elevation.
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The inspector was informed at this inspection that a field
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change was issued to Construction Procedure No. CCP-9, Change
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No. 2, dated April 26, 1972. The reason for the change was
due to the discovery of unconsolidated concrete in the outboard
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sections of the South 180 half of the ring girder pours 3 and
4
Exploratory steps in advance of a new (repair) section were
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undertaken. The exploratory method involves the following:
(1) Remove debris and clean surface of exposed concrete by
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chipping from, and near surface areas, honecemb and dirt
pocket inclusions.
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(2) Remove honeycomb within limits of guidelines set forth in
" Attachment E" to CCP-9.
(3) Conduct below surface verification of sound concrete by
taking core drill samples.
(4) Explore construction joints by drilling one-inch and two-
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inch diameter core holes between pours 2 and 3, and 3 and 4
to determine degree of bond at the construction joint, two-
inch holes to penetrate only 24 inches in first phase.
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(5) Evaluation of cores, recommendations, and rate of continued
sampling shall be made periodically by GAI.
The inspector was infor=ed that, at a meeting on April 25, 1972,
between Met Ed, UE&C, and GAI, the latter reviewed results of
the investigation to date and specified drilling the two-inch
holes deeper because poor bond was encountered in the first 24
inches drilled.
b.
Insoection of Two-Inch Diameter Drill Cores - South 1800
See Page 8 for Chart..
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Core
Drill Hole Location
Length *
Remarks and Bond Condition
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Below Upper #124 (Cone t.
34"
-Drilled and redrilled in two at-
joint is mislocated
7" low)
tempts due to joint not horizontal;
both exhibit no bond due to laitance.
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At Lower #334 (Const. joint
37"
Outside 25" no bona due to unclean
is mislocated d'4" high)
joint; inner 12" well bonded.
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_At Lower #329 (Const. Joint
38"
Entire length exhibits no bond due
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is mislocated ^f7" high)
to laitance.
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At Lower #315 (Const. joint
36"
Drilled 12" horizontal, ran out of
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is mislocated es6" high)
joint; redrilled twice off horizontal
to follow joint; entire joint exhibits
no bond due to laitance and dirt
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(wood, wire, and thin plastic film).
lS. At Lower #301 (Const. joint
46"
Drilled 24" horizontal, ran out of
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is mislocated /v6" high)
joint; redrilled off horizontal to
follow joint; except for 4" in re-
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drill, all cores exhibit poor bond
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due to laitance.
- Measured from outside surface ring girder at construction joint.
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i NOTE:
1.
Total two-inch diameter holes drilled to date is ten. Total one-inch
holes is 24
2.
Following the last RO inspection on April 7,1972, ,urface " dirt"
pockets were chipped out of construction joints, and these exposed un-
clean joints. Drill program with two-inch diameter cores were under-
taken to see if interior of joint was clean.
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3.
These holes are aligned with tendons. They are not radial, but
are horizontal.
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3.
Improvement in cadweld Splice Quality Control Program
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RO Inspectica Report 72-04 identified unsatisfactory conditions
observed in cadweld splicing. Although the applicant, at that
time, stated that a number of deficiencies observed by the in-
spector had already been identified as rejectable by the con-
tractor's inspectors, he acknowledged some difficulty in main-
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taining desired cadwelding quality.
The applicant agreed to re-
view the cadwelding quality control program for adequacy.
On
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March 13, 1972, the inspector was informed * hat a Cadweld Rebar
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Splice Company representative had been callsi to the jobsite
for retraining of cadweld operators, and that an additional cad-
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weld inspector had been trained to provide full t'ime inspection on
,both shifts. The following items were ascertained at this' inspection
which verify that the applicant has made a concerted effort to up-
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grade cadweld operators' technique, and cadweld
inspection and
quality control requirements.
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a.
Conversation with UE&C assistant construction superintendent
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verified retrain 1'.tg of cadweld operators.
b.
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Conversation with UE&C QC Supervisor, R. Moyer, verified that
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retraining of inspectors and QC personnel included a review of
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cadweld literature on the process of cadwelding and re-indoctri.na-
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tion on the items in the cadweld checklist of requirements.
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c.
Specialized training of an additional cadweld inspector to pro-
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vide full time inspection on the night shift.
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QC personnel and inspectors were present at retraining of cad-
weld operators
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