IR 05000456/1987024
| ML20238A125 | |
| Person / Time | |
|---|---|
| Site: | Braidwood  |
| Issue date: | 09/02/1987 |
| From: | Danielson D, Norton J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | |
| Shared Package | |
| ML20238A090 | List: |
| References | |
| FRN-59FR979 50-456-87-24, 50-457-87-23, AC93-1-035, AC93-1-35, NUDOCS 8709090142 | |
| Download: ML20238A125 (6) | |
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U.S. NUCLEAR REGULATORY COMMISSION
REGION III
Reports No. 50-456/87024(DRS); 50-457/87023(DRS)
Docket Nos. 50-456; 50-457 Licenses No. NPC-72; CPPR-133 Licensee:
Commonwealth Edison Company Dost Office Box 767 Chicago, IL 60690 l
Facility Name: Braidwood Station, Units 1 and 2 Inspection At:
Braidwood Site, Braidwood, Illinois Inspection Conducted: June 25, 26, July 17 and August 18, 1987
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Inspector:
J. F. Norton
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Approved By:
D. H. Danielson, Chief
- 7 Materials and Processes Section Date Inspection Summary Inspection on June 25, 26, July 17 and August 18, 1987 (Reports No. 50-456/87024(DRS); 50-457/87023(DRS))
Areas Inspected:
Routine safety inspection of containment tendons.
(92706)
Results:
No violations or deviations were identified during this inspection.
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DETAILS l '.
Persons ~ Contacted Commonwealth Edison Compar.y (CECO)
E. Wendorf, PCD
.W. Bruns, PCD B. Acsi, PFE
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- C. ~Bedford,' Regulatory Assurance Supervisor
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Sargent and tendy Engineers (S&L).
S. Putman, Registered Structural Engineer
- Denotes those present at.the exit interview.
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Periodic Inspection of Containment Tendons Background
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Certain-tendons at Braidwood have a history of exhibiting water in the internals.of the tendons (in the grease and surrounding the stressed wires). Because of this, S&L and CECO recommended and implemented a periodic inspector program to monitor the tendons.
The last report on this inspection is dated February 2,1987. A portion of the subject report iT excerpted below:
Sargent & Lundy recommended that the 15 'iocp tendon anchorages which were found to nave water present durirm the initial August examination be re-examined in November 1986.
There are seven Unit I and eight Unit 2 Loop tendon anchorm.e involved. This recommendation corresponds with the. scheduled re-e amination of the 41 vertical tendons 'in which ten r.nchorages exnibited recurring water during the second examination of the vert'cals in May 1986.
There are six Unit 1 and four Unit 2 vertical tendon anchorages involved.
The following results are based on this November-December surveillance:
Vertical Tendons All 41 vertical tendon anchorages that initially had water present were re-examined during this third surveillance of vertical tendons.
Of the ten anchorages which exhibited recurring water during the second surve llance, only three anchorages were found to have water present this time. These three anchorages were all in Unit 2.
L Based upon these results, it can be stated that the surveillance
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effort is elim'nating water from the vertical tendon system.
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L addition, no corrosion was observed on the anchorheads or wires.
This indicates that the grease system is performing its interided function.
l Hoop Tendons All 15 hoop. tendon anchorages that initially had water present were re-examined during this second surveillance of hoop tendons. These 15 anchorages all exhibited recurring water this time. The quantity of water varied from a trace to 4-5 gallons.
In addition, no corrosion was observed on the anchorheads or wires.
Based upon these results, it can be stated that the grease system is performing its intended function.
In addition, surveillance efforts to date ht"e yet to indicate an elimination of water from the hoop tendon system.
Followup Activities We recommend that another anchorage surveillance be performed on all tendons which were wet in the November-December 1986 surveillance.
In addition, during the upcoming May 1987 initial inservice inspection of Unit 1, we have the following recommendations:
Designate Tendon 2AB as the hoop tendor, for wire removal and include Tendon 2CB as an additional hoop wire removal tendon.
Tendon 2AB has exhibited water recurrence at both the A and B anchorage based on two surveillance. Tendon 2CB is located between two tendons with recurring water and was found dry during the initial surveillance.
Designate Tendon V114 as the vertical tendon for wire removal.
This tendon has previously exhibited water recurrence, but durirg the most recent third surveillance was four,4 dry.
Subsequently, two tudons were de-tensioned and inspected for head cracking and rust /coi rosion potential. The Engineering Reports are excerpted and the sal.ent parts are as follows:
a.
Notes of Examination - June 25 and 26, 1987 Braidwood Nuclear Plant Unit 1 Containment Post Tensioning System Anchorhead THOSE PRESENT:
W. Bruns
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K. Buzek
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Commonwealth Edison Company (CECO)
B. Tanouye
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J. Norton
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Nuclear Regulatory Commission (NRC) - Region III l
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'. 4 C.; Brooks --
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Precision Surveillance Corporation-J. T. Louden
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S. F. Putman
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Sargent & Lundy (S&L)
J. R. Vannier )
Purpose:
The purpose of this examination was to determine that the anchorhead.
l was free of-any cracks and to determined the extent of corrosion.
Conclusions:
Based on this anchorhead examination, we have the following conclusions:
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The anchorhead had no cracks.
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There was some scattered light surface rusting detected mostly on the inside of the holes.
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The anchorhead exhibited scratches on the bearing surface which are the result of normal wire insertion during installation.
Discussion _:
Mr. B. Tanouye requested the writet; to inspect the bearing surface side of'the field anchorhead on hoop Tendon 2BA using an 0lympus.l.7 mm diameter by eight inch long borescope.'. Tendon 2BA-of Unit I was de-tensioned for this examination and thoroughly.
cleaned using a solvent-compressed air method.
Borescopic examina-tion was performed on June 25, 1987, with only abcut a one foot distance between the anchorhead backside and the concrete wall.
Referring to Attachment A, the borescope was guided down row "1" from the first to the last tendon wires, then row "2", etc., up to row "14" except that near the center of the anchorhead the final tendon wires were 'not always reached. This method was repeated, but using spaces on rows 60 to the previous ones. Thus rows "A" through "0" were examined. Reddish brown light surface rust was noted in some ligaments between the wire holes. The wires exhibited some areas of corrosion. The wire corrosion condition is documented in PSC's report, b.
Notes of Examination - July 23, 1987 Braidwood Nuclear Plant Unit 1 Cont &inment Post Tensioning System Anchorheaa THOSE PRESENT:
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W. Bruns
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Commonwealth Edison Company (CECO)
W. Liu
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Nuclear Regulatory Commission (URC) - Region III
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C. Brooks
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Precision Surveillance Corporation (PSC)
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J. T. Louden
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S. F. Putman
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Sargent & Lundy (S&L)
J. R. Vannier )
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Purpose:
The purpose of this examination was to determine that the anchorhead was free of any cracks and to determine the extend of corrosion.
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Conclusions:
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The anchorhead had no cracks.
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There was some scattered light surface rusting detected on the l
ligaments.
3.
The anchorhead exhibited scratches on the bearing surface which are the result of normal wire insertion during installation.
Discussion:
Mr. W. Bruns requested the writers to inspect the bearing surface side of the field anchorhead on hoop Tendon 1AC using an Olympus 1.7 mm diameter by eight inch long borescope. Tendon 1AC of Unit I was de-tensioned for this examination and thoroughly cleaned using a solvent-compressed air method. Direct visual borescopic examination was performed on July 23, 1987, with about a two foot distance between the anchorhead backside and the concrete wall. Referring to Attachment A, the borescope was guided down row "1" from the first to the last tendon wires, then row
"2",
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up to row "15" Except that near the center of the anchorhead the final tendon wires were not always reached. This metr - ' was repeated, but using spaces on rows 60 to the previou; nes. Thus, rows "A" through "0" were examined.
Reddish brown lignt surface rust was noted in some ligaments between the susveillances. The wires exhibited some areas of corrosion.
The wire corrosion condition is documented in PSC's report.
Conclusion The periodic inspection program needs to be continued, and followed
by HRC during routine inspections.
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Exit Interview The exit interview was accomplished by telephone en August 24, 1987.
The inspector summarized the purpose and findings of the inspection.
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The licensee acknowledged the findings as reported herein. The inspec
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discussed the report's likely informational content with respect to documents or processes reviewed b/;the inspector..The licensee did not identify any such documents / processes as proprietary.
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