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JUL 171955
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f I would like to express our gratitude to you for meeting with the NRC l
investigators on September 1, 1983, and discussing your concern related to l
drilling holes through rebar in January 1983.
The Technical Review Team (TRT) has designated your concern as AC-15 for record keeping purposes and has investigated it.
The results of their investigation are attached and are being issued in a Supplemental Safety Evaluation Report.
We are sending the attached report to your last known address.
If you have any questions on our findings, please call me collect at (301) 492-7203.~ -
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,f FORM NRC47 (3 75) f NUCLEAR REGULATORY COMMISSION h
REQUEST FOR CERTIFIED AND REGISTRY M AILING C
8;EQUESTING OFFICE M AIL STATION TYPE OF M AILING REQUIRCD (Checx One)
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REGISTERED CERTIFTED
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ADD RESSEE INSTRUCTION
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Requesting Office:
l Prepare NRC-47, original only, for each item of mail to be _
Date Maded Date Madad registered or certified. Securely attach to letter and forward to Headquarters Mail Service Section.
Heedquarters Mail Savice Stadon:
Complete processing by assigning registry or certified number, date of mailing and then return form to office of orhin.
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M Jy g I would like to express our gratitude to you for meeting with the NRC investigators on September 1,1983, and discussing your concern related to drilling holes through rebar in January 1983.
The Technical Review Team (TRT) has designated your concern as AC-15 for record keeping purposes and has investigated it. The results of their investigation are attached and are being issued in a Supplemental Safety Evaluation Report.
We are sending the attached report to your last known address.
If y'ou have'~.
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any questions on our findings, please call me collect at (301) 492-7203.
Sincerely,
/
o an, Director manche eak P ject
Enclosure:
As sta ad cc:
M.E. Kline l
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', 1.
Allegation Cateaory:
Civil and Structural 15, Rebar Improperly Drilled 2.
A11ecation Number:
AC-13, AC-14, AC-15, AC-18 and AC-40 3.
Characterization:
holes were drilled through reinforcing steel (rebar)It is alleg allegations relating to:
The issue includes a.
the loan of rebar drills without proper documentation (AC-13) b.
(AC-14,AC-18,AC-40),andthe unauthorized cutting of rebar in n 4
c.
the unauthorized cutting of rebar used in the installation of th trolley process aisle rails in the Fuel Handling Building (AC 15 e
4.
Assessment cf Safety Stanificance:
contacted the The NRC Technical Review Team (TRT) his concerns. indtvidual who made allegations AC who made allegations AC-18, AC-40, and AC-15.
AC-13 concerns the. loan ~of rebar drills allegedly used for the a.
unauthorized cutting of rebar.
matter, the NRC Office of Investigation (OI) interviewed nineD rebar. These individuals provided sworn stat knowledge of this activity.
These statements are a part of OI Report A4-83-005 (May 20, 1983),
which concludes that "there was no testimony received indicating that holes were drilled or reb cut without proper documentation, and no evidence was found to ar was contradict the testimony of these individuals."
possible unauthorized cutting of rebar is discussed in a supplem One instance of to the OI report (September 7, 1983).
n below in relation to allegation AC-15. This instance is discussed Because the alleger.did not specificaMy identify who made unauthorized cuts of rebar, or where this cutting took place attempted to quantify the amount of rebar that allegedly was, cut the TRT without authorization.
In discussions with the TRT, the alleger estimated that approximately five percent of the diamond core d bits ordered by him were used in an unauthorized manner depending upon the extent of cutting required. estimat He further that the number would be in the thousands.be specific Although he could not Investigation of this issue indicated that 415 diamond core drill The NRC Region IV Using the actual number of drill bits purchased information provided by the alleger, the TRT estimated that the e
could be approximately 100 alleged unauthorized rebar cuts.
re and the fact that the structures consist primar reinforced concrete walls and slabs, the TRT determined that, if K-87 s
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a unauthorized rebar cutting occurred, the amount involved would have an inconsequential effect on the safety of the structures.
Allegations AC-14, AC-18 and AC-40 also raise question.s regarding the I
b.
unauthorized cutting of rebar, but do not identify specific locations.
During the course of. the NRC Region IV investigation of
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this matter, the alleger provided a log book which, it was reported, would identify the unauthorized and undocumented rebar cutting.
However, the Region IV inspector could not identify one rebar cut listed in the log that was not authorized.
The TRT also reviewed the log and came to the same conclusion.
In discussing this matter with the TRT, the alleger confirmed that g
there was documentation supporting "ninety nine and three quarter percent" of the rebar cuts identified in the log. As part of Report 83-27, the NRC Region IV investigator traced 32 authorizations, approximately half of the documents noted in the log for the rebar f,lj cutting. He found that in all cases rebar cuts were properly identified on a design change authorization (DCA) or on a component e'-
h modification card (CMC).
In addition, the rebar cuts were traced to and identified on specific building structural drawings, with the I;
corresponding authorizing document number. The TRT reviewed 10 CMCs lj and confirmed the findings of the Region IV investigation.
j; In reviewing authorizations in the log [ the TRT noted that certain h i CMCs involved a number of rebar cuts in one area, and selected these for review.
In one case, 7 different CMCs (3307, 3664, 3665, 3666, y;'
3667, 3668 and 3669) seemed to pertain to one area and accounted for h
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68 rebar cuts.
Upon reviewing the documentation, the TRT found that
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these cuts were made in a tunnel area in the Fuel Building.
(The alleger identified this as a location where a large number of rebar was cut.) However, the 68 cuts were arranged such that only 9 bars i
actually had been cut.
In another case, the log indicated 25 rebar cuts pertaining.to CMC 00979.
In this case, the TRT determined that all the cuts were made on one reinforcing bar in a support beam.
! l Finally, the log indicated eight rebar cuts pertaining to CMC 3022.All-l Once again, these eight cuts were to one bar in a support beam.
l le cuts were made in accordance with the rebar cutting criteria provided by Gibbs & Hill. These examples also illustrate the point that a
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large number of rebar cuts recorded.are not necessarily synonymous j
with an identical number of rebar actually being cut.
In all cases, one bar was cut a number of times, but adjacent bars were not.
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the cuts were arranged to minimize the overall effect on the strength i
of the structure.
The TRT estimates that approximately 335 rebar cuts are indicated in
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the alleger's log.
Discussions with the a11eger revealed that he i
believes he cut approximately five percent more rebar than was authorized, a number that corresponds to approximately 17 unauthorized rebar cuts.
As noted earlier, such a number would have little effect on the safety of the structures.
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Allegation AC-15 identifies a specific instance of the possible c.
unauthorized cutting of rebar.
In this case, a former Brown & Root employee stated he possibly drilled holes through rebar in a concrete floor without a component modification card-(CMC) or a design change authorization (DCA).
He explained that in January 1983 he drilled f
approximately 10 holes about 9 inches deep while installing 22 metal plates with a core drill.
He said the metal plates were used to secure the trolley process aisle rails located on the 810-foot, 6-inch floor level in Room 252 of the Fuel Handling Building.
The TRT inspected the trolley process aisle rails and its anchoring system and observed no violations of project drawings or specifications.
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(2323-S-0800 and 2323-5-0820)The TRT reviewed the reinforcement drawings determine the location of rebar.for the Fuel Handling Building to The drawing showed three layers of reinforcement in the upper part of the mat, which consisted of a No.
18 bar running in the east-west direction, in.the first and third l
layers, and a No. 11 bar running in the north-south direction, in the l
second layer.
The review of the reinforcement drawings (2323-5-0800 and 2313-5-0820) revealed that the layout of the e6st-west reinforcement and the trolley process aisle rails was such that'only one bar of the east-i west reinforcement could be cut by drilling holes for rail anchors.
However, if 9-inch holes were drilled, both layers of the No.18 l
reinforcing bar would be cut.
De' sign Change Authorization (DCA) No.
i 7401 was written for authorization to cut the uppermost No.18 bar at l
only one rail, but it did not reference the authorization to cut the l
lowermost No.18 bar.
sion bolts and baseplates could be moved in the east-west directionThe to avoid interference with the No.11 reinforcement running in the north-south direction.
The information described in DCA No. 7041 was substantiated by Gibbs & Hill calculations.
The DCA approval was based on the understanding that only the uppermost No.18 reinforce-ment would be cut.
If the 10 holes were actually drilled 9 inches deep, then the allegation that reinforcement was cut without proper authorization may be valid.
The OCA indicated that the holes were drilled to accommodate 1/2-inch Hilti bolts, which require a minimum embedment of 5-1/2 inches (as noted in Fig. 39, Sh. 5 of 5, attached to DCA-7041).
Since there was no need to drill the holes deeper than 5-1/2 inches, the alleger may not be correct in stating that tne holes were drilled 9 inches deep.
l Although the allegations discussed above, with the exception of AC-15 which requires further action, cannot be substantiated, the fact that such allegations were made indicated that there was no effective quality assurance program to oversee the issuance and use of diamond L
core drill bits.
The TRT interviewed the individual concerned about the loan of rebar drills without proper documentation and the unauthorized cutting of rebar at nonspecific locations to inform him of the TRT's finding.
This individual did not agree with certain TRT findings.
In
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particular, the alleger felt that the TRT's estimate of approximately
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120 unauthorized rebar cuts was much too low.
He believes that the number of drill bits ordered by him was in the thousands and that as much as 20 percent of the drill bits may have been used in an unauthorized manner.
It was also his opinion that the unauthorized cutting of rebar was not limited to his period of employment, but occurred for the duration of the project.
O As a result of these additional discussions with the a11eger, the TRT searched TUEC's files relating to the purchase of diamond drill bits and found that 1170 drill bits were purchased between January 13,
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1978 and January 14, 1980.
This number is more in agreement with the alleger's assessment and is higher than the previously reported number of 415. (IE Report 83-27). The TRT also found that there were i
a total of 3368 drill bits ordered from one manufacturer between January 13, 1978 and March 18, 1983.
After this period, other manufacturers supplied the drill bits.
Based on the usage through March 10, 1983, the TRT estimates that approximately 5000 diamond drill bits have been used to date on the project.
Assuming that 20 percent of these drill bits were used in an unauthorized manner and that each drill bit could be used to cut up to five rebars, the TRT estimates that there could be approximately 5000 alleged unauthorized rebar cuts.
I The TRT estimated that, depending upon the average length of rebar assumed, there are approximately 800,000 to 1,200,000 bars installed in all of the concrete structures. Thus, if 5000 bars were cut without authorization, they would represent approximately 0.'6% of the total rebar in the plant.
Even if all 5000 drill bits were usec" in an unauthorized manner it still would only represent 3% of the total rebar in the plant. Thus the percentage of rebar that could have been cut without proper authorization is low.
Since no information was supplied to the contrary,'.the TRT assumed that these unauthorized cuts, if-they did occur, were scattered throughout the plant and not concentrated in one localized area.
In addition as noted earlier, a s
large number of rebar cuts are not necessarily synonymous with an I
identical number of rebar actually being cut.
It is also noted that nuclear structures are very conservatively designed.
In addition to the conservative loads, load combinations,'and safety factors i
utilized in the design, it is the common practice of the design engineer to specify 5 to 10 percent more rebar than is actually required by his calculations.
This occurs because it is difficult to obtain the exact area of reinforcement required using standard bar sizes and standard bar spacing. The area of reinforcement is selected free charts which show the area provided for each b.t.r size at a given spacing.
Rather than underdesigning, the designer selects an area of reinforcement from the charts which is higher than that which is actually required.
In addition, because critical structures contain a large number of bars, they are not generally vulnerable to the random cutting of a small number of bars.
5.
Conclusion and Staff Positions: The TRT concludes that allegations AC-13, AC-14, AC-18 and AC-40 have no structural safety significance.
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l The allegat. ions were not specific as to who made unauthorized cuts of a.
rebar or where the cuts took place.
b.
The number of unauthorized rebar cuts alleged, if true, would have an inconsequential effect on the safety of the structures.
However, the results of these evaluations will be further assessed as a part of the programmatic review concerning procedures addressed under QA/QC Category.6, "QC Inspection." Therefore, the final acceptability of these evaluations will be predicated on the satisfactory results of the programmatic review of this subject.
Any adjustments to the existing l
conclusion of this evaluation resulting from the programmatic review will.
be reported in a supplement to this SSER.
Allegation AC-15 will remain open until the information requested of Texas Utilities Electric Company (TUEC) in " Actions Required" is provided.
The TRT attempted to contact the individuals who made allegations AC-18 and AC-15 to inform them of the TRT's findings.
The individual who made l
allegation AC-18 will be-informed of the TRT's findings by letter.
One of the two individuals involved in allegation AC-15 cannot be located; the TRT is still attempting to contact.the other. The TRT also contacted the individual who made allegations AC-13, AC-14, and AC-40 to discuss the TRT's findings pertaining to the concerns he raised in the first closure interview.
An interview was arranged; however, later the alleger indicated he did not want to meet with the TRT.
A letter will be sent to him informing him of the TRT's findings.
2 6.
Actions Required:
TUEC shall provide:
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Information to demonstrate that only the No.18 reinforcing steel in the first layer was cut, or 2.
Design calculations to demonstrate that structural integrity is maintained if the No.18 reinfo cing steel on both the first and third layers was cut.
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