ML102920665: Difference between revisions
StriderTol (talk | contribs) (Created page by program invented by StriderTol) |
StriderTol (talk | contribs) (Created page by program invented by StriderTol) |
||
(2 intermediate revisions by the same user not shown) | |||
Line 3: | Line 3: | ||
| issue date = 10/19/2010 | | issue date = 10/19/2010 | ||
| title = Response to Disputed Notice of Violation (NOV) 05000391/2010603-08 | | title = Response to Disputed Notice of Violation (NOV) 05000391/2010603-08 | ||
| author name = Ogle C | | author name = Ogle C | ||
| author affiliation = NRC/RGN-II/DCI | | author affiliation = NRC/RGN-II/DCI | ||
| addressee name = Bhatnagar A | | addressee name = Bhatnagar A | ||
| addressee affiliation = Tennessee Valley Authority | | addressee affiliation = Tennessee Valley Authority | ||
| docket = 05000390 | | docket = 05000390 | ||
Line 14: | Line 14: | ||
| page count = 8 | | page count = 8 | ||
}} | }} | ||
See also: [[ | See also: [[see also::IR 05000391/2010603]] | ||
=Text= | =Text= | ||
{{#Wiki_filter: | {{#Wiki_filter:UNITED STATES | ||
NUCLEAR REGULATORY COMMISSION | |||
REGION II | |||
MARQUIS ONE TOWER | |||
245 PEACH TREE CENTER AVENUE, NE | |||
ATLANTA, GEORGIA 30303-1257 | |||
October 19, 2010 | |||
EA-10-195 | |||
Tennessee Valley Authority | |||
Mr. Ashok S. Bhatnagar | |||
Senior Vice President | |||
Nuclear Generation Development and Construction | |||
Tennessee Valley Authority | |||
6A Lookout Place | |||
1101 Market Street | |||
Chattanooga, TN 37402-2801 | |||
SUBJECT: RESPONSE TO DISPUTED NOTICE OF VIOLATION (NOV) | |||
05000391/2010603-08 | |||
Dear Mr. Bhatnagar: | |||
Thank you for the TVA letter dated September 7, 2010, in response to our NOV | |||
05000391/2010603-08 dated August 5, 2010. The Notice described a violation that was | |||
identified during an inspection conducted by the Nuclear Regulatory Commissions (NRCs) | |||
Division of Construction Inspection (DCI). | |||
In the response, TVA disputed NOV 05000391/2010603-08. As base for its denial TVA | |||
indicated the following: | |||
* Westinghouse seismically tested the120VAC Vital Instrument Power Board assembly in | |||
1974 in a configuration which duplicated the actual configuration in the plant. | |||
* Commercial grade replacement breakers were dedicated in 1992 using the guidance of | |||
IEEE 344-1975 Section 6.4, Device Testing. | |||
* The calculated natural frequencies of the front cover panel show it to be rigid. The rigid | |||
clamping arrangement of rear retaining angles and front cover panel do not introduce any | |||
additional flexibility that would require replication of the 1974 testing. The 1974 and 1992 | |||
tests demonstrate the original board and breakers remain seismically qualified. | |||
* Subsequent modification to the commercial grade circuit breakers in 2008 were evaluated | |||
as like-for-like and the breakers remained seismically qualified. Calculation WCG-ACQ- | |||
1004 analyzed the effects that were introduced by the modification, demonstrated an | |||
adequate review for suitability of application, and analyzed the impact on other components. | |||
After review and consideration of TVAs response, the NRC has concluded that, for the reasons | |||
given in the enclosure to this letter, the violation occurred as stated in NOV 05000391/2010603- | |||
08. The violation involves the failure to accomplish activities affecting quality in accordance with | |||
10 CFR 50 Appendix B. You are required to provide an additional response in accordance with | |||
10 CFR 2.201. The violation was categorized at Severity Level IV and will remain open until the | |||
NRC has verified implementation of TVAs corrective actions during a subsequent inspection. | |||
A. Bhatnagar 2 | |||
In accordance with 10 CFR 2.390 of the NRCs Rules of Practice, a copy of this letter and its | |||
enclosure will be available electronically for public inspection in the NRC Public Document | |||
Room or from the Publicly Available Records (PARS) component of the NRCs document | |||
system (ADAMS). Adams is accessible from the NRC Web site at http://www.nrc.gov/reading- | |||
rm/adams.html (the Public Electronic Reading Room). | |||
If you have any questions regarding this correspondence, please contact Mark Lesser at | |||
404-997-4460. | |||
Sincerely, | |||
/RA/ | |||
Charles Ogle, Director | |||
Division of Construction Inspection | |||
Docket Nos.: 50-392 | |||
License Nos.: CPPR-92 | |||
Enclosure: NRC Evaluation and Conclusion | |||
ML102920665 XG SUNSI REVIEW COMPLETE | |||
OFFICE RII:DCI RII:DCI RII:EICS OE NRR RII RII | |||
SIGNATURE MSL CRO CFE e-mail e-mail TNF GC | |||
NAME M. Lesser C. Ogle C. Evans G. Gulla K. Manoly T. Fanelli G. Crespo | |||
DATE 10/6/10 10/19/10 10/6/10 10/8/10 10/6/10 9/29/10 9/28/10 | |||
E-MAIL COPY? YES NO YES NO YES NO YES NO YES NO YES NO YES NO | |||
A. Bhatnagar 3 | |||
cc w/encl: | |||
Mr. Gordon P. Arent Mr. M.J. Hellstern | |||
Manager General Manager | |||
New Generation Licensing NGDC Governance & Oversight | |||
Nuclear Generation Development Tennessee Valley Authority | |||
and Construction 3A Blue Ridge Place | |||
WBN Nuclear Plant 1101 Market Street | |||
P.O. Box 2000 Chattanooga, Tennessee 37402-2801 | |||
Spring City, Tennessee 37381 | |||
Mr. R.M Krich | |||
Mr. Masoud Bajestani Vice President | |||
Vice President Nuclear Licensing | |||
WBN Unit Two Tennessee Valley Authority | |||
WBN Nuclear Plant 3R Lookout Place | |||
Tennessee Valley Authority 1101 Market Street | |||
P.O. Box 2000 Chattanooga, Tennessee 37402-2801 | |||
Spring City, Tennessee 37381 | |||
Mr. E.J. Vigluicci | |||
Mr. Michael K. Brandon, Manager Assistant General Counsel | |||
Licensing and Industry Affairs Tennessee Valley Authority | |||
WBN Nuclear Plant 6A West Tower | |||
Tennessee Valley Authority 400 West Summit Hill Drive | |||
P.O. Box 2000 Knoxville, Tennessee 37402 | |||
Spring City, Tennessee 37381 | |||
Lawrence E. Nanney, Director | |||
Mr. Preston D. Swafford Tennessee Department of Environmental | |||
Chief Nuclear Officer Health and Conservation | |||
and Executive Vice President Division of Radiological Health | |||
Tennessee Valley Authority 3rd Floor, L&C Annex | |||
3R Lookout Place 401 Church Street | |||
1101 Market Place Nashville, TN 37243-1532 | |||
Chattanooga, Tennessee 37402-2801 | |||
Mr. D. E. Grissette | |||
County Executive Site Vice President | |||
375 Church Street WBN Nuclear Plant | |||
Suite 215 Tennessee Valley Authority | |||
Dayton, Tennessee 37321 P.O. Box 2000 | |||
Spring City, Tennessee 37381 | |||
W.R. Crouch, Manager | |||
WBN Unit 2 Licensing County Mayor | |||
Watts Bar Nuclear Plant P.O. Box 156 | |||
Tennessee Valley Authority Decatur, Tennessee 37322 | |||
P.O. Box 2000 | |||
Spring City, Tennessee 37381 Senior Resident Inspector | |||
WBN Nuclear Plant | |||
Mr. Gregory A. Boerschig U.S. NRC | |||
Plant Manager, WBN Nuclear Plant 1260 Nuclear Plant Road | |||
Tennessee Valley Authority Spring City, Tennessee 37381-2000 | |||
P.O. Box 2000 | |||
Spring City, Tennessee 37381 | |||
A. Bhatnagar 4 | |||
Letter to Ashok S. Bhatnagar from Charles R. Ogle dated October 19, 2010 | |||
SUBJECT: RESPONSE TO DISPUTED NOTICE OF VIOLATION (NOV) | |||
05000391/2010603-08 | |||
Distribution w/encl: | |||
L. Raghavan, NRR | |||
S. Campbell, NRR | |||
P. Milano, NRR | |||
C. Evans, RII | |||
L. Douglas, RII EICS | |||
R. Haag, RII, DCP | |||
W. Bearden, RII, WBN Unit 2 SRI | |||
E. Guthrie, RII DRP | |||
R. Monk, RII WBN Unit 1 SRI | |||
OE Mail (OEMAIL) | |||
PUBLIC | |||
cc email distribution w/encl: | |||
Greg Scott | |||
Tennessee Valley Authority | |||
Electronic Mail Distribution | |||
NRC EVALUATION AND CONCLUSION | |||
The violation was identified during an inspection conducted by the Nuclear Regulatory | |||
Commissions (NRC) Division of Construction Inspection (DCI) at Watts Bar Nuclear Station | |||
Unit 2 in Spring City Tennessee. TVA disagreed with the violation by letter dated | |||
September 7, 2010, and provided the following bases: | |||
* Westinghouse seismically tested the120VAC Vital Instrument Power Board assembly in | |||
1974 in a configuration which duplicated the actual configuration in the plant. | |||
* Commercial grade replacement breakers were dedicated in 1992 using the guidance of | |||
IEEE 344-1975 Section 6.4, Device Testing. | |||
* The calculated natural frequencies of the front cover panel show it to be rigid. The rigid | |||
clamping arrangement of rear retaining angles and front cover panel do not introduce any | |||
additional flexibility that would require replication of the 1974 testing. The 1974 and 1992 | |||
tests demonstrate the original board and breakers remain seismically qualified. | |||
* Subsequent modification to the commercial grade circuit breakers in 2008 were evaluated | |||
as like-for-like and the breakers remained seismically qualified. Calculation WCG-ACQ- | |||
1004 analyzed the effects that were introduced by the modification, demonstrated an | |||
adequate review for suitability of application, and analyzed the impact on other components. | |||
A. Specific Bases for Disputing NOV 05000391/2010603-08 | |||
In its letter of September 7, 2010, TVA disagreed with the NRCs conclusion regarding the 1992 | |||
qualification of circuit breakers and subsequent deficient equivalency evaluation at Watts Bar | |||
Unit 2. | |||
TVA cited the following as bases for disputing the NRCs conclusion that a violation occurred: | |||
1. Westinghouse seismically tested the 120VAC Vital Instrument Power Board assembly with | |||
Heinemann Model CF2-Z51-1 circuit breakers in 1974, mounted in place solely by clamping | |||
pressure applied by the front cover pushing twelve breakers against the rear angle supports. | |||
There were no additional screws to secure the breaker to the frame. This configuration | |||
duplicated the actual configuration in the plant. | |||
2. Commercial grade replacement breakers were dedicated in 1992 by attaching an individual | |||
breaker to the vibratory source with bolting. IEEE 344-1975 section 6.4, Device Testing, | |||
allows a device, intended to be mounted on a panel, to be mounted directly to the shake | |||
table if the in-service excitation can be simulated. A 3g input motion (which exceeded the | |||
2.72g highest measured acceleration [seismic demand] in the 1974 test) was applied. | |||
3. The retention of breakers in the as-constructed board assembly is by a clamping | |||
arrangement provided by two rear retaining angle iron members and the front cover panel. | |||
The calculated natural frequencies of the front cover panel in the three directions were in | |||
excess of 33 Hz and rigid. The rigid clamping arrangement of rear retaining angles and the | |||
front cover panel do not introduce any additional flexibility that would require replication of | |||
the 1974 testing. The 1974 and 1992 tests demonstrate the original board and breakers | |||
remain seismically qualified. | |||
4. Subsequent modification to the new breakers in 2008 added a Micarta plate and bolts to | |||
attach it. Calculation WCG-ACQ-1004 addressed the qualification of the circuit breakers | |||
with the Micarta plate and concluded that the component (i.e., circuit breaker) remained | |||
seismically qualified under like-for-like conditions per the 1992 seismic qualification device | |||
2 | |||
test. Calculation WCG-ACQ-1004 analyzed the effects that were introduced by the | |||
modification, demonstrated an adequate review for suitability of application, and analyzed | |||
the impact on other components. | |||
B. NRC Evaluation of Licensees Response | |||
The NRC carefully reviewed TVAs response and concludes that the violation occurred as | |||
stated in the Notice of Violation. The bases for this determination are as follows: | |||
1. The staff was unable to substantiate TVAs assertion that the 1974 test replicated the | |||
mounting configuration in the plant. The staffs review of the 1974 test records and | |||
configuration drawings revealed conflicting and inconsistent information. TVA cites the 1974 | |||
Westinghouse qualification and it references Westinghouse drawings CO-33419-MKE-M2 | |||
and M3 for the as-constructed configuration of the 120VAC Vital Instrument Power Board | |||
assembly. The Westinghouse drawings are inconclusive in determining if fasteners secured | |||
the circuit breakers and incorrectly show the orientation of the angle iron supports and the | |||
profile of the front cover plate. TVA drawing 45N7OI-4 R2 also depicts the as-constructed | |||
Watts Bar configuration of the 120VAC Vital Instrument Power Board assembly. The | |||
method of securing the circuit breakers, angle iron supports for the back of the breakers, | |||
and the profile for the front cover plates shown in the two sets of drawings are different. | |||
Drawing 45N7OI-4 R2 shows fasteners (screws or bolts) securing the circuit breakers to the | |||
rear angle iron supports, which are not in the as-constructed configuration, but accurately | |||
shows the orientation of the angle iron supports and the profile of the front cover plates that | |||
clamp the circuit breakers against the angle iron supports. Additionally the inside face of the | |||
front cover plate of the existing Watts Bar power boards has stiffening supports both | |||
vertically and horizontally on each panel. Neither the Westinghouse nor the TVA drawings | |||
show these supports in the drawings. TVA has not reconciled these differences. The staff | |||
was unable to verify that the existing Watts Bar 120VAC Vital Instrument Power Board | |||
assembly configuration is the same as the 1974 qualification test configuration. | |||
2. IEEE-344-1975, for the commercial grade dedication testing, Section 6.1.1, Mounting, states | |||
in part, for the equipment to be tested, the mounting method shall be the same as that | |||
recommended for actual service. TVA incorrectly cites IEEE 344-1975; Section 6.4 which | |||
allows components mounted on a panel or plate, i.e. flat surfaces, (flat doors, flat top, flat | |||
back, or flat sides), without any other interposing parts that could interfere with those parts | |||
to be mounted directly to a seismic test table fixture. Mounting such components to a test | |||
table on a simulated flat plate instead of the actual panel, in that case, would adequately | |||
simulate the mounting of those types of components. The applicant described the in-service | |||
mounting in their response as a 36 front panel with two horizontal angle iron supports in the | |||
rear and that the breakers were held in place solely by the clamping pressure applied by the | |||
front cover pushing the twelve breakers against the rear angle supports. The circuit | |||
breakers described by the applicant do not represent components mounted on a panel that | |||
can be tested in accordance with Section 6.4 of IEEE-344. Furthermore, the 1992 | |||
qualification report specified that it applies only to circuit breakers being secured by | |||
fasteners. The 1992 qualification report for the circuit breakers stated that they were | |||
mounted for testing with screws, to a test table plate, in a manner that simulates the normal | |||
in-plant mounting. The TVA drawing 45N7OI-4 R2 with the error depicting fasteners was | |||
created in the 1970s and was available for the 1992 qualification personnel. TVA has not | |||
adequately resolved these inconsistencies. | |||
3 | |||
3. TVA did not support their assertion that the front cover panel is rigid and that the clamping | |||
arrangement of rear retaining angles in combination with the front cover panel are rigid. | |||
TVA in its response letter stated, The calculated natural frequencies of the front cover panel | |||
in the three directions were also in excess of 33 Hz and rigid. When asked to produce the | |||
calculation for examination, TVA stated that the calculation was informal and not retained | |||
and therefore could not be presented for examination. Furthermore, according to drawings | |||
CO-33419-MKE-M2 & M3 the 120VAC Vital Instrument Power Boards construction consists | |||
of panels and angle iron supports that are bolted together. The front cover panels are | |||
bolted through threads in the steel angle iron. IEEE 344-1987 clarifies that, such cabinets | |||
with bolted doors or panels, produce impacts, rattling, chatter, or banging and these impacts | |||
are transmitted throughout the equipment and result in increased acceleration levels at | |||
frequencies much higher than the original frequencies imposed by the shake table. A low | |||
frequency input thereby produces high-frequency responses that may adversely affect | |||
devices mounted in the equipment and must be considered in their qualification. Therefore, | |||
an engineering analysis was necessary to ascertain the adequacy of the power boards and | |||
circuit breakers; however, TVA did not perform an engineering analysis nor provide an | |||
adequate basis that supports a conclusion that the panel arrangement is rigid and not | |||
flexible. | |||
4. TVA did not perform an adequate evaluation to support a conclusion that the 2008 | |||
modification of the newest circuit breakers are like-for-like replacements to those circuit | |||
breakers tested in 1974 or 1992. The new circuit breakers were determined by TVA, on or | |||
before July 2008, to be different in dimension from the circuit breakers dedicated in 1974 or | |||
1992 in that they no longer fit into the 120VAC Vital Instrument Power Boards by the | |||
clamping arrangement and had to be modified to fit. Since the new circuit breakers are field | |||
modified with the Micarta plate to fit into the 120VAC Vital Instrument Power Boards, the | |||
new circuit breakers are not like-for-like to the prior circuit breakers. Before September 7, | |||
2010 TVA had never determined the critical characteristics necessary to enable the circuit | |||
breakers to perform their function under design basis conditions and from the time the circuit | |||
breakers were recognized to be different, TVA has not performed an equivalency evaluation | |||
of the modified commercial grade circuit breakers in relation to adequacy or performance. | |||
TVA states that WCG-ACQ-1004 analyzed the effects that were introduced by the new | |||
modification to the circuit breaker but WCG-ACQ-1004 section 7, computation and analysis, | |||
only states that the circuit breakers depth changed by 1/4 inch and that the model number | |||
remained the same. TVA, on that basis, deemed the changes to be minor and thus the new | |||
circuit breaker was seismically qualified under like-for-like conditions to the prior circuit | |||
breakers. The 120VAC Vital Instrument Power Boards require the dimension that changed | |||
as the critical dimension necessary to adequately seat the circuit breakers into the clamping | |||
arrangement for design basis conditions. Calculation WCG-ACQ-1004 does not evaluate | |||
the design basis performance of the new circuit breaker with the changes and new | |||
modifications but rather evaluates the structural failure characteristics of the new Micarta | |||
plate, the bolts used to attach it, and the power board floor anchor bolts each as separate | |||
components of the power boards. In addition, TVA has not presented any evidence of the | |||
dimensional comparison between the back of the front cover plate and the front of the angle | |||
iron to the circuit breakers dimensional critical characteristic and how it is maintained during | |||
design basis conditions. The depth dimension is critical and must be maintained across the | |||
width and height of the clamping arrangement over time so that all of the 12 circuit breakers | |||
across the front cover plate are completely secured. | |||
Additionally, the staff has observed that some of the circuit breakers currently installed in the | |||
120VAC Vital Instrument Power Boards do not appear to be adequately seated into the | |||
power boards clamping arrangement. The staff provided this information and concerns on | |||
4 | |||
these circuit breakers to TVA. The staff has further observed that TVA does appear to have | |||
adequate quality controls to ensure the clamping arrangement is maintained or how the | |||
circuit breakers are replaced and adequately re-seated between the angle iron and the front | |||
panel cover, but appears to rely on skill of the craft. Furthermore, even though TVA asserts | |||
that the 1974 test seated the circuit breakers in the clamping arrangement and that they | |||
seemed to perform adequately, TVA has not yet evaluated any aging effects from the | |||
pressure the clamping arrangement provides over time. TVA has not evaluated if the | |||
clamping arrangement requires maintenance to maintain the critical dimension. The | |||
manufacturers design of the circuit breakers is to mount by four screws not by the pressure | |||
from the clamping arrangement, as evidenced by the four mounting tabs built into the circuit | |||
breakers, one at each corner. Because the body of the circuit breakers consists of two | |||
pieces of plastic held together by four small rivets and the plastic body secures and aligns | |||
the internal mechanisms of the circuit breaker, the pressure exerted over time may deform | |||
and degrade the alignment critical to their performance. The staff has determined that | |||
calculation WCG-ACQ-1004, as presented, is not an adequate evaluation of the new | |||
changes to the circuit breakers and does not analyze circuit breaker performance. | |||
NRC Conclusion | |||
On the basis of the foregoing, the NRC concludes that: (1) The as-constructed 120VAC Vital | |||
Instrument Power Board drawings for the 1974 seismic testing cannot be verified to match the | |||
as-constructed configuration of the TVAs current 120VAC Vital Instrument Power Boards. (2) | |||
IEEE 344-1975 stipulates that, the mounting of equipment to be tested shall be the same as that | |||
recommended for actual service and TVA incorrectly applied this standard. (3) The 120VAC | |||
Vital Instrument Power Boards are not confirmed to be rigid assemblies. (4) The newly acquired | |||
commercial grade circuit breakers were not adequately evaluated as like-for-like as replacement | |||
circuit breakers. The calculation WCG-ACQ-1004 is not an adequate equivalency evaluation. | |||
Therefore, the violation occurred as stated in the Notice. | |||
}} | }} |
Latest revision as of 08:41, 13 November 2019
ML102920665 | |
Person / Time | |
---|---|
Site: | Watts Bar |
Issue date: | 10/19/2010 |
From: | Ogle C NRC/RGN-II/DCI |
To: | Bhatnagar A Tennessee Valley Authority |
References | |
EA-10-195, IR-10-603 | |
Download: ML102920665 (8) | |
See also: IR 05000391/2010603
Text
UNITED STATES
NUCLEAR REGULATORY COMMISSION
REGION II
MARQUIS ONE TOWER
245 PEACH TREE CENTER AVENUE, NE
ATLANTA, GEORGIA 30303-1257
October 19, 2010
Tennessee Valley Authority
Mr. Ashok S. Bhatnagar
Senior Vice President
Nuclear Generation Development and Construction
Tennessee Valley Authority
6A Lookout Place
1101 Market Street
Chattanooga, TN 37402-2801
SUBJECT: RESPONSE TO DISPUTED NOTICE OF VIOLATION (NOV)05000391/2010603-08
Dear Mr. Bhatnagar:
Thank you for the TVA letter dated September 7, 2010, in response to our NOV
05000391/2010603-08 dated August 5, 2010. The Notice described a violation that was
identified during an inspection conducted by the Nuclear Regulatory Commissions (NRCs)
Division of Construction Inspection (DCI).
In the response, TVA disputed NOV 05000391/2010603-08. As base for its denial TVA
indicated the following:
- Westinghouse seismically tested the120VAC Vital Instrument Power Board assembly in
1974 in a configuration which duplicated the actual configuration in the plant.
- Commercial grade replacement breakers were dedicated in 1992 using the guidance of
IEEE 344-1975 Section 6.4, Device Testing.
- The calculated natural frequencies of the front cover panel show it to be rigid. The rigid
clamping arrangement of rear retaining angles and front cover panel do not introduce any
additional flexibility that would require replication of the 1974 testing. The 1974 and 1992
tests demonstrate the original board and breakers remain seismically qualified.
- Subsequent modification to the commercial grade circuit breakers in 2008 were evaluated
as like-for-like and the breakers remained seismically qualified. Calculation WCG-ACQ-
1004 analyzed the effects that were introduced by the modification, demonstrated an
adequate review for suitability of application, and analyzed the impact on other components.
After review and consideration of TVAs response, the NRC has concluded that, for the reasons
given in the enclosure to this letter, the violation occurred as stated in NOV 05000391/2010603-
08. The violation involves the failure to accomplish activities affecting quality in accordance with
10 CFR 50 Appendix B. You are required to provide an additional response in accordance with
10 CFR 2.201. The violation was categorized at Severity Level IV and will remain open until the
NRC has verified implementation of TVAs corrective actions during a subsequent inspection.
A. Bhatnagar 2
In accordance with 10 CFR 2.390 of the NRCs Rules of Practice, a copy of this letter and its
enclosure will be available electronically for public inspection in the NRC Public Document
Room or from the Publicly Available Records (PARS) component of the NRCs document
system (ADAMS). Adams is accessible from the NRC Web site at http://www.nrc.gov/reading-
rm/adams.html (the Public Electronic Reading Room).
If you have any questions regarding this correspondence, please contact Mark Lesser at
404-997-4460.
Sincerely,
/RA/
Charles Ogle, Director
Division of Construction Inspection
Docket Nos.: 50-392
License Nos.: CPPR-92
Enclosure: NRC Evaluation and Conclusion
ML102920665 XG SUNSI REVIEW COMPLETE
OFFICE RII:DCI RII:DCI RII:EICS OE NRR RII RII
SIGNATURE MSL CRO CFE e-mail e-mail TNF GC
NAME M. Lesser C. Ogle C. Evans G. Gulla K. Manoly T. Fanelli G. Crespo
DATE 10/6/10 10/19/10 10/6/10 10/8/10 10/6/10 9/29/10 9/28/10
E-MAIL COPY? YES NO YES NO YES NO YES NO YES NO YES NO YES NO
A. Bhatnagar 3
cc w/encl:
Mr. Gordon P. Arent Mr. M.J. Hellstern
Manager General Manager
New Generation Licensing NGDC Governance & Oversight
Nuclear Generation Development Tennessee Valley Authority
and Construction 3A Blue Ridge Place
WBN Nuclear Plant 1101 Market Street
P.O. Box 2000 Chattanooga, Tennessee 37402-2801
Spring City, Tennessee 37381
Mr. R.M Krich
Mr. Masoud Bajestani Vice President
Vice President Nuclear Licensing
WBN Unit Two Tennessee Valley Authority
WBN Nuclear Plant 3R Lookout Place
Tennessee Valley Authority 1101 Market Street
P.O. Box 2000 Chattanooga, Tennessee 37402-2801
Spring City, Tennessee 37381
Mr. E.J. Vigluicci
Mr. Michael K. Brandon, Manager Assistant General Counsel
Licensing and Industry Affairs Tennessee Valley Authority
WBN Nuclear Plant 6A West Tower
Tennessee Valley Authority 400 West Summit Hill Drive
P.O. Box 2000 Knoxville, Tennessee 37402
Spring City, Tennessee 37381
Lawrence E. Nanney, Director
Mr. Preston D. Swafford Tennessee Department of Environmental
Chief Nuclear Officer Health and Conservation
and Executive Vice President Division of Radiological Health
Tennessee Valley Authority 3rd Floor, L&C Annex
3R Lookout Place 401 Church Street
1101 Market Place Nashville, TN 37243-1532
Chattanooga, Tennessee 37402-2801
Mr. D. E. Grissette
County Executive Site Vice President
375 Church Street WBN Nuclear Plant
Suite 215 Tennessee Valley Authority
Dayton, Tennessee 37321 P.O. Box 2000
Spring City, Tennessee 37381
W.R. Crouch, Manager
WBN Unit 2 Licensing County Mayor
Watts Bar Nuclear Plant P.O. Box 156
Tennessee Valley Authority Decatur, Tennessee 37322
P.O. Box 2000
Spring City, Tennessee 37381 Senior Resident Inspector
WBN Nuclear Plant
Mr. Gregory A. Boerschig U.S. NRC
Plant Manager, WBN Nuclear Plant 1260 Nuclear Plant Road
Tennessee Valley Authority Spring City, Tennessee 37381-2000
P.O. Box 2000
Spring City, Tennessee 37381
A. Bhatnagar 4
Letter to Ashok S. Bhatnagar from Charles R. Ogle dated October 19, 2010
SUBJECT: RESPONSE TO DISPUTED NOTICE OF VIOLATION (NOV)05000391/2010603-08
Distribution w/encl:
L. Raghavan, NRR
S. Campbell, NRR
P. Milano, NRR
C. Evans, RII
L. Douglas, RII EICS
R. Haag, RII, DCP
W. Bearden, RII, WBN Unit 2 SRI
E. Guthrie, RII DRP
OE Mail (OEMAIL)
PUBLIC
cc email distribution w/encl:
Greg Scott
Tennessee Valley Authority
Electronic Mail Distribution
NRC EVALUATION AND CONCLUSION
The violation was identified during an inspection conducted by the Nuclear Regulatory
Commissions (NRC) Division of Construction Inspection (DCI) at Watts Bar Nuclear Station
Unit 2 in Spring City Tennessee. TVA disagreed with the violation by letter dated
September 7, 2010, and provided the following bases:
- Westinghouse seismically tested the120VAC Vital Instrument Power Board assembly in
1974 in a configuration which duplicated the actual configuration in the plant.
- Commercial grade replacement breakers were dedicated in 1992 using the guidance of
IEEE 344-1975 Section 6.4, Device Testing.
- The calculated natural frequencies of the front cover panel show it to be rigid. The rigid
clamping arrangement of rear retaining angles and front cover panel do not introduce any
additional flexibility that would require replication of the 1974 testing. The 1974 and 1992
tests demonstrate the original board and breakers remain seismically qualified.
- Subsequent modification to the commercial grade circuit breakers in 2008 were evaluated
as like-for-like and the breakers remained seismically qualified. Calculation WCG-ACQ-
1004 analyzed the effects that were introduced by the modification, demonstrated an
adequate review for suitability of application, and analyzed the impact on other components.
A. Specific Bases for Disputing NOV 05000391/2010603-08
In its letter of September 7, 2010, TVA disagreed with the NRCs conclusion regarding the 1992
qualification of circuit breakers and subsequent deficient equivalency evaluation at Watts Bar
Unit 2.
TVA cited the following as bases for disputing the NRCs conclusion that a violation occurred:
1. Westinghouse seismically tested the 120VAC Vital Instrument Power Board assembly with
Heinemann Model CF2-Z51-1 circuit breakers in 1974, mounted in place solely by clamping
pressure applied by the front cover pushing twelve breakers against the rear angle supports.
There were no additional screws to secure the breaker to the frame. This configuration
duplicated the actual configuration in the plant.
2. Commercial grade replacement breakers were dedicated in 1992 by attaching an individual
breaker to the vibratory source with bolting. IEEE 344-1975 section 6.4, Device Testing,
allows a device, intended to be mounted on a panel, to be mounted directly to the shake
table if the in-service excitation can be simulated. A 3g input motion (which exceeded the
2.72g highest measured acceleration [seismic demand] in the 1974 test) was applied.
3. The retention of breakers in the as-constructed board assembly is by a clamping
arrangement provided by two rear retaining angle iron members and the front cover panel.
The calculated natural frequencies of the front cover panel in the three directions were in
excess of 33 Hz and rigid. The rigid clamping arrangement of rear retaining angles and the
front cover panel do not introduce any additional flexibility that would require replication of
the 1974 testing. The 1974 and 1992 tests demonstrate the original board and breakers
remain seismically qualified.
4. Subsequent modification to the new breakers in 2008 added a Micarta plate and bolts to
attach it. Calculation WCG-ACQ-1004 addressed the qualification of the circuit breakers
with the Micarta plate and concluded that the component (i.e., circuit breaker) remained
seismically qualified under like-for-like conditions per the 1992 seismic qualification device
2
test. Calculation WCG-ACQ-1004 analyzed the effects that were introduced by the
modification, demonstrated an adequate review for suitability of application, and analyzed
the impact on other components.
B. NRC Evaluation of Licensees Response
The NRC carefully reviewed TVAs response and concludes that the violation occurred as
stated in the Notice of Violation. The bases for this determination are as follows:
1. The staff was unable to substantiate TVAs assertion that the 1974 test replicated the
mounting configuration in the plant. The staffs review of the 1974 test records and
configuration drawings revealed conflicting and inconsistent information. TVA cites the 1974
Westinghouse qualification and it references Westinghouse drawings CO-33419-MKE-M2
and M3 for the as-constructed configuration of the 120VAC Vital Instrument Power Board
assembly. The Westinghouse drawings are inconclusive in determining if fasteners secured
the circuit breakers and incorrectly show the orientation of the angle iron supports and the
profile of the front cover plate. TVA drawing 45N7OI-4 R2 also depicts the as-constructed
Watts Bar configuration of the 120VAC Vital Instrument Power Board assembly. The
method of securing the circuit breakers, angle iron supports for the back of the breakers,
and the profile for the front cover plates shown in the two sets of drawings are different.
Drawing 45N7OI-4 R2 shows fasteners (screws or bolts) securing the circuit breakers to the
rear angle iron supports, which are not in the as-constructed configuration, but accurately
shows the orientation of the angle iron supports and the profile of the front cover plates that
clamp the circuit breakers against the angle iron supports. Additionally the inside face of the
front cover plate of the existing Watts Bar power boards has stiffening supports both
vertically and horizontally on each panel. Neither the Westinghouse nor the TVA drawings
show these supports in the drawings. TVA has not reconciled these differences. The staff
was unable to verify that the existing Watts Bar 120VAC Vital Instrument Power Board
assembly configuration is the same as the 1974 qualification test configuration.
2. IEEE-344-1975, for the commercial grade dedication testing, Section 6.1.1, Mounting, states
in part, for the equipment to be tested, the mounting method shall be the same as that
recommended for actual service. TVA incorrectly cites IEEE 344-1975; Section 6.4 which
allows components mounted on a panel or plate, i.e. flat surfaces, (flat doors, flat top, flat
back, or flat sides), without any other interposing parts that could interfere with those parts
to be mounted directly to a seismic test table fixture. Mounting such components to a test
table on a simulated flat plate instead of the actual panel, in that case, would adequately
simulate the mounting of those types of components. The applicant described the in-service
mounting in their response as a 36 front panel with two horizontal angle iron supports in the
rear and that the breakers were held in place solely by the clamping pressure applied by the
front cover pushing the twelve breakers against the rear angle supports. The circuit
breakers described by the applicant do not represent components mounted on a panel that
can be tested in accordance with Section 6.4 of IEEE-344. Furthermore, the 1992
qualification report specified that it applies only to circuit breakers being secured by
fasteners. The 1992 qualification report for the circuit breakers stated that they were
mounted for testing with screws, to a test table plate, in a manner that simulates the normal
in-plant mounting. The TVA drawing 45N7OI-4 R2 with the error depicting fasteners was
created in the 1970s and was available for the 1992 qualification personnel. TVA has not
adequately resolved these inconsistencies.
3
3. TVA did not support their assertion that the front cover panel is rigid and that the clamping
arrangement of rear retaining angles in combination with the front cover panel are rigid.
TVA in its response letter stated, The calculated natural frequencies of the front cover panel
in the three directions were also in excess of 33 Hz and rigid. When asked to produce the
calculation for examination, TVA stated that the calculation was informal and not retained
and therefore could not be presented for examination. Furthermore, according to drawings
CO-33419-MKE-M2 & M3 the 120VAC Vital Instrument Power Boards construction consists
of panels and angle iron supports that are bolted together. The front cover panels are
bolted through threads in the steel angle iron. IEEE 344-1987 clarifies that, such cabinets
with bolted doors or panels, produce impacts, rattling, chatter, or banging and these impacts
are transmitted throughout the equipment and result in increased acceleration levels at
frequencies much higher than the original frequencies imposed by the shake table. A low
frequency input thereby produces high-frequency responses that may adversely affect
devices mounted in the equipment and must be considered in their qualification. Therefore,
an engineering analysis was necessary to ascertain the adequacy of the power boards and
circuit breakers; however, TVA did not perform an engineering analysis nor provide an
adequate basis that supports a conclusion that the panel arrangement is rigid and not
flexible.
4. TVA did not perform an adequate evaluation to support a conclusion that the 2008
modification of the newest circuit breakers are like-for-like replacements to those circuit
breakers tested in 1974 or 1992. The new circuit breakers were determined by TVA, on or
before July 2008, to be different in dimension from the circuit breakers dedicated in 1974 or
1992 in that they no longer fit into the 120VAC Vital Instrument Power Boards by the
clamping arrangement and had to be modified to fit. Since the new circuit breakers are field
modified with the Micarta plate to fit into the 120VAC Vital Instrument Power Boards, the
new circuit breakers are not like-for-like to the prior circuit breakers. Before September 7,
2010 TVA had never determined the critical characteristics necessary to enable the circuit
breakers to perform their function under design basis conditions and from the time the circuit
breakers were recognized to be different, TVA has not performed an equivalency evaluation
of the modified commercial grade circuit breakers in relation to adequacy or performance.
TVA states that WCG-ACQ-1004 analyzed the effects that were introduced by the new
modification to the circuit breaker but WCG-ACQ-1004 section 7, computation and analysis,
only states that the circuit breakers depth changed by 1/4 inch and that the model number
remained the same. TVA, on that basis, deemed the changes to be minor and thus the new
circuit breaker was seismically qualified under like-for-like conditions to the prior circuit
breakers. The 120VAC Vital Instrument Power Boards require the dimension that changed
as the critical dimension necessary to adequately seat the circuit breakers into the clamping
arrangement for design basis conditions. Calculation WCG-ACQ-1004 does not evaluate
the design basis performance of the new circuit breaker with the changes and new
modifications but rather evaluates the structural failure characteristics of the new Micarta
plate, the bolts used to attach it, and the power board floor anchor bolts each as separate
components of the power boards. In addition, TVA has not presented any evidence of the
dimensional comparison between the back of the front cover plate and the front of the angle
iron to the circuit breakers dimensional critical characteristic and how it is maintained during
design basis conditions. The depth dimension is critical and must be maintained across the
width and height of the clamping arrangement over time so that all of the 12 circuit breakers
across the front cover plate are completely secured.
Additionally, the staff has observed that some of the circuit breakers currently installed in the
120VAC Vital Instrument Power Boards do not appear to be adequately seated into the
power boards clamping arrangement. The staff provided this information and concerns on
4
these circuit breakers to TVA. The staff has further observed that TVA does appear to have
adequate quality controls to ensure the clamping arrangement is maintained or how the
circuit breakers are replaced and adequately re-seated between the angle iron and the front
panel cover, but appears to rely on skill of the craft. Furthermore, even though TVA asserts
that the 1974 test seated the circuit breakers in the clamping arrangement and that they
seemed to perform adequately, TVA has not yet evaluated any aging effects from the
pressure the clamping arrangement provides over time. TVA has not evaluated if the
clamping arrangement requires maintenance to maintain the critical dimension. The
manufacturers design of the circuit breakers is to mount by four screws not by the pressure
from the clamping arrangement, as evidenced by the four mounting tabs built into the circuit
breakers, one at each corner. Because the body of the circuit breakers consists of two
pieces of plastic held together by four small rivets and the plastic body secures and aligns
the internal mechanisms of the circuit breaker, the pressure exerted over time may deform
and degrade the alignment critical to their performance. The staff has determined that
calculation WCG-ACQ-1004, as presented, is not an adequate evaluation of the new
changes to the circuit breakers and does not analyze circuit breaker performance.
NRC Conclusion
On the basis of the foregoing, the NRC concludes that: (1) The as-constructed 120VAC Vital
Instrument Power Board drawings for the 1974 seismic testing cannot be verified to match the
as-constructed configuration of the TVAs current 120VAC Vital Instrument Power Boards. (2)
IEEE 344-1975 stipulates that, the mounting of equipment to be tested shall be the same as that
recommended for actual service and TVA incorrectly applied this standard. (3) The 120VAC
Vital Instrument Power Boards are not confirmed to be rigid assemblies. (4) The newly acquired
commercial grade circuit breakers were not adequately evaluated as like-for-like as replacement
circuit breakers. The calculation WCG-ACQ-1004 is not an adequate equivalency evaluation.
Therefore, the violation occurred as stated in the Notice.