B11756, Forwards Seismic Interaction Review Program... & Application of Data to Seismic Interaction..., in Response to NRC .List of non-Seismic Category I Equipment Installed in Seismic Category I Areas Also Encl
| ML20133F779 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 09/27/1985 |
| From: | Opeka J NORTHEAST NUCLEAR ENERGY CO., NORTHEAST UTILITIES |
| To: | Youngblood B Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20133F781 | List: |
| References | |
| B11756, NUDOCS 8510110226 | |
| Download: ML20133F779 (6) | |
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.a e.ccco September 27,1985 Docket No. 50-423 Bil756 Director of Nuclear Reactor Regulation Mr. B. J. Youngblood, Chief Licensing Branch No. I Division of Licensing U. S. Nuclear Regulatory Commission Washington, D. C. 20555
References:
(1) 3.
F. Opeka to B. J. Youngblood, " Seismic Interaction Program," dated August 8,1985.
(2)
B. J. Youngblood to J. F. Opeka, " Request for Additional Information," dated September 17,1985.
Gentlemen:
Millstone Nuclear Power Station, Unit No. 3 Seismic Interaction Program Representatives from Northeast Nuclear Energy Company (NNECO), Stone &
Webster, and EQE Incorporated met with the NRC Staff on June 21,1935 to present the seismic interaction program for Millstone Unit No. 3. The program presented at the meeting by NNECO addresses the seismic interaction between both non-seismic Category I equipment to seismic Category I and seismic Category I to scismic Category I equipment.
Regulatory Guide 1,29 and Standard Review Plan (SRP) 3.9.2 outline the requirement for non-seismic equipment in the vicinity of seismic equipment. Most Near Term Operating License applicants (NTOLs) have chosen to design and install non-seismic Category I equipment supports in the vicinity of seismic Category I equipment to seismic criteria. Millstone Unit No. 3 has utilized this standard approach in many instances, with several of these outlined in Attachment 3. Additionally,in many instances another method utilized to implement the NRC criteria is by verifying that non-seismic Category I equipment will not adversely interact with scismic Category I equipment based upon a historical data base of equipment subjected to large motion carthquakes.
In Reference (1), NNECO provided the Staff information regarding the seismic interaction program for Millstone Unit No. 3.
In Reference (2), the Staff requested additional information regarding the utilization of historical earthquake data in the evaluation of non-seismic Category I piping systems. In a subsequent telecon concerning Reference (2) the Staff specifically requested that NNECO demonstrate quantitatively that the database of historical earthquake information is directly applicabic to the seismic interaction program.
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A copy of " Seismic Interaction Review Program, Millstone Unit No. 3, Nuclear Power Station" is included as Attachment 1. is an EQE report entitled "The Application of Experience Data to the Seismic Interaction Study at the Millstone Unit No. 3 Nuclear Power Plant."
L Since all seismic Category I equipment is located in scismic Category I buildings, this program is limited to potential Interactions between non-seismic Category I equipment and seismic Category I equipment located in seismic Category I buildings.
Further, an extensive amount of non-safety related equipment in seismic areas was designed seismically (see Attachment 3 for detailed list). All of this equipment is adequately supported and does not rely on database information for assurance of structural integrity.
This may represent a significant reduction in what the Staff perceives the scope of the program to be.
Attachment I defines the equipment which does rely on the database for demonstrating structural integrity.
Primary amongst these is non-seismic Category I piping, it should be emphasized that the database is utilized only to demonstrate gross structuralintegrity and to estimate the severity and predicted interactions.
Interactions due to the seismic displacement of non-seismic equipment are identified by the same method as would have been employed had structural integrity been demonstrated by classical analyses.
Specifically interactions are identified by walkdowns and evaluated on a case by case basis.
Non-schmic Category I piping will not become a gravity missile (fall down) if the structural integrity of the piping and supports can be demonstrated.
The database includes piping systems installed in plants which have experienced carthquakes well beyond the Millstone Unit No. 3 design basis.
Similarity between database equipment and Millstone Unit No. 3 equipment is established both by direct comparison and by assessment of design standards and codes.
Comparison criteria for piping include:
Piping Parameters Pipe size Pipe material Pipe components Pipe design and fabrication System operating conditions Pipe Support Parameters Pipe Support spacing Support function (type of support provided)
Support design and fabrication Component standard support hardware (Seismic Category i Items)
Seismic Parameters Site peak ground acceleration Building floor response spectra Differential displacements between floors Building fundamental frequencies Similar criteria is utilized in treating other type of equipment using the database.
. A detailed list including the r.inge of these parameters is being prepared for explicit comparison to the database. Outliers to the database are identified during implementation of the program if they are important from an interaction standpoint. The non-seismic Category I equipment listed in Attachment I at Millstone Unit No. 3 and the database equipment were designed with no special consideration of seismically induced loads. Consequently,if sufficient similarity can be shown for the above parameters taken individually and in combination, then the Millstone Unit No. 3 piping will maintain structural integrity if subjected to the design earthquake. Establishing the similarity is a fundamental function of this program.
The seismic interaction program is implemented by means of walkdowns by trained reviewers. These walkdowns are essentialin that they:
o Verify that the non-seismic Category I systems or portions of non-seismic Category I systems which have the potential of interacting with seismic Category I equipment are enveloped by the data base and, therefore, will not fait catastrophically.
o identify displacement induced interactions with active seismic Category I equipment. When found, these interactions are prevented.
o identify displacement induced interactions with passive seismic Category I equipment. The severity of the interaction is evaluated and the situation is corrected as appropriate.
All walkdowns are verified by an independent reviewer.
The database, coupled with site walkdowns, assures that non-seismic Category I systems which could interact with seismic Category I equipment maintain structural integrity and that their seismic displacements do not cause unacceptable interactions.
This progt am applies only to structural interaction between equipment.
Concerns regarding equipment wetting, flooding, high energy line break and jet impingement are not covered in this program. These issues are completely addressed in Millstone Unit No. 3 FSAR Section 3.6.
This program would allow enhanced maintenance and improved in-service inspection access (less interference) resulting in lower radiation exposure over the life of the plant. In summary, NNECO considers the program will result in schedular and economic benefits without impacting the safety of the plant.
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We trust this information is appropriate to address the Staff's concerns. The results of the detailed parameter comparison will be provided for the Staff's review as it becomes available.
Very truly yours, NORTHEAST NUCLEAR ENERGY COMPANY et. al.
BY NORTHEAST NUCLEAR ENERGY COMPANY Their Agent he r1A.
J. F. O elbd U
Senior Vice President STATE OF CONNECTICUT )
) ss. Ber!!n COUNTY OF HARTFORD
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Then personally appeared before me J. F. Opeka, who being duly sworn, did state that he is Senior Vice President of Northeast Nuclear Energy Company, an Applicant herein, that he is authorized to execute and file the foregoing information in the name and on behalf of the Applicants herein and that the statements contained in said information are true and correct to the best of his knowledge and belief.
Ohhnletb X/t Notary Puby jy Commission f.xpires March 31,1983 l
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E The following is a list of non-seismic Category I equipment installed in seismic Category I areas which were designed scismically. This list is not complete but illustrates the extent to which non-seismic Category I equipment has been seismically designed or analyzed, o
Non-seismic Category I cable trays and conduits are supported seismically in most areas of seismic Category I buildings, Non-seismic Category I ductwork located in seismic Category I buildings is o
seismically designed and supported.
MCCs near safety related equipment are located to preclude contact and '
o are seismically supported, o
Panels in the control room are designed and installed to prevent interaction with safety related equipment, o
items such as CRTs in the main boards, control room lights and ceiling panels are scismically supported.
o in general non-seismic Category I electrical equipment is supported on embedded sills in a fashion similar to seismic Category I equipment or, in the case of wall mounted equipment, on standard support elements similar to scismic Category I equipment.
o Mechanical equipment is typically supported with cast in place anchors.
o Space heaters in seismic Category I areas are supported scismically.
There are numerous equipment items which are required by specification and which have been verified by as-built review to be seismically designed. No equipment whether scismic Category I or non-seismic Category I is exempt from the interaction review program. This means that even seismic Category I to seismic Category 1 interactions will be identified.
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