ML19221B054
| ML19221B054 | |
| Person / Time | |
|---|---|
| Issue date: | 03/31/1979 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| References | |
| NUREG-75-087, NUREG-75-087-03.10, NUREG-75-87, NUREG-75-87-3.10, SRP-03.10, SRP-3.10, NUDOCS 7907120322 | |
| Download: ML19221B054 (8) | |
Text
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Wh STANDARD REVIEW PLAN
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OFFICE OF NUCLEAR REACTOR REGULATION SECTI0d 3 10 SEISMIC QUALIFICATION OF CATEGORY I INSTRUMENTATION AND ELECTRICAL EQUIPMENT REVIEW RESPONSIBILITIES Primary - Mechanical Engineering Branch (MEB)
Secondary - Instrumen'.ation and Control Systems Branch (ICSB)
Power Systems Branch (PSB)
I.
ARfAS OF REVIEW Information concerning the methods of test and analysis employed to assure the oper-ability of essential instrumen;ation and electrical equipment in the event of an earth-quake should be provided in the applicant's safety analysis report (SAR) and is reviewed by the MEB to assure conformance with the requirements of General Design Criterion 2.
Systems and components that must retain structural integrity, remain leaktight, or continue to function in the event of an earthquake, in order to assure safe operation or shutdown of the plant, must be designed to sei nic Category I requirements.
At the construction permit (CP) stage, the staff review covers the following specific areas 1.
The criteria for seismic qualification, such as the deciding factor., for choosing between tests or analyses, the considerations in defining the seismic input motion, and the demonstration of adequacy of the seismic qualification program.
2.
The methods and proc;dures, inclellq tests and analyses, used to asst.re t'le opf ra-bility of seismic Category I instruneatation and electrical equipment in the evont of a safe shutdown earthquake (SSE, and to assure structural integrity and oper-ability of the equipment after occurrenca of the operating basis earthqurke (OBE).
Instrumentation and electrical equipment that must be designed to seismic Category I requirements include the reactor protection system, engineered safety feature circuits, emergency power systeis, and all auxiliary safety-related elec-trical systems.
3.
The methods and procedures of analysis or testing of the supports for the seismic l
Category I instrumentation and electrical equipment, and the procedures used to USNRC STANDARD REVIEW PLAN
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account for possible amplification of v bratory motion (amplitude and frequency i
content) under seismic conditions. Supports include items such as battery racks, instrument racks, :ontrol consoles, cabinets, panels, and cable trays.
At the operating license (OL) stage, the staff reviews the results of tests and analyses to assure the proper implementation of criteria established in the CP review, and to l
demonstrate adequate seismic qualification.
The ICSB and PSB verify that all of the seismic Category I instrumentation, controlc and l electrical equipment and supports are included in the seismic qualification program, that the electrical performance aspects of these items are included in the seismic qualification testing, anc that the equipmert mount:ng during the test adequately sim-ulates tha actual service mounting. For these cc.ididerations, ICSB has responsibility for instrumentation and control systems while PSB has respcnsibility for electrical power systems.
II.
ACM PTANCE CRITERIA The acceptance criteria for the areas of reviaw designated in subsert;on 1 are as follows.
Conformance with these criteria satisfies the w cable portions of General Design Criterion 2.
1.
For plants for which the CP application, including the preliminary safety anaiysis report (PSAR), was docketed before October 27, 1972, the seismic ',ualification of Category I instrumentation, electrical equin.., anu wpper, sheuld meet the requirements of IEEE Std. 344-i971 (Ref. 3).
For these plants an additional staff review will be conducted to assure that such comaonents do have adequate margin to perform their intended d? sign functions during the seismic event.
Special emphasis should be placed on the effects of possible multi-mode response and simultaneous vertical anci horizontal excitations nn the component operability. The following requirements should be met:
a.
Seismic Qualification for Equipment Operability (1) Tests or analyses are required to confirm the operability of all Jeismic Category I electrical equipment and instrumentation during and after an earthquake of magnitude up to and including the SSE. (The analysis method is not recommended for ccrplex equipment that cannot be modeled accurately enough to predict its response correctly for functional verifi-cation.) The secondary reviewer; verify the completeness of the seismic qualification program based upon the acceptance criteria given in the SRP sections fo' which they have primary responsibility.
Designs and equipment that have been previously qualified by means of testsandan%ypesequivalenttothosedescribedheremaybeacceptable l
provided that proper dgcumen'ition of such tests and analyses is submitted.
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(2) Single frequency input excitations, such as continuous single frequency sinusoidal motions or sine beat motions, may be used; however, multi-9..
frequency input excitations as delineated in IEEE Std. 344-1975 (Ref. 4) are preferable and should be utilized whenever possiblc. In either case, the maximum input motion acceleration should equal or e;.ceed the maximum seismic acceleration expected at the equipment mou" ting location. See subsection II.l.b(3) below for a discussion of the participation of the equipment supports.
(3) For single frequency input excitation, the discrete frequencies at which the test input motion is applied should cover the range 1-33 Hz If resonant frequencies of the equipment and equipment suppoits are iden-tified by prior analysis or " sweep" testing or both, tests conducted only at the resonant frequencies are acceptable. However, if multi-frequency input excitations are used, the level of response spectrum derived from the test inpi.t should envelope the corresponding response spectrum level required for seismic qualification at the component mounting location.
(4) Equiprent should be tested in the operational condition. Procedures for monitoring the equipment under test and the acceptability of the signals so obtainec for functional verification are reviewed by ICSB and PSB in accordance with acceptance criteria given in the SRP sections for which they have primary responsibility.
(5) The test motion may be applied to one vertical and two orthugonal hori-zontal axes separately. However, biaxial input with simultaneous vertical and horiznntal excitationc as delineated in IEEE Std. 344-1975 is prefer-able and J._uld be utilized whenever possible.
(6) The test program may be based upon selectively testing a representative number of mechanical components according to type, load level, size, etc.
on a prototype basis.
b.
Seismic Design Adequacy of Supports (1) Analyses or tests should be performed for all supports of seismic Category I electrical equipment and instrumentation to assure tieir structural capability to withstand seismic excitation.
(2) Tho analytical results should include the maximum accelerations and associated frequencies at the equipment mounting location, and the com-bined stresses of the support structures should be within the limits of the ASME Code,Section III, Subsection NF, " Component Support Structures" (Ref. 2) or other appropriate limits which are acceptable to the staff.
(3) Supports should t>e tested with equipment installed or with a dummy simulat-ing the equivalent inertial mass effects and dynamic coupling to the support. If the equipment is installed in a nonoperational mode for the support test, the response at the equipment mounting location should be monitored such that the maximum accelerations and associated frequencies can be defined. In such a case, equipment should be tested separately for operability and the actual input motion to the equipment should be 9
more conservative in amplitude and frequency content than the monitored response.
146 328 3.10-3 D*I
(4) The requirements of subsection II. l.a(2), (3), and (5), above, are applic-l able when tests are conducted on the equip.1ent supports.
2.
fur plants for which the CP application was docketed af ter October 27, 1972, the seismic qualification of Category I instrumer,totion, electrical eqbipment, and supports should meet the requiremerits of IEEE Std. 344-1975 and Regulatory Guide 1.100, and special emphasis should be placed on the follcwfrrg (also see Refs. 4 a.1d 6):
a.
Seismic Qualification for Equipment Operability (1) Tests and analyses are required to confirm the operability of all seismic l Category I electrical equipment and instrumentation during and after an earthquake of magnitude up to and including the OBE and SSE. Prior to SSE qualification, it should be demonstrated that the equipment can withstand the OBE excitation without loss of structural integrity.
Analyses alone, without tes, ting, are acceptable as a basis for seismic qualification only if the necessary functinnal operability of the instru-mentation or equipment is assured by its structural integrity alone.
When complete seismic testing is impractical, a combination of tests and analyses is acceptcble. The secondary reviewers verify the completeness of the seismic qualification program based upon the acceptance criteri given in the SRP sections for which they have primary resporisibility.
Designs and equipment that t. ave been previously qualified by means of tests and analyses equivalent to those described here are acceptable provided that proper documentation of such tests and analyses is submitted.
(2) The characteristics of the required seismic input motion should be specified by respcnse spectrum or t: se history methods. These characteristics, derived from the structures or systems seismic analysis, should be represen-tative of the seismic input motion at the equipment mounting locations.
(3) Equipment should be tested in the operational condition. Operability should be verified dur ing and af ter the testing.
(4) The actual test input motion should be characterized in the same manner as the requiret input mot.on, and the conservatism in amplitude and frequency content should be demonstrated (i.a, the test response spectrum (TRS) should envelope the required response spectrum (RRS) over the critical frequency range).
(5) Seismic excitation generally has a br6ad frequency content. Multi-frequency l vibration input r,otion should be ur.ed.
However, single frequency input motion, such as sine baats, is acceptable provided the characteristics of the required input motion indicate that the motion is dominated by one frequency (e.g., by structural filtering effects), the anticipated response of the equipment is adequately represented by one mode, or the input has sufficient intensity and duration to excite all irides simultaneously to l
the required amplitudes such that the test response spectra will envelope the correspondino required response spectra over the frequency range covering all the individual modes.
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Components that have been previously tested to IEEE Std. 344-1971 should be requalified using multi-frequency test input motion unless justifica-tion for using a single frequency test is provided.
(6) The test input motion should be applied to one vertical axis and one principal horizontal axis (or two orthogonal horizontal axes) simul-taneously unless it can be demonstrated that the equipment response in the vertical direction is not sensitive to the vibratory motion in the horizontal direction, and vice versa.
The time phr
- of the inputs in the vertical and horizontal directions must be suct it a purely recti-linear resultant input is avoided. An acceptable alternative is to test with vertical and horizontal inputs in phase, and then repeat the test with inputs 180 degru out of phase.
In addition, the test must be repeated with the equipment rotated 90 degr&s horizontally.
Compcnents that have been previously testeo to IEEE Std. 344-1971 should be requalified using biaxial test input motions unless justification for using a sir.gle axis test input motion is provided.
(7) The fixture design should simulate the actual service mounting and should not cause any extraneous dynamic coupling to the test item.
(8) The in situ application of vibratory devices to superimpose the seismic vibratory motions on a complex active device for operability testing is acceptable when it is shown that a meaningful test can be made in this way.
9 (9) The test program may be based upon selectively testing a representative number of components according to type, load level, size, etc., on a prototype basis.
b.
Seismic Design Adequacy of Supports (1) Analyses or tests should be performed for all supports of seismic ategory I electrical equipment and instrumentation to assure their structural capability to withstand <;smic excitation.
(2) The analytical results should include the required input motions to the mounted equipment as obtained and characterized in the manner stated in subsection ll.2.a(2), above, and the combined stresses of the support l
structures should be within the limits of the ASME Code,Section III.
Subsection NF, " Component Support Structures" (Ref. 2) or other appro-priate limits which are acceptable to the staff. Refer to SRP Section 3.9.3.
(3) Suncorts sheuld be tested with equipment installed or with a dummy sim-ulating the equivalent equipment inertial mass effects and dynamic coupl-ing to the support. If the equipment 's installed in a nonoperational mode for the support test, the respnnse in the test at the equipment mounting location should be monitored and characterized in the manner as stated in subsection II.2.a(2), above.
In such a case, equipment should l
be tested separately for onerability and tne actual input motion to the
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equipment in this test should he more conservative in amplitude and frequency content than the monitored response from the support test 146 EO R"V-I 3.10-5
(4) The requirements of subsections ll.2.a(2), (4), (5), (6), and (7), above, are applicable when tests are conducted on the equipment supports.
c.
Verification That Seismic Qaalification Is Performed in the Proper Sequence of the Overall Qualification Program As defined in Part B of Regulatory Guide I.100 (reference 6',
IEEE Std 344-1975 (reference 4) is an ancilliary standard of IEEE Scd 323-1974 (endorsed with exceptions, by Regulatory Guide 1.89).
To assure that overall qualification has been performed r,roperly, the staf f review shall verify that the seismic testing portion has been performed in its proper sequence as indicated in Sections 5 and 6 of IEEE Std 323-1974. On request, ICSB will provide consultation on the acceptability of any qualification sequence not in compliance with IEEE 323e1974.
3.
In documenting the implementation of the seismic qualification program described above, the PSAR or FSAR should contain the following:
A detailed description of NSSS and A/F. practice followed in seismic qualifica-a.
tion, including criteria, methods and procedures used in conducting testing and analysis. (P3AR) b.
Information regarding administrative control of component seismic qualifica-tion, especially the handling of documentation, internal acceptance review prctedures, identification of the scope of NSSS and A/E suppliers, and inter-face problems among NSSS, A/E, equipment vendors and testing laboratories.
(PSAR) c.
A brief description of NSSS and A/E testing facilities, including the capa-bility of the facilities to test the functioning of the equipment being tested.
(PSAR) d.
Lists of equipment (devices or assemblies) and support structures shoJld be provided with the following information specified for each item: (FSAR)
(1) Description of equipment (i.e., manufacturer type, size, capacity) and/or supp'rt structure.
(2) Method of qualification useJ and reporting of results:
(a) Analysis or test It by analysis -
(i) describe whether static or dynamic analysis (ii) provide justification that the analysis assures the proper functioning of the equipment or support during the seismic event.
(iii) identify where the seismic qualification is implemented in the overall qualification program sequence.
If by testing-(i) describe whether single or multi-f requency test (ii) describe whether input w3s single or h haxial Rev. 1 3.10-6 146 331
(iii) identify test duration (iv) identify whether devices are mounted during the testing of assemblies or supporting structures (i.e., panels, racks, etc.)
9 and demonstrate the validity of any tests conducted without the devices (or suitable substitutes) or with the mounted devices in inoperative tondition.
(v) identify where the seismic testing is implemented in the over-al1 qualification program sequence.
(b) Report of the g-level required and tested to if using single fre-quency tests. Verify that the test response spectra (IRS) envelopes the required response spectra (RRS) if using multi-frequency tests.
(c) Report of the finding of resonance frequencies.
(d) Report or f unctional verification.
III. REVIEW PIOCEDURES The revi'wer will select and emphasize material from the procedures described below as may be appropriate for a particular case. Upon request from the primary reviewer, the secondcry review branches will prcvide input for the areas of review designa u d in subsection I.
The primary reviewer obtains and uses such input as necessary ti assure that.his review procedure is complete.
For ea h area of review the rollowing review procedures are used:
1.
At the CP stage, the staff reviews the pr; gram which the applicant has described in the PSAR for the seismic qualification of all Category I instrutrentition and elec-trical equipment. The program is measured against the requiremeats listed in subsection II.
Of particular interest are e proper use of test and analytical l
procedures. Equipment which is too complex for reliable mathematical modeling should be tested unless the ar.alytical procedures and corrtsponding design are convincingly conservative. Both the test and the analysis methods are reviewed for assurance that all important modes of response will be excited in tests or con-sidered in analysis. Proper consideration of
..ut motions so as to bound the required input, whether in terms of response spectra or time history in all neces-sary directions is verified. The use or treatment of supports is also reviewed.
2.
At the OL stage, the staff reviews the program again as described by the applicant in the FSAR. In addition, ti FSAR is reviewed for documentation of the successful implementation of the seismic qualification program including test and analysis esults. Also, the acceleration levels used in the tests and in the analyses are reviewed f or issurance that they equal or exceed the levels at the equioment mount-ing locations derived from structural response studies of the plant structure as built or as designed.
146 332 3.10-7 Rev. 1
IV.
EVALUATION FINDINGS 1he revievar should verify that suf ficient inf ormation has been provided and that the review supports conclusions of the following type Ifor a CP review), to be included in the staf f's safety evaluation report:
"The proper functioning of essential instrum"'.ation and electrical equipment ir>
the event of th.. safe shutdown earthquake (SSE) is necessary to initiate protective actions including, for example, operation of the reactor protection system, engi-neered safety features, and standby power systems.
"The seismic qualification program which will be implemented for seismic Category I instrumentation and electrical equipment provides adequate assurance that such equipment will function properly during the excitation from vibratory forces imposed by the safe shutuown earthquake and under the conditions of post ~ accident operation.
This program constitutes an acceptable basis for satisfying the applicable require-ments of General Design Criterion 2,"
At the OL stage, the review should provide justification for a finding similar to that above with the phrase "will be implemented" modified to read "has been implemented."
V.
REFERENCES 1.
10 CFR Part 50, Aupendix A, Genercl Design Criterion 2, " Design Bases for Protection Against Natural Phenomena."
2.
ASME Boiler and Pressure Vessel Code,Section III, " Nuclear Power Piant Ceirpo-nents," American Society of Mechanical Engineers.
3.
IEEE Std 341-1971, " Guide for Seismic Qualification of Class I Electric Equipment for Nuclear Power Generating Stations," Institute of Electrical and Electronics Engineers.
4.
IEEE Std 344-1975, " Recommended Practices for Seismic Qualification of Class lE l
Et,uipment for Nuclear Power Generating Stations," Institute of Electrical and Electronics Engineers.
5.
K. M. Skreiner, E. G. Fischer, S. N. Hou, and G. Shipway, "New Seismic Requirements for Class I Electrical Equipment," IEEE Paper T 74 048-A, 1974 Winter Meeting of IEEE Power Engineering Society, Institute of Electrical and Electronics Engineers.
6.
NRC Regulatory Guide 1.lCO, " Seismic Qualification cf Clcrtric Equipment for Nuclear Power Plants "
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