ML20210A344
| ML20210A344 | |
| Person / Time | |
|---|---|
| Issue date: | 07/19/1999 |
| From: | Matthews D NRC (Affiliation Not Assigned) |
| To: | Pietrangelo A NUCLEAR ENERGY INSTITUTE (FORMERLY NUCLEAR MGMT & |
| References | |
| PROJECT-689 NUDOCS 9907220076 | |
| Download: ML20210A344 (23) | |
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1 July.19,1999
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l Mr. Anthony Pietrangelo, Director Licensing
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Nuclear Energy Institute Suite 400 1776 l Street, NW Washington, DC 20006-3708
SUBJECT:
STAFF COMMENTS ON DRAFT REVISION TO APPENDIX B i.' NEl 97-04,
" DESIGN BASES PROGRAM GUIDELINES"
Dear Mr. Pietrangelo:
This letter forwards the staff's comments on the draft revision to Appendix B of NE: 97-04 submitted by NEl in a letter dated June 25,1999. As I have previously indicated, the staff intends to continue to work with NEl to attempt to reach consensus on and to endorse an industry guidance document on this subject. This version of Appendix B of NEl 97-04 reflects the results of many meetings and discussions and I believe it is much closer to a document that the staff could endorse.
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i The enclosed staff comments are provided to facilitate the discussion at the public meeting scheduled for July 22,1999. I look forward to discussing these issues with you and reaching a common understanding of 10 CFR 50.2 design bases. Please feel free to call me or Stewart Magruder of my staff with any questions.
Sincarely, Original Signed By:
David B. Matthews, Director Division of Regulatory improvement Programs Office of Nuclear Reactor Regulation l
Project No. 689 l
Enclostre: As stated cc w/ encl: See next page DISTRIBUTION: See attached page Document Name:g:\\RGEB\\sim1\\ comment.ltr.799.wpd "Jee previous concurrence OFFICE RGEB SC:RGEB C:RGEB D:DE NAME SMagruder:sw*
FAkstulewicz*
CCarpenter*
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DATE 7/16/99 7/16/99 (
7/19/99 7/19/99 D:DhPh OFFICE D:DSSA NAME GHolahan*
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DATE 7/19/99 7/\\9 /99 JD t
OFFICIAL OFFICE COPY j
LC 9907220076 990719 PDR REVGP ERGNUMRC PDR L
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j NUCLEAR REGULATORY COMMISSION WASHINGTON D.c. 2066tH1001
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July 19,1999 Mr. Anthony Pietrangelo, Director Licensing Nuclear Energy institute Suite 400 1776 i Street, NW Washington, DC 20006-3708
SUBJECT:
STAFF COMMENTS ON DRAFT REVISION TO APPENDIX B OF NEl 97-04,
" DESIGN BASES PROGRAM GUIDELINES" f
1 l
Dear Mr. Pietrangelo:
This letter forwards the staff's comments on the Raft revision to Appendix B of NEl 97-04 submitted oy NEl in a letter dated June 25,1999. As I have previously indicated, the staff intends to continue to work with NEl to attempt to reach consensus on and to encorse an industry guidance document on this subject. This version of Appendix B of NEl 97-04 reflects the results of many meetings and discussions and I believe it is much closer to a document that the staff could endorse.
The enclosed staff comments are provided to facilitate the discussion at the public meeting i
scheduled for July 22,1999. I look forward to discussing these issues with you and reaching a i
common understanding of 10 CFR 50.2 design cases. Please feel free to call me or Stewart Magruder of my staff with any questions.
I Sincerely, lN
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David B 4%tthews, Director Division of Regulatory improvement Programs Office of Nuclear Reactor Regulation Project No. 689
Enclosure:
As stated cc w/enet: See next page
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c4 DISTRIBUTION: Ltr to NEl re Design Bases Dated _iluly 19. 1999 Central File PUBLIC RGEB r/f OGC ACRS SCollins/RZimmerman WKane BSheron GHolhan J
TCollins j
JStrosnider J
RWessman CACarpenter
- FAkstulewicz TBergman SMagruder JBirmingham GTracy, EDO WLanning, RI BMallett, Ril JGrobe, Rill AHowell, RIV j
OChopra JTatum EMcKenna j
DFischer i
TScarbrough CJackson RWeisman Y
MMarkley, ACRS DAlison -
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l STAFF COMMENTS ON NEl 6/25/99 DRAFT REVISION TO APPENDIX B OF NEl 97-04 General Guidance t
- 1. The staff does not believe that the scope of design bases should be limited to " functional I
requirements or controlling parameters for design established by regulations, license conditions, or orders." We believe that all functions described in the UFSAR that are relied upon to satisfy NRC regulatory requirements (regulations, license conditions, orders, or Technical Specifications) are design basis functions. (See May 14,1999, letter to NEl for preferred wording)
- 2. The staff does not understand what the scope of " analyses of fission product barner integrity"is and why it is used in the second paragraph. The controlling parameters seem to be bounded by the phrase "or otherwise chosen as reference bounds for design to meet design bases functional requirements."
- 3. The structure of the guidance is confusing. The staff recommends clarifying the definition of design bases functions and design bases values in separate paragraphs.
Specific Guidance We believe that the bounding conditions under which SSCs must perform design bases functions include normal operation. In particular, some fuel design parameters are derived from normal operating conditions. Other systems, such as main feedwater or the condenser, may have design basis functions during normal operation but not during transients.
The criteria used to decide the level of detail requirer' br design basis information should be specified in the guidance. A number of examples are included in which information that apaears to meet the threshold for design basis information is labeled as supporting design information. These examples appear to rely on the fact that the information is below the level of detail required to be considered design basis, however, the basis for this decision is not clear.
Relationship of 10 CFR 50.2 Desian Bases to Licensina Basis and Part 50 Recuirements The requirements in 10 CFR Part 50, Appendix A, for testing, inspection, and quality standards (and, to a lesser extent, the fabrication and construction standards) establish the baud. for an SSC being capable to perform its intended function under the required conditions. This design information is very important in assuring that the likelihood of an accident is very low and that mitigation systems will be capable of reliably performing their intended functions. As a result, the staff belbves that this information should be considered design basis information.
The paragraph focuses solely on design basis functions with no mention of design basis values.
We would either add a statement that design basis values are also derived from the sources discussed in the paragraph or make it clear that the paragraph only applies to design basis functions.
Enclosure
o Relationshio of 10 CFR 50.2 Desian Bases to 10 CFR 50.59 The staff generally agrees with NEl's language, however, we would clarify that supporting design information is only controlled in accordance with 10 CFR 50.59 if it is contained or l
incorporated by reference in the UFSAR. Also, the last sentence should be corrected to read i
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" methodology used in establishing design bases orin the safety analyses j
Relationshio of 10 CFR 50.2 Desian Bases to FSARs 4
The guidance statements that the 10 CFR 50.2 design bases have remained relatively fixed is a very broad generalization. There are significant aspects of plant design bases that have changed throughout the years for some plants. Additionally, the bounding values and controlling parameters chosen by individual plants also vary significantly. Although many plants share some aspects of their design basis, the staff is unwilling to endorse this generalization and does not believe that it is a necessary part of the guidance.
Relationshio of 10 CFR 50.2 Desian Bases to Reaulatorv Guidance and NRC Commitments I
We suggest changing the emphasis of the paragraph as follows:
j Regulatory guidance that has been committed to, and other commitments, may constitute 10 CFR 50.2 design bases. For example, a guidance document may be the source of a particular controlling parameter chosen by a licensee as a design br.is requirement...
l Relationship of 10 CFR 50.2 Desian Bases to Desian Basis Documents
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The last sentence should be reworded so that it is clear that design basis information provided in the DBD,? should be consistent with the 10 CFR 50.2 design bases and associated j
description presented in UFSARs and not vice versa.
l Relationshio cf 10 CFR 50.2 Desian Bases to Topical Desian issues i
The staff generally agrees with NEl's language, however, we would add a statement to indicate
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that the list is not all inclusive. We would also add Degraded Voltage to the list.
Relationship of 10 CFR 50.2 Desian Bases to Individual SSC Functions The staff agrees with most of this paragraph, however, we are concerned about apparent
- inconsistencies in NEl's statements regarding the scope of design bases functions.
Specifically, the staff believes that the scope of design bases functions is not limited to "those that are requireo to maintain the integrity of fission product bnrriers under required conditions"
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as stated in the first sentence. Rather, as discussed in our letter dated May 14,1999, the staff believes that the 10 CFR 50.2 design basis functions of a plant's structures, systems, and components, are the functions described in the UFSAR relied upon to satisfy NRC regulatory requirements.
l The staff generally agrees with the rest of the paragraph if it assumes that functions that are
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required for defense-in depth, accident prevention, and those intended to assure reliable i
accident mitigation are included in the scope of design bases functions.
l Examoles of 10 CFR 50.2 Desian Bases and Supportina Desian Information i
Recommend rewriting the introductory paragraph as follows:
The examples that follow reflect the preceding framework guidance and are not intended to provide a complete description of the design bases for a given system. The examples are meant to illustrate the type of information that is considered to be 10 CFR 50.2 design bases versus what is considered to be supporting design information. Individual licensees may identify additional or different functional requirements or controlling parameters based on plant-specific factors. The examples are not meant to be representative of a particular plant or plant type.
The staff believes that it is important to include examples of Motor Operated Valve and Turbine Generator design bases in the guidance.
4 Specific comments on the examples are provided next in the form of L:'nd-written markups to the NEl document.
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NRC S T A % C o m m e d T s o t)
DRAFT Revised Appendix B to NEl 97-04 j
JbLy M MM i
Examples of 10 CFR 50.2 Design Bases and Supporting Design Information The examples that follow reflect the preceding framework guidance.
The examples illustrate the type of information considered to be 10 CFR 50.2 design bases and the distinction of 10 CFR 50.2 design bases from supporting design information. Individual licensees may identify additional or different design bases functional requirements or controlling parameters based on plant specific factors.
DRAFT - BWR Containment System 10 CFR 50.2 Design Bases Examples of Design Bases Controlling Functional Requirements Parameters Chosen as Reference Bounds for Design A. The Containment System (including
- 1. The Containment System shall provide a the containment structure and barrier which, in the event of a loss-of-isolation system) shall provide an coolant accident (LOCA), controls the essentially leak-tight barrier against release of fission products to the secondary the uncontrolled release of containment and the environment to ensure rr.dic9ctivity to the environment and that any radiological dose is less than the ensure that the containment design values prescribed in 10 CFR Part 100.
conditions important to safety are not exceeded for as long as postulated
- 2. The Containment System shall be capable accidents require.
of maintaining its leakage rate performance for at least 30 days following the accident.
Basis:
GDC 16, Containment design
- 3. The Atmospheric Control (ACS) shall GDC 38, Containment heat removal establish and maintain the containment e
GDC 50, Containment design basis atmosphere to less than X.X% by volume e
GDC 51, Fracture prevention of oxygen during normal operating conditions.
e containment pressure boundary GDC 54, Piping systems penetrating
- 4. The containment shall be designed to e
containment withstand the design basis pressure of XX psig.
Draft Revised NEl 97-04, Appendix 8 5
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B. The containment isolation system shall
- 1. The MOVs in the containment isolation l
be capable of rapid, automatic isolation system shall be capable of closing against of all piping that penetrates the the calculat)e naak design basis accident containment boundary upon receipt of pressure idY seconds llowing receipt of a a containment isolation signal.
containment ' solation signal.
Basis:
GDC 50, Containment design basis Trzua0E 6ASI5 FOR D ME-e GDC 56, Primary containment l
l wolation Topical Requirements (Examples) l C. The containment shall be designed to See draft example Topical Design Bases for withstand the effects of earthquakes, seismic and tornadoes (attached.)
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tornadoes and other natural phenomena without loss of capability to perform its safety function.
Basis:
GDC 2, Design bases forprotection against naturalphenomena l
D. The containment isolation system shall See draft example Topical Design Bases for be designed to have sufficient Single Failure (attached),
redundancy to perform its safety function in the event of a single failure.
Basis:
GDC 54, Piping systems penetrating containment GDC 56, Primary containment e
isolation)
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E. Class 1E components in the See EQ Topica1 Design Bases containment isolation system shall be environmentally qualified to perform their safety function under worst case design basis accident conditions..
Basis:
GDC 4, Environmental and dynamic
_, effects design bases)
Draft Revised NEl 97-04, Appendix B 6
l Examples of Supporting Design Information for the BWR Containment System The containment structure is designed to withstand coincident fluid jet forces associated with the flow from the postulated rupture of any pipe within 1
containment.
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. The containment is designed to permit and facilitate initial demonstrations of structural capabilities at test pressures up to and including 1.15 times the design pressure.
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. The containment isolation valves are designed and fabricated in accordance with j
4 The containment is designed to meet the leakage testing requirements of 10 CFR 50, Appendix J.
The containment is designed, fabricated, constructed, end tested as a Class MC
)k vesselin accordance with Subsection NE of the ASME Code.
The drywell is a steel pressure vessel with a spherical lower portions XX feet in diameter, a cylindrical upper portion XX feet in diameter, and an elliptical top head XX feet in diameter.
The pressure suppression chamber is a steel torus-shaped pressure vessel located below and encircling the drywell with a major diameter of XXX feet and a cross-sectional inside diameter of XX feet.
A total of 8 vent pipes having an internal diameter of X feet connect the drywell and the pressure suppression chamber.
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Draft Revised NEl 97-04. Appendix B 7
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DRAFT - PWR Auxiliary Feedwater System 10 CFR 50.2 Design Bases Examples of Design Bases Controlling Functional Requirements Parameters Chosen as Reference Bounds for Design A. The Auxiliary Feeda ater System
- 1. To provide adequate heat removal from gAFW), in conjunction with the the core, the AFW system shall supply d
j "gcondensate storage tank, shall a minimum of XXX gpm of feedwater gg automatically provide feedwater to within xx secs of a design bases event g
the steam generators to remove to the intact steam generator (s) residual he t om the reactor core against a maximum pressure of YYY upon receipt of n AFW auto start psig.
signal) The system safety function shall be to transfer fission product
- 2. In the absence of AC power, the AFW decay heat and other residual heat turbine driven pump shall deliver from the reactor core at a rate such sufficient feedwater flow to remove residual heat from the reactor core that specified acceptable fuel design limits and the design conditions of without relying on AC power for a the reactor coolant pressure period of X hours.
boundary are not excceded.
- 3. The AFW system shall provide sufficient flow to prevent the loss of asis:
GDC 34, Residual heat removal pressurizer vapor space during a feedwater line break with loss of offsite
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power.
err CASE I j
B. From a condition of full power (, the
- 1. A usable volume of XXX gallons shall AFW system shall be capable'of be maintained as a safety grade source providing feedwater for the removal of water in order to satisfy the AFW of reactor core decay heat until system feedwater requirements.
reactor coolant system temperature and pressure are brought to the point at which the RHR system may be placed into operation.
Basis:
GDC 44, Cooling water i
Draft Revised NEl 97-04, Appendix B 8
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Topical Requirements (Examples)
C. The AFW system and the structure See draft examples of Topical Design housing the system shall be designed Bases for seismic and tornado (attached).
. to withstand the effects of earthquakes without loss of capability to perform their safety function. The AFW system shall be protected from tornadoes and other natural phenomena by the structures housing the system.
Basy; GDC 2, Design bases forprotection against naturalphenomena D. The AFW system shall have See draft example Topical Design Bases sufficient redundancy to perform its for single failure (attached).
safety function in the event of a single failure.
Basis:
GDC 44, Cooling water E. Class 1E components i the AFW See EQ Topical Design Bases.
system shall be envir.1 mentally qualified to perform oneir safety function under worst case design basis accident conditions.
Basis:
GDC 4, Environmental cad Dynamic Effects Design Bases Note: This system relies upon performance by interfacing systems of certain design basis functions. For example, generation of auto start signals is a design basis requirement of ESFAS and RPS, and provision of electrical power from separate IE busses is a design basis requirement of the Electrical Distribution System.
Draft Revised NEl 97-04, Appendix B 9
4 Examples of Auxiliary Feedwater System Supporting Design information wphY wy 9 Tu4 l
M o Otsc4eA&i The AFW System cont riven pumps and one turbine driven
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pump configured intk.ains two mo hree trains hich take suction through separate and j independent lines from the condensate storage tank (CSTgto the steam generator secondary side via i 4 dependent connections to the main feedwater line downstream of the feedwater isolation valves.
1 The AFW System provides water to the steam generators for heat removal g
Fu cro,J during plant startup, hot standby, normal cooldown, refueling, and maintenance.
System design pressure is (XXXpsi) and temperature is (XLT F).
The AFW system is designed and constructed in accordance with the rei uirements of ASME Section III(19XX).
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The AFW System provides control room displays of AFW flow, the CST level, Tsr udmr and the steam flew to the AFW pump turbine.
The CST is lined to prevent corrosion and is insulated to mitigate temperature variations.
The AFW System has control devices and status lights on the AFW shutdown panel for each MDAFW pump, each steam supply valve for the TDAFW pump, and each AFW control valve.
9. Provisione are incorporated in the AFW design to allow for periodic operation to c,oc demonstrate performance and structuralleak tight integrity.
Ttsre<=
The AFW pumps are provided with mini flow protection with a mini. flow return line with a flow control valve which isolates when the flow exceeds a preset minimura.
The AFW motor driven pumps are horizontal, centrifugal pumps driven by electric motors.
M $Hout0 6E. DC.st6N BASES Draft Revised NEl 97-04, Appendix B 10
DRAFT - Emeroency Diesel Generator Sysjem to CFR 50.2 Design Bases Design Bases Controlling Parameters Chosen as Functional Requirements Reference Bounds for Design
.xxvt wpic. nae t cAPAury Aan zApqwty TD l
r A. The Emergency P!asel
- 1. Toi
- 25E c,f powerime all required emergency loads under
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Generator Syster i EDG) worst-case loading conditions, EDGs shall have a minimum j
r, hall be capable v continuous rating of XXXX kW.
automatic ally starting i
and Ming sufficient 2.FThe EDG fuel oil supply system shall be designed with 'FM'*
i A AC power to the sufficient fuel oil storage to supply the minimum number of i di L esels required for X uo,ye of ope ation.
em rgency buses to gg g,
, y am powe required opery emergency loads during
- 3. The air start receivers shall have sufficient capacity for at least X starts without rechargmg.
ro the worst loadm.g W
situations, shut down the
- 4. Each diesel generator shall be capable of operatm.g in its reactor, and maintain it service environment during and after a design bases event in a safe shutdown without support from offsite power. Each generator shall be condition in the event of able to start and operate with no environment cooling a loss of offsit6 power or available for the time required to sequence the cooling degraded bus condition.
equipment on to the bus bar.
Easis:
- 5. The EDG speed and voltage controls shall be designed to GDC 17, Electricafpower achieve rated voltage and frequency and accept load within systems)
XX seconds after receipt of an engine start signal.
GOC. G
- Testeened Ado
- 6. The EDG auto. start signals shall be initiated by x==
MTW of EL E'T*,5(-
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.., bux; for loss of voltag.and Pod EyN5 degraded bus voltage conditions, A,40 AmoGrr use*L.
Gry., {. EmbamegAL
- 7. The EDG System shall be designed such that at no time
- "N 66 S'd N during the EDG loading sequence shall the voltage decrease c,g g gm g gc.,
to less than 75% G12^ V) of nominal.
- 8. The EDG System shall be designed such that the voltage will be restored to within 10% G744 ") of nominal in less than (o4T40% of each load block time intervr.1, ucept duriv the first load block when the voltage shall be restored to 100% (4160 V) of nominal prior to the start of the second load block.
- 9. The EDG System shall be designed such that at no time during the loading sequence will the frequency decrease to less than 95% (57 Hz) of nominal uxpt d=in;; the f.M had Mock.
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$EE r4 ext PAGC Draft Revised NEl 97-04, Appendix B 11
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- 10. The EDG System shall be designed such that frequency will be restored to within 2% of nominal in less than 60% of each load-block time interval. During recovery from transients caused by the disconnection of the largest load, the speed of the diesel generator unit should not exceed the nominal speed plus 75% of the difference between nominal speed and over-speed trip setpoint or 115% of nominal, whichever is lower. Furthermore, the transient following the complete loss of load should not cause the speed of the unit to attain the overspeed trip setpoint.
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g Topical Requirements (Examples)
B. The EDG System shall be designed for See draft example Topical Design Bases for Protection Against Natural seismic and tornado ( attached).
Phenomena without loss of capability to perform its safety function 4 The structures housing the system and the system itself are designed to withstand the effects of earthquakes.
The system is protected from other natural phenomena by the structures l
housing it.
Basis:
GDC 2, Design bases for protection against naturalphenomeaa I
C. The EDG system shall have sufficient See draft example Topical Design Bases for redundancy to perform its safety single failure (attached).
function in the event of a single failure.
Basis:
GDC 17, Electricalpower systems Note: This system relies upon performance by interfacing systems of certain design basis functions. For example, generation of auto-start signals is a design basis requirement of ESFAS and RPS, and provision of electrical power from separate IE busses is a design basis requirement of the Electrical Distribution System.
l Examples of EDG System Supporting Design Information
- When full, each diesel generator fuel oil day tank is designed to provide X hour of operation before starting the first transfer pump. If the automatic transfer pump fails to start, a low level alarm will sound. This alarm providegX hours of fue? oil remaining. A low-low level aljrm warns the6perators to starJthe second (back-up) transfer pump witl(sleast X hour of fuel oil remaininjin the tank.
y OPEAATDA AE.AMiE TIME is OE. Clod Mis 4
Draft Revised NEl 97-04, Appendix B 12 J
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Each day tank is designed and constructed to ASME Code,Section VIII, Division I.
The b has a rating of XXX% ofits continuous rating for a period of 2 continuous hours out of any 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of operation.
The air start receivers provide adequate volume to supply starting air for X engine starts without recharging assuming a leak rate of XX.XX psig per hour and a cranking duration of approximately X seconds or sufficient for 4H&O S engine n.ci;muo.5tAATS.
. The momentary voltage drop on starting any step ofloads may not drop below XXXX volts at generator terminals and returns to 90% of rated voltage within one'second.
Diesel fuel oil has a minimum fuel oil heating ~ capacity of XXX,XXX BTU / Gallon at XX *F.
The generators meet the guidance of Regulatory Guide 1.6 -Independence Between Redundant Standby (Onsite) Power Sources and Between Their 3
Distribution Systems; Regulatory Guide 1.9 - Selection of Diesel Generator Set Capacity for Standby Power Supplies and NEMA MG1.
R, G 1,137 - Dne.sE.L GE.aEAATeA fuel oit- 'Y N S A00 T.EG.E.
6s y gs et rea, cases,, gogupiay,g, yo rgsy,,4.,, gym,gc,y 086.ss.s 4m taATon w iTs ta s EA. As em t E o 9s ett Euse: rec P s.>sa sys%
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t utQ.AA fous.A PcAp'tg A'T J
yst swog.o m9s - Fust ont sy w.s % stw oty otp au ces t.AAT=As
! Draft Revised NEl 97 04, Appendix B 13
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DRAFT-Seismic Tonical Design Bases 4
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10 CFR 50.2 Design Basis Functional Requirements
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I Structures, systems, and components important to safety shall be designed to
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withstand the effects of earthquakes without loss of capability to perform their safety function. (GDC 2, Design Bases for Protection Against Natural Phenomena,
' and 10 CFR 100, Appendix A)
Example of Design Bases Controlling Parameters Chosen as Reference Bounds for Seismic Design i
l Structures, systems, and components shall be analyzed and designed to withstand the effects of an operating basis earthquake with a peak ground acceleration of X.Xg and a safe shutdown earthquake with a peak ground acceleration of X.Xg.
Basis: Seismic loadings are characterized by the safe shutdown earthquake (SSE) and the operating basis earthquake (OBE). The SSE is defined as the maximum j
vibratory ground motion at the plant site that can be reasonably predicted from geologic and seismic evidence. The OBE is that earthquake which, considering the l
local geology and seismology, can be reasonably expected to occur during plant life.
i Examples of Seismic Supporting Design Information Seismic classification of plant structures, systems, and components is in accordance with NRC Regulatory Guide 1.29, Seismic Design Classification.
Seismic Classification of radioactive waste management systems, structures and components is in accordance with NRC Regulatory Guide 1.143, Design Guidance For Radioactive Waste Management Systems, Structures, And Components Installed In Light Water Cooled Nuclear Power Plants.
. Seismic design response spectra are in conformance with NRC Regulatory Guide 1.60, Design Response Spectra for Seismic Design of Nuclear Power Plants.
Seismic damping values used in the structural dynamic analysis are the same as those provided in NRC Regulatory Guide 1.61, Damping Values for Seismic Design of Nuclear Power Plants with the exception of damping values for cable j
trays and supports. The damping values for cable trays and supports are values i
based on test reports (specific reference) and were approved by the NRC in (specific reference).
Draft Revised NEl 97-04, Appendix B 14
For Seismic analysis of ASME Boiler and Pressure Vessel Code,Section III, Division 1, Code Class 1,2, and 3 piping systems, ASME Code Case N 411 damping values given in Reference E may be used provided the following criteria are satis 6ed:
- 1. Increased pipe deflections due to greater piping flexibility do not violate plant separation criteria.
- 2. Criteria outlined in NRC Regulatory Guide 1.61 do not mix with the criteria of Code Case N-411 for a given piping anelysis.
- 3. With the exception of the stress calculations described in Reference F, Code Case N-411 damping values are not used in conjunction with multiple response spectrum methodology piping analysis.
g. Seismic Category II systems, equipment, and components installed in Seismic Category I structures who failure could result in loss of required safety function of Seismic Category I structures, equipment, systems, or components are either separated by distance or barrier from the affected structure, system, equipment, or component or designed together with their anchorages to maintain their structural Integrity during the SSE.
Category II structures are designed using the Uniform Building Code, XXXX o
edition.
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$40ut 0 &E. OEst69 6As 6s Draft Revised NEl 97-04, Appendix B 15
DRAFT Tornado Topical Design Bases I
10 CFR 50.2 Design Basis Functional Requirements Structures, systems, and components important to tafety shall be designed to withstand the effects of tornadoes without loss of capability to perform their safety function. (GDC 2, Dcaign Bases for Protection Against Natural Phenomena, and 10 CFR 100)
Examples of Design Bases Controlling Parameters Chosen as Reference Bounds for Tornado Design Seismic Category I structures housing safety related equipment, systems, and j
components shall be designed to withstand the effects due to the design basis tornado as described as follows:
Maximum peripheral tangential velocity - xxx mph.
Translational velocity - xx mph maximum / x mph minimum.
Maximum wind velocity-xxx mph Radius from the center of the tornado where the maximum wind velocity occurs - xxx ft.
Atmospheric pressure drop - x psi.
Rate of pressure drop - x psi /s.
Basis: Nuclear power plants must be designed so that the plants remain in a safe condition in the event of the most severe tornado that can reasonably be predicted to occur at a site as a result of severe meteorological conditions.
Examples of Tornado Supporting Design Information The parameters which define the design basis tornado conform with those given in U.S. NRC Regulatory Guide 1.76," Design Basis Tornado For Nuclear Power Plants," August 1974, for Region X plant locations.
Tornado wind pressure loadings and differential pressures loadings shall be transformed into effect loads on Seismic Category I structures in accordance with Topical Report XXXX (specific reference).
Draft Revised NEl 97-04, Appendix B 16
Seismic Category II structures, equipment, systems, and components not M
designed for tornado loadings shall be investigated to ensure their failure will not effect the integrity of adjacent Seismic Category I structures. This design ensures that Seismic Category I structures, equipment, systems, and components required for safe shutdown after a tornado will perform their intended safety functions.
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OEclGJ 6AsEs J
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Draft Revised NEl 97-04, Appendix B 17
w DRAFT Single Failure Topical Design Bases 10 CFR 50.2 Design Basis Functional Requirements Fluid and electrical systems required to perform their intended safety function in the event of a single failure shall be designed to include sufficient redundancy and independence such that neither (1) a single failure of any active component (assuming passive components function properly) nor (2) a single failure of a passive component (assuming active components function properly), results in a loss of the capability of the system to perform its safety functions. (GDC 17, Electricalpower systems; GDC 21, Protection system reliability and testability; GDC 24, Separation of protection and control systems; GDC 25, Protection system requirements for reactivity
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control malfunctions; GDC 34, Residual heat removal: GDC 35, Emergency core cooling; GDC 38, Containment heat removal; GDC 41, Containment atmosphere cleanup; GDC 44, Cooling water)
Examples of Design Bases Controlling Parameters Chosen as Reference Bounds for Single Faliure Design Fluid and electrical systems shall be designed to assure that a single failure, in conjunction with an initiating event, does not result in the loss of the system's ability to perform its intended safety function. The single failure considered shall be a random failure and any consequential failures in addition to the initiating event for which the system is required and any failures which are a direct or consequential result of the initiating event. Whenever practical, the design shall provide for a 30. minute delay between the indication of the initiating event and the initiation of any operator action, either locally or remotely, from any control panel.
Easis: These criteria ensure that the requirements of 10 CFR 50 are addressed regarding the design against single active or passive failures in safety-related systems following various initiating events.
Single Failure Supporting Design Information An initiating event is a single occurrence, including its consequential effects, o
M that places the plant or some portion of the plant in an abnormal condition. An initiating event and its resulting consequences are not a single failure. An initiating event can be a component failure, natural phenomenon, or external
- Draft Revised NEl 97-04, Appendix B 18
p a.l m,"
d man made hazard.
Active components are devices characterized by an expected signi5 cant change Me of state or discernible mechanical motion in reaponse to an imposed demand upon the system or operation requirement. Examples of active components include switches, circuit breakers, relays, valves, pressure switches, turbines, motors, dampers, pumps, and analog meters, etc.
~ M.: Passive components are devices characterized by an expected negligible change of state or negligible mechanical motion in response to an imposed design basis load demand upon the system. Examples of passive components include d!::,
. fuses, piping, valves in stationary positions, fluid filters,"a+a ' p,
cabinets, cases, etc.
An active component failure is a failure of an active component to complete its 1
intended safety function (si
'-- " Spurious action of a powered component originating witLn its automatic actuation of control systems shall be regarded as an active failure unless specific features or operating restrictions preclude such spurious action.-
., A passive component failure is a failure which limits the component's E
effectiveness in carrying out its design function (s). When applied to a fluid
)
system, this means a breach of the pressure boundary resulting in abnormal leakage. Such leakage shall be limited to that which results from a single pump l
seal failure, a single valve stem packing failure, or other single failure mechanism considered possible by a systematic analysis of system components.
The design of safety-related systems (including protection systems) is consistent with IEEE Standard 3791972 and Regulatory Guide 1.53 in the application of the single-failure criterien.
9 The protection system is designed to provide two, three, or four instrumentation channels for each protective function and two logic. train circuits. These redundant channels and trains are electrically isolated and physically separated.
Thus any single failure within a channel or train will not prevent protective a<: tion at the system level, when required, je
.. The Class IE electric systems are designed to satisfy the single failure criterion.
. Design techniques such as physical separation, functional diversity, diversity in component design, and principles of operation, shall be used to the extent necessary to protect against a single failure.
t SRw@
ef DES 164 -6As$5 F it DES @ MSES - 9ar HELE55Ath.y fcA sp6g pgwg Drsft Revised NEl 97-04,' Appendix B 19
. Nuclear Energy Institute -
' Project No. 689 cc:
Mr. Ralph Beedle Ms. Lynnette Hendricks, Director Senior Vice President Plant Support and Chief Nuclear Officer Nuclear Energy institute Nuclear Energy Institute Suite 400 Suite 400 1776 i Street, NW 1776 i Street, NW Washington, DC 20006-3708 Washington,' DC 20006-3708 Mr. Alex Marion, Director Mr. Charles B. Brinkman, Director Programs Washington Operations Nuclear Energy Institute ABB-Combustion Engineering, Inc.
Suite 400 12300 Twinbrook Parkway, Suite 330 1776 l Street, NW Rockville, Maryland 20852 Washington, DC 20006-3708 Mr. David Modeen, Director Engineering Nuclear Energy Institute Suite 400
- 1776 l Street, NW Washington, DC 20006-3708 Mr. Anthony Pietrangelo, Director.
Licensing.
Nuclear Energy institute Suite 400 1776 i Street, NW Washington, DC 20006-3708-Mr.-Nicholas J. Liparulo, Manager Nuclear Safety and Regulatory Activities Nuclear and Advanced Technology Division Westinghouse Electric Corporation P.O. Box 355 Pittsburgh, Pennsylvania 15230 Mr. Jim Davis, Director Operations Nuclear Energy Institute -
Suite 400 1776 i Street, NW Washington, DC 20006-3708 j