ML20059M916
| ML20059M916 | |
| Person / Time | |
|---|---|
| Issue date: | 11/10/1993 |
| From: | Thadani A Office of Nuclear Reactor Regulation |
| To: | Larkins J Advisory Committee on Reactor Safeguards |
| References | |
| ACRS-GENERAL, GL-86-10, NUDOCS 9311190448 | |
| Download: ML20059M916 (67) | |
Text
%m,
x y.
.y.,
- I
~
[ ;
.1 e
I'
^
e 3
i
,x W*;y a
y LNovember;10,fl993f p
o_ 'y+
!MEMORANDUMdO: John.iTL Larkins?
Executi've-Director;for'AdvisopyiCommitteeJon Reactorj y; D Safeguards / Advisory Committee on Nuclear WasteL N
F
~
__f FROM:
- Ashok?C.'Thadani,' Director,
' Division offSystems safety and Analysisf CH
- Office:of Nuclear Reactor 1 Regulation:
SUBJECT:
'ACRS SUBCOMMITTEE MEETING ON THERM 0-LAGl t
On October 29, 1993, the NRR. staff briefed the Commission on theJstatus ofJ actions to resolve the. Thermo-Lag. fire barrier ' issues. The Commission.
requested thht the NRC siaff inform the Advisory Committeefon Reactor-._
-Safeguards (ACRS) of the technical differences that= remain between the staff and the Nuclear Utility Management'and Research Council 1 (NUMARC)~ on: the.NUMARCi test program acceptance: criteria.- In respon'se to theLCommissionLrequest, a meeting with the ACRS Subcommittee for Auxiliary and Secondary Systems;has?
been scheduled for November 19,.1993. To facilitate::the subcommittee meeti.Sg, I am sending you the following documents-n 1.
A comparative ' text: version of the final _ draft-of Supplement 1 to t
4 GL 86-10, "FireLEndurance Test Acceptance Criteria:for. Fire:Barrieri Systems Used'to Separate Redundant Safe Shutdown' Trains Within the.Same Fire Area" (Enclosure 1). The comparativettextiversion shows the n
substantive-revisions made by the staff in response toLcomments received
,a during the; comment period.
~~
~
2.
The staff responses-to public commentsLon the. proposed GL 86 1 Supplement 1 (Enclosure _2).
~'
3.
Three comparison tables of various fire endurance testin' g l criteria' 7
~
,'t (Enclosure 3).
Enclosures 1 and 2 are final drafts that are currently under NRR'~ management review.
Following management approval, they will ~ be provided.to the^ Committee?
to Review Generic Requirements (CRGR) with' our request for CRGR~ approval of Supplement I to GL'86-10.
3a If you need additional information, please call' Steven West at 504-1220 or-q Patrick Madden at 504-2854.
g Ashok C. Thadani, Director- _
Division of-Systems Safety and Analysis
~
Office of Nuclear Reactor Regulation
Enclosures:
As stated cc:
D. Coe 2-8 Distr bution Se next age-
/
f Q e/S 7 O/$/7Wf f. n SPLB:DSSA SPLB:DSSA SPLB:DSSA D:DSSA
&M M85-45/d '
.l L
D0udinot*
SWest*
CMcCracken*
AThadani l
/
11/10/93 11/10/93 11/10/93 11/((f93 002063
- See previous concurrcnce 3
,[G:\\THERMOLA\\ZACRS.D01]-
Y- ] $ [ A p y i n CI f
% v-p s
'G~ 1'
~ ' ' ~ "
Nh 4 M 9i L
~9311190448 931110 d'
'PDR ACRSt '
GOERALH ppR. 3 l
s y
g y
p
<w MEMORANDUM T0:
John T. Larkins Executive Direc. tor for'ACRS/ACNW~
h FROMi
-Ashok C.'Thadani, Director.
Division of Systems Safety andl Analysis
~
SUBJECT:
ACRS SUBCOMMITTEE MEETING ON THERMO-LAG' On October 29, 1993, the NRR staff briefed the Commission on th status of actions to resolve the Thermo-Lag fire barrier issues.
The.C nission:
requested that the NRC staff inform the Advisory Committee-Reactor Safeguards (ACRS) of-the' technical differences' that remain /6etween the-staff _.
H and the Nuclear Utility Management.and Research Council NUMARC) on the-NUMARC:
test program acceptance criteria.
In response to the mmission request, I-have scheduled a meeting with the ACRS Subcommittee f r~ Auxiliary and Secondary Systems-for November 19,L1993. To.facili te the subcommittee meeting, I am sending you the following document '
1 1.
A' comparative text version of the final aft of Supplement 1 to GL 86-10, " Fire Endurance Test Accept Criteria for Fire Barrier Systems Used to Separate Redundant S.
Shutdown Trains Within the Same Fire Area"- (Enclosure 1). The compafative text version shows the substantive revisions made by the,taff in response to comments received' during the comment period.
2.
The staff responses to publi comments on the proposed GL 86-10 Supplement 1 (Enclosure 2).
3.
Three comparison tables f various fire endurance testing criteria (Enclosure 3).
Enclosures 1 and 2 are fip 1 drafts that are currently under NRR management
~
review.
Following management approval, they will be provided-to the Committee to Review Generic Req rements (CRGR) with our request for.CRGR approval _of-4 Supplement I to GL 8 0.
3 If you need additig al information, please call Steven West at 504-1220 or Patrick Madden a 504-2854.
j/
Ashok C. Thadani, Director Division of Systems Safety and Analysis Enclosure As state,d D/ Coe cc:
lD Distribution: See next page 4
SPHA SPLB:DSSA ShtB:DSSA-D:DSSA 00d i'RSSA -
not SWest CMcCracken AThadani i
11//#/93 11/g/93 II/p/93 11/ /93
[G:\\THERMOLA\\ZAt.RS.001]
c..,
p.,.y
'yner#a, J
n.
u_
'7 0
UNITED STATES 3(
NUCLEAR REGULATORY COMMISSION
\\
,/
WASHINGTON, D.C. 20555-0001 November _10, 1993 MEMORANDUM T0:
John T. Larkins Executive Director for Advisory Committee on~ Reactor Safeguards / Advisory Committee on Nuclear Waste FROM:
Ashok C, Thadani, Director Division of Systems Safety and Analysis Office of Nuclear Reactor Regulation
SUBJECT:
ACRS SUBCOMMITTEE MEETING ON THERMO-LAG On October 29, 1993, the NRR staff briefed the Commission on the status of actions to resolve the Thermo-Lag fire barrier issues.
The Commission requested that the NRC staff inform the Advisory Committee on Reactor Safeguards (ACRS) of the technical differences that remain between the staff" and the Nuclear Utility Management and Research Council (NUMARC) on the NUMARC test program acceptance criteria.
In response to the Commission request, a meeting with the ACRS Subcommittee for Auxiliary and Secondary Systems has been scheduled for November 19, 1993. To facilitate the subcommittee meeting, I am sending you the following documents:
1.
A comparative text version of the final draft of Supplement I to GL 86-10 " Fire Endurance Test Acceptance Criteria for Fire Barrier Systems Used to Separate Redundant Safe Shutdown Trains Within the Same Fire Area" (Enclosure 1). The comparative text version shows the substantive revisions made by the staff in response to comments received during the comment period.
2.
The s',aff responses to public comments on the proposed GL 86-10 Supplement 1 (Enclosure 2).
3.
Three comparison tables of various fire endurance testing criteria (Enclosure 3).
Enclosures 1 and 2 are final drafts that are currently under NRR management review.
Following management approval, they will be provided to the Committee to Review Generic Requirements (CRGR) with our request for CRGR approval of Supplement I to GL 86-10.
~
If you need additional information, please all Steven West at 504-1220 or Patrick Madden at 504-2854.
g&J gt4 As k 'C. inauam,h Di ision of Systems Safety and Analysis Of ice of Nuclear Reactor Regulation
Enclosures:
As stated cc:
D. Coe M. Taylor H. Pastis
q
- w (y "
TNovember:10,;1993:
ye a
n g
w.4>
MEMORANDUM TO::
John T. Larkins
[
E
- Executive ~ Director for ~ Advisory-Comitte'e on Reactor; Safeguards / Advisory Comittee 2 on:. Nuclear.Wastej FROM:
Ash'oklC.;Thadani', Director I _
Division of Systems Safety and AnalysisT Office 'of Nuclear Reactor Regulation?
^
SUBJECT:
'ACRS SUBCOMMITTEE MEETING:0N THERMO-LAG:
yo On October 29, 1993, the NRR staff briefed the Comission on thelstatus'of ~
actions to resolve the Thermo-LagLfire barrier ~ issues. The-Commission' requested that the NRC staff inform the _ Advisory Comittee on Reactor l -
Safeguards (ACRS) of the~ technical differences that remain between' the staff?
and.the Nuclear Utility. Management;and:Research Council (NUMARC) onlthe NUMARC:
test program acceptance criteria.. In response. to ithe Comission< request, a' meeting with the ACRS Subcommittee for Auxiliary andLSecondary Systems-has:
-been scheduled for November 19, 1993. To facilitate the subcommittee meeting,-
.;- f I am sending you the followingLdocuments: '
- 1 s
1.
A comparative text version of the: final draft of-Supplement lito i
GL 86-10, " Fire Endurance'~ Test Acceptance Criteria.for Fire Barrier.
Systems Used to Separate Redundant: Safe Shutdown' Trains Within theLSame.
Fire Area"1(Enclasure 1). The comparative text version shows'the-substantive revisions made by the staff.in response to. comments received; during the coment period.
~~
2.
'The. staff responses to public comments on the proposed GL 86-10 Supplement 1 (Enclosure 2).
'~
w 3.
Three comparison' tables of: various fire endurance-testing' criteria.
(Enclosure 3),.
Enclosures 1 and 2 are final draft's that are currently under-NRR management.
review.
Following management approval, they will be providedito the' Committee to Review Generic. Requirements' (CRGR) with our reque'stifor:CRGR! approval; of-Supplement 1 to GL 86-10.
l If you need additional information, please call Steven West at 504-1220 or Patrick Madden at 504-2854.
.g Ashok C. Thadani, Director
- 1 Division' of Systems. Safety and Analysis -
j Office of Nuclear Reactor-Regulation 1
Enclosures:
As stated cc:
D. Coe M. Taylor-H. Pastis Distribution: See next page SPLB:DSSA SPLB:DSSA SPLB:DSSA D:DSSA D0udinot*
SWest*
CMcCracken*
AThadani 11/10/93 11/10/93 11/10/93
-11/((f93-l
- See. previous concurrence
[G:\\THERMOLA\\ZACRS.001]
l
g; y
.s L
MEMORANDUM T0:
John T. Larkins Executive Director for ACRS/ACNW-FROM:
Ashok C. Thadani, Director Division of Systems Safety;and Analysis-
/
SUNECT:
ACRS SUBCOMMITTEE MEETING ON THERM 0-LAG On October 29, 1993, the NRR staff briefed the Commission on th status of'-
actions to resolve the Thermo-Lag fire barrier. issues. The C ' ission requested that the NRC staff inform the Advisory Committee Reactor Safeguards (ACRS) of the technical differences that remain etween the staffc and the Nuclear Utility Management and Research Council VMARC)~ on the NUMARC test program acceptance criteria.
In response to the mmission request, I g
have scheduled a meeting with the ACRS Subcommittee f r Auxiliary and Secondary Systems for November 19, 1993. To facili te the subcommittee meeting, I am sending you the following documents-
'j l.
A comparative text version of the final fraft' of Supplement I to GL 86-10, " Fire Endurance Test Acceptance Criteria for Fire Barrier Systems Used to Separate Redundant Spre Shutdown Trains Within the.Same Fire Area" (Enclosure 1). The comparative text version shows the substantiverevisionsmadebytheJtaffinresponsetocommentsreceived during the comment period.
2.
The staff responses to publi comments on the proposed GL 86-10 Supplement 1 (Enclosure 2).
3.
Three comparison tables f various fire endurance testing criteria (Enclosure 3).
Enclosures 1 and 2 are fipal drafts that are currently under NRR management review.
Following manag(ment approval, they.will be provided to the Committee te Review Generic Req tements (CRGR) with our request for CRGR approval of Supplement I to GL 8 0.
If you need additi. al information, please call Steven West at 504-1220 or Patrick Madden a 504-2854.
Ashok C. Thadani, Director Division of Systems Safety and Analysis Enclosure :
As state
/
D.I Coe cc:
Distribution:
See next page N
SPH4pSA SPLB:DSSA S
- DSSA D:DSSA 00d inot SWest CMcCracken AThadant 11/#/93 II/g/93 11/p/93 11/ /93
[G:\\THERMOLA\\ZACRS.D01]
k
- s a;
r
. DISTRIBUTION.w/ enclosures:
SPLB.TSI File O
Central File NRC PDR DISTRIBUTION W/out enclosures:
JTaylor JSniezek FMiraglia WRussell AThadani CMcCracken CBerlinger
..SWest PMadden LPlisco JBlaha D0udinot GPA/PA WDean ETana, PMAS JLee MCallahan GMulley P0' Dell, 12E4 EPawlik 4
I
\\,U
yy._-.
n w p; w
^
y.;
~
y t
'6
.h_
- 4
- EnElosure'll ~
Y FINAL DRAFT; FIRE ENDURANCE-TEST ACCEPTANCE CRITERIA FOR l
. FIRE BARRIER SYSTEMS USED T0 SEPARATE REDUNDANT SAFE SUUTDOWN:TRAINSi r
WITHIN THE SAME FIRE AREAL m
b I.
SACKGROUND cable tray fire. This fire'had,a. significant impact on operatora responsectol s
In 1975, the Browns Ferry Nuclear. power plant. experienced a:serio'us electricall u
s the event from a safety perspective. The fire caused spurious instrumentationJ lH J
indications and affected the' control of several safety: systems. ;As a results of this fire, the NRC issued the following. fire protection guidelines andi regulations concerning fire protection programs. at: n'uclear power plants:
May 1, 1976 Branch Technical. Position -(APCSB) 9.5-1, f" Fire ~
~
Protection ~ Program."
February 24, 1977 Appendix A to Branch Technical Position:APCSB!
O 9.5-1, " Guidelines'for Fire Protection for.-
j Nuclear Power Plants-Docketed Prior to July 1, ~
3
-r 1976."
q February 19, 1981 10 CFR 50.48, " Fire Protection.'"-
February 19, 1981 Appendix R tot 10.CFR 50, " Fire Protection.
~
Program for Nuclear Power Facilities Operating, Prior to January 1979."'
u July 1981 NUREG-0800, Standard Review Plan (SRP), 9.5;1,-
m
'" Fire Protection for Nuclear. Power Plantsi" In addition to the above fire protection guidance' and regulations, the NRC,-in-an effort to clarify its fire protection requirements to the industry, issued-Generic Letter (GL) 81-12, " Fire Protection Rule;(45 FR 76602, November 19, 1980)," February 20, 1981; GL 83-33,."NRC Position on Certain q
Requirements of Appendix R to 10_CFR.50," October:19,~1983; and GL-86-10,..
" Implementation of Fire Protection Requirements," April /24, 1986. -Gl. 86-10,-
which took precedence over previous staff guidance, provided staff interpretations to Appendix R and answers to industry questions regarding the:
d implementat un of Appendix R.
The NRC, in an effort to give the licensees.
a flexibility o make changee. to its plant. specific fire' protection program,.
d issued GL 88-12, " Removal of Fire Protection Requirements From Technicalt Specifications," A0$6st?2}fl988. Through the' implementation:and thefadoption j
of a standard licsisH66difibh,; a. licensee 'can make chahges which do riot-l adversely affect the ability to achieve and maintain ~ post-fire safe. shutdown
(
~
to its fire protection program in accordance with_10 CFR150.59.c
]
o The aforementioned NRC documents provided the industry with NRC' staff guidance concerning fire barriers separating plant fire areas, including-the firef resistance (endurance) ratings for the barriers and the qualification testing:
1 lq k
a
+
=-
. 'lQy L L that establishes their_ fire resistance ratings.
In. addition, the documents-provided guidance on combustibi1My of structural materials. and the testing required to demonstrate low flame spread properties.
The_following sections of this document provide the objective for providing safe shutdown related fire barriers in nuclear power plants, definition _ of -
fire protection terms related to fire barriers, and the. NRC fire endurance:
testing acceptance criteria for fire barriers used to separate. safe shutdown-functions within the same fire area.
II.
OBJECTIVE OF FIRE BARRIERS USED TO SEPARATE SAFE SHUTDOWN FUNCTIONS WITHIN THE SAME FIRE AREA Fire rated barriers are used in nuclear power plants to provide fire area separation between redundant safety'related components and safe shutdown functions.
They provide fire resistance protection, as required.by-Appendix R', to one safe shutdown train in those fire areas which contain both trains. The objective of the safe shutdown related Appendix R fire.
barrier is to ensure that a safe shutdown train is conservatively protected from fire-relat > thermal damage. The necessity for these fire barriers has been verified *-
'iple probabilistic risk assessments (PRAs). These PRAs indicated that, L tith fire barriers. installed, fires are a major contributor to cor..aelt probabilities.
It is the position of the NRC that fire endurance ~ ratings of building construction and materials are demonstrated by _ testing fire barrier assemblies..
in accordance with the provisions of the applicable sections of NFPA 251,-
" Standard Methods of Fire Tests of Building Construction and Materials," and ASTM E-119, " Fire Test of Building Construction and Materials."- Assemblies that pass specified acceptance criteria (e.g., standard time-temperature fire endurance exposure, unexposed side temperature rise, and hose stream impingement) are considered to have a specific fire resistance rating. to GL 86-10, " Interpretations of Appendix R," provided additional guidance with respect to the term " free from fire damage."
Interpretation 3,
" Fire Damage," states, "In promulgating Appendix R, the Commission has-provided methods acceptable for assuring that necessary structures, systems, and components are free from fire damage (see Section III.G.2a, b, and c),
that is, the structure, system or component under consideration is capable of performing its intended function during and after the postulated fire, as needed."
GL 86-10, Response 3.2.1, also stated that, "The resulting 325 *F cold side temperature criterion is used for cable tray wraps because they perform a fire barrier function to preserve the cables free from fire damage.
It is clear that cable that becins to dearade at 450 *F is free from fire damage at 325 *F."
(Emphasis added.)
In addition, the staff. response stated that, "for newly identified conduit and cable trays requiring such wrapping new materials 1
For advanced reactor designs, redundant safe shutdown functions are required to be located in separate 3-hour fire areas.
L
7 m
,[Cl m
7
_3_
which meet the 325 *F criterion'should be used, or justification should be provided for the use of material which does not meet the 325 *F criterion.
s This may be based on an analysis demonstrating that the maximum recorded temperature is sufficient 1v below the cable insulation ignition; temperature."
(Emphasis added.)
~ '
The basic premise of the NRC fire resistance criteria-is phat' fire barriers 1 which do not exceed 163.*C [325 *F] cold side temperature and pass.the hose
~
stream test provide adequate assurance that the shutdown capability _is.
protected without further analyses.
If the temperature criteria;is exceeded, sufficient additional information is needed to perform an engineering evaluation to demonstrate that the shutdcwn. capability is protected.-
III. DEFINITIONS In order to support the understanding of the technical terms used throughout this document, the following definitions are provided.
Combustible Material - Material that does not meet the definition of non-combustible.
Fire Barrier - Those components of construction (walls, floors and their supports), including beams, joists, columns, penetration seals or closures, fire doors, and fire dampers that are rated by approving laboratories in hours of resistance to fire and are used to prevent the' spread of fire.
Fire Resistance Ratina - The time that materials of a test assembly have withstood a standard ASTM E-119 fire exposure and have successfully met the established test acceptance criteria (Fire Barrier Testing Acceptance Criteria refer to Sections IV, V, and VI).
Noncombustible Material - (a) Material which in the form in which it.is used and under the conditions anticipated, will not ignite, burn, support combustion, or release flaw.able vapors when subjected to fire or heat; (b)
Material having a structural base of noncombustible material, with a surfacing not over 1/8-inch thick that has a flame spread rating of not higher than 50 1 :
when measured using ASTM E-84 Test " Surface Burning Characteristics of Building Materials."
(Note - There is an exception to this definition as defined by BTP Appendix A, Position D.I.d.
This position allows the use of combustible interior finishes when listed by a nationally recognized testing laboratory, such as Factory Mutual or Underwriters Laboratories, Inc. for a flame ' spread, smoke and fuel contribution of 25 or less' in its use configuration.)
2 The 163 *C [325 *F] temperature cordition was established by allowing the 4nternal temperature on-6ffthsliidbips.3dlifdsTof["thsTFiEeuiRfi?EisFrie?
to rise 139 *C (250 'F)iftssEijieETsibsfaiMheiunset[6fsthe=fiestexoos~ rd,a t.h5FN.6c5..uplisis. it. mig. g.,p th
.- _ ~. _u g
_.g.
m.
9:
0.
Raceway Fire Barrier -'Non-load bearing partition type envelope system installed around electrical components and cabling that are rated by cpproving hber:teries in hours of resistance to fire and are used to maintain safe shutdown functions free of fire damage.
REE53VMCi61'iTrifsEEEMiifs~7fEEGET6x~esWEdTEWe~EisTs&fffEST componen tsithstlapei used ! to /sspp~b rtfind " routescabl es!!f rom t Ecuititerinidiffon t6ckcMititegn[natjgsf~~~
^ ~ ~ ~ ~ ~~ ~ '" ^ "
IV.
FIRE ENDURANCE TESTING ACCEPTANCE CRITERIA"FOR FIRE BARRIER WALLS, FLOOR 3, CEILINGS,sFREEiSTANDING?EQUIPMENTfENCLOSURES USED TO SEPARATE
~
SAFE SHUTDOWN FUNCTIONS WITHIN~ THE~SAME^ FIRE ~ AREA ~
To demonstrate the adequacy of fire barrier walls, floors, ceilings, and.
enclosures, barrier designs should be verified by. fire endurance testing. NRC fire protection guidance refers to the guidance of NFPA 251 and ASTM E-Il9 as acceptable test methods for demonstrating fire endurance performance.
The following are the fire endurance testing acceptance criteria: for the subject fire barriers:
The fire barrier design fias withstood the. fire endurance test without-the passage of flame or the ignition of cotton waste on the unexposed side for a period of time equivalent to the fire resistance rating required'of the barrier; The temperature levels recorded on the unexposed side of the fire barrier are analyzed and demonstrable that the maximum temperature does not exceed 139 *C [250 *F] above ambient; and The fire barrier remains intact and does not allow projection of water beyond the unexposed surface during the hose stream tests (for acceptable hose stream test methods and time of application - See Section VII.)
If the above criteria are met for fire barrier walls, floors, ceilings lIidd fsejtaridiiipj thesamefirea@rea,the'barrierisconsideredtobeacceptable.pmehtiehcl65uYesse NRC fire protection guidance also ensures that door and ventilation openings e
and penetrations are properly protected.
The_ guidance requires that these openings be protected with fire doors and fire dampers which have been fire tested and listed by a nationally recognized testing laboratory (e.g.,
Underwriters Laboratories or Factory Mutual).
In addition, the construction and installation techniques for door and ventilation openings and other penetrations through these fire barriers should be appropriately ' qualified by.
fire resistive testing.
The guidance of NFPA 251 and ASTM E-Il9 should be consulted with regard to construction, materials, workmanship, and details such as dimensions of parts, and the size of the specimen (s) to be tested.
In addition, NFPA 251 and-
,m t
e A.
S ASTM E-119:should be consulted with regard to the. placement of thermocouples on the specimen, t
V.
'FIRETENDORANC @ ESTINGIXttEPTANCEICRITERIX?FOR (Staff) ELECTRICAL RACEWAY ~AND~ COMPONENT FIRE BARRIER' SYSTEMS"FOR SEPARATING 1 SAFE SHVTDOWN FUNCTIONS WITHIN THE SAME FIRE AREA The NRC provided guidance in Appendix A to Branch Technical: Position 9.'5-1, Position D.3. (d)', - for cable tray fire barriers.: This fire protection' guidance:
states that the design of fire barriers for horizontal and vertical cable' trays should, as a minimum, meet the requirements of ASTM E-Il9,," Fire' Test ofm Building Construction and Materials," including hose stream test:. ' On.
November 19, 1980, the NRC issued Appendix R to 10 CFR 50.. The technical-basis for Section III.H, " Fire Barrier Penetration Seal Qualification," states; that " Fire barriers are ' rated' for fire resistance by being' exposed to a'
' standard. test fire.' This standard test fire is defined by the-American-Society of Testing and Materials in ASTM E-119."- In addition, this technical basis stated that "If specific plant conditions preclude the installation of a' 3-hour fire barrier to separate the redundant trains, a 1-hour. fire.ba_rrier and automatic fire suppression and detection system for each redundant train will be considered the equivalent of a 3-hour barrier." Apps6diERith7101CFR PaFliSO$55EtionsIIKGMFifeI6?6fhMi6nTbfEi~sfs"shiitd6siDcapabilitF ^sifs prov i de s,4wh ats the t NRCMi dwsYa$equ i valent? me adUfo rlen 5 hr i ng"st hats obsi shutdowni rain}js]freeloMi[ejdasagej "(WihstonTHd'StEiish)~
~ ~~7 ~ ~ ' ~
t In 1984 Appendix R' workshops held with industry, and later in GL 86-10, the staff provided guidance related' to fire barrier designs for raceways.
In, " Question and Answers," to this GL,' Question 3.2.1., " Acceptance Criteria," the staff provided guidance on the cold side ~ temperature for fire-barrier cable tray wraps.
In response to this question the staff stated that-the acceptance criteria cont'ained in Chapter 7 of NFPA 251, " Standard Methods of Fire Tests of Building Construction and Haterials," pertaining to'non-
~
bearing fire barriers was applicable to cable tray fire barrier wraps.
Chapter 5 of NFPA 251 explains the conduct'of the fire test.
The following is the NFPA 251 acceptance criteria:
The wall or partition shall have withstood the fire endurance test without the passage of flame or gases hot-enough to ignite cotton waste, for a period equal to that for which classification is desired; The wall or partition shall have withstood the fire and hose stream test as specified in Chapter 5, without passage of flame, or gases-hot enough to ignite cotton waste, or of the hose stream. The assembly shall be considered to have failed the hose stream test-if an opening develops and permits projection of water from the stream beyond the unexposed surface during the hose stream test; and Transmission of heat through the wall or partition during the fire i
endurance test shall not have been such as.to raise the temperature
y e-
, on its unexposed surface more than A139 *C [250 *F] above its initial temperature.
matiFinlFIppliedsdifiEf1Hf6?iWsEsissy~ qualification test.'f6FNiifhT*iseEessful The staff considers the fire endurance SIFFisi
- oETE6sp~66FnE(staff)"f6*bi i f " t Wf 011 owEg~ci6d i tTon s"iFi^5E fi~
~ ~ ~ ~ ~ ~
The siTaFijiT65isp6sid7Iidi (Staff) terperature of'the fire barrier systis^,PasVisiiurid'^6h"theexteriorsurfaceofthebli (Philadelphia Electric) cable tray, raceway, or compone(Qjdsl _nt,'di~d no exceed 139 *C [250 *F] above its initial temperature; iiid (Staff Guidance: NFPA 251 and ASTM E119 allow this temperature to be determined by averaging thermocouple temperature readings..For the purposes of this criterion, thermocouple averaging can be used provided similar series of;thermocouples (e.g., cable tray side rail) are averaged together to determine temperature performance of the raceway fire barrier system.
In addition, the conditions of-acceptance are also placed on the temperatures measured by a. single-thermocouple..Under the conditions of acceptance, if any single thermocouple exceeds 30 percent of the maximum allowable temperature rise (i.e., 139 *C + 42 *C - 181 *F [250 *F + 75 *F - 325 *F] the-test is considered to have exceeded the criteria temperature limit.)L IFF5ip6Et'iilbIiffth5 Mniijiosidif fds?idihpiFifEFE!InilifdOFfihy'[thisif.i Fi tes'sifghablesisFsincludedsiniths3firsibarrishtestspbcim'enf ^
t g g g g g gg g gyg y n. E EE~Eff 8 8 7 7 HsG*al"inspiEtio'n of I
the cables is required. Cables when inspected 'shall not. show signs of degraded conditions' resulting from the.thermaliaffects of the fire exposure; and (Staff Guidance:.For those cases where signs of thermal degradation -
to the cables is present, it is considered that the Eicisiy (Phil.
Elect) fire barrier did not perform its intended firi7biistive function.
For those barriers which are not capable of performing their intended function, a deviation based on demonstrating that the functionality of thermally degraded cables was maintained and that these cables would have adequately performed their intended function during and after a postulated fire exposure may be granted. The.
i 3 When the temperature criteria is exceeded dEh6fnp6ne6t?diinI@yWiciifs' (Staff), component operability at the temperature 3 hdit'ishi~aigser1I6Eid'6y
~~
the component during the fire test EustVii'isissd (Staff).. That is, raceway s
fire endurance tests that are judged accepfable on the basis of a visual inspection of certain components may not be applied to other components without a specific evaluation.
' Examples of thermal cable degradation are: jacket swelling, splitting, cracking, blistered, melted, or discoloration; shield exposed; conductor insulation exposed, degraded, or discolored; bare copper conductor exposed.
g~
r e
e
[
L attachment to this position'provides a suggested methodology for-demonstrating the functionality of safe shutdown cabling during and.
after a fire test exposure. Ths41Trp65s!6fithiffichisiendia f66Efl60slifyitdifshifft6Miisti fMobseNedWesTiti onsii ntfi fi :
ba FElerppdrformanceiO For%sngi nesFinbanilysiikjusti f91 ng nnteri testednithbutidabissMsV fl ee 9 bani en tempetstuFe M ohdi ti onM g reate r3 th ania116wed R eanibs~" '
hased iodiaMmp ari s onY o Eth eff;i rbnarf f erli h te Fn allt'einpe rat u re
~~
' rofileMessrediduF16ptheifire fendura6cnt'estLtdeilstingYea6Ts' p
sp eci..ficipeFfopnp@$j a{aMucgasle nji ronme,n tjKiujlifi c a tjh]((
tests 2 (Stiff)
The cable tray, raceway, or component fire barrier system shall. have:
remained intact during the fire exposure and water hose. stream test without developing any openings through which the cable tray, raceway, or component (e.g., cables) is visible.
Section VII identifies acceptable hose stream test methods and the' time of application.
The test specimen shall be representative of the construction for which the fire rating is desired, as to materials, workmanship, and details such as dimensions of parts, and shall be built under representative conditions.-
Raceway fire barrier systems being subjected to. qualification fire endurance
. testing should be representative of the end use. For example, if it is intended to install a cable tray fire barrier system.in the plant without protecting the cable tray supports, then the test program should duplicate these field conditions.
In addition, the fire testing program should-encompass 6F/bbbnd raceway sizes an( the various configurations for those fire barrier sylisifii~i6 stalled in'the plant. It should be noted that several test-specimens will be required in order to qualify various sizes of horizontal and vertical runs of cable trays and conduits, junction boxes and pull boxes, etc.
The cable tray or raceway design used for testing should be ' constructed with materials and configurations representative of in plant conditions ;{e.g., irs the IffEablesf mass associated with typical steel conduits and cable trays)blisishallibe" included?iniths?fisisayffiF#7biFrisEtss t7spici'iiienMihsief ca t
regresent3tjvelof thegn, stalled 31antispecjifijcjcablesi (Stafff'
~ ~~
^
3 Measuring cable temperatures is not considered a reliable means for determining excessive temperature conditions which may occur at any point along the length of the cable during the fire test.
In lieu of measuring the unexposed surface temperature of the fire barrier test specimen, methods which will adequately measure the surface temperature' of the raceway (e.g., exterior of the conduit, side rails of cable trays, bottom and top of cable tray surfaces, junction box external surfaces) can be considered as equivalent if -
the raceway components used to construct the fire test specimen represent plant specific components and configurations. The metal surfaces of the raceway, under fire test conditions, exhibit good thermal conductivity l
properties. Temperatures measured on these surfaces provide a conservative indication of the actual temperature rise within the fire barrier system.
In? l9795MsfidihDidcTsiRInsu FsFsRANIEissbid ?hEfiFi?shd6FsWEsTlist%th6d fodra ce@agf,igbarrMysyjpmpfggj nsura.pphirpospl[ Jig [me thpd dhf e
p
' EnduFihEVEPFotEt T ViiE5VelifeJSystiiniff6FfClIss3ETEl set Fical' Ci rhui fs ?
specifiedithatf(A5EFiciH3scliar IhiufeFiT^Esbli~tiiihirafures'be'mohitofed by.
7 th~ermbe6dplisI Industry considers this the proper location for determining -
the temperature rise within the raceway fire barrier system. 'Since' cable Jackets have a low thermal conductivity, the' actual -local ~ temperatures of the cable jackets indications of barrier failure, and internal fire' barrier -
temperature rise conditions during the fire exposure are masked. fMonitoring.
cable temperatures can.give indications of low. internal fire barrier temperature conditions during the fire endurance test..Using'this temperature monitoring approach, cable damage can occur without indication of excessive temperatures on the cables. This linked with no loss-of circuit-integrity would give indications of a successful test.
The staff considers; monitoring _
the cable temperature as the primary means of determining cable tray or raceway fire barrier
~
Therefore, the7sfiff hasiinc6F56Fitsdsthe* performance to be nonconservative.proVii1oW[f6EiGFstifi cabl esithatfard si ns t al l ed tin f fi rei b arri sri testispec imens i As d i s de siEd ~ibovi7 t'impdFstiiFis'seWi tseid~os~thi"bx tiri 6F~ su r( STAF F) :
~
face of the raceway provide a more representative indication of fire barrier performance.
FiFi?ahdEFiiiieTthifl6gT6f?FiEssiyffife?#iFFiFrnistihis?should 'be with6ut.
cablesn:1Thishmethod>1sipreferredlbecauseibtexcludingicables from theLtest-s' pecimen?:it'sliminitesibiasisinEthsstbst? results?creatediby: the thermalTmass?6f thetcsblisMWithoutithisythersalfmass8thlelint~ernalltesperature conditions
^~
measuredibystheYtest(specimen;thermocouplesiduring'theTfire' exposure wilf p rovi delai mo relicdu rateide te rji n at ios o Gfi &b a rri egthe rmals pe r fo rmanc E; (TVA)
Thermocouple Placement - Test Specimens Containino Cables-The following are acceptable placements of thermocouples for determining the thermal performance of raceway or cable tray fire barrier systems that contain cables during the fire exposure:
Conduits - The temperature rise on the unexposed surface of-a_ fire barrier system installed on a conduit shall be measured by placing the thermocouples every 152 mm [6-inches]5 on the exterior conduit surface underneath the fire barrier material.
lWilthefs666dplisishall! bs it t abbeditFithe?sitiff 6Ef 66ddi t"suffde il oes te'd Toppo's i tefo f) th edist deckisnd; closssttto?the(furnaceiff rendurceh JThermocouple's?shall%alsd be lplic sd Mmmedi atelyla dj sden,t i t o@jsj rjuctural@embe rs gs upp o rt shan d barrieNpenetrationsj (TVA)
Cable Trays - The temperature rise on the unexposed surface of a fire barrier system installed on a cable tray shall be measured by placing the thermocouples on the exterior surface of the tray side rails between the cable tray side rail and the fire barrier material.
In addition to.
placing thermocouples on the side rails, thermocouples shall be attached msTEFHKsH6sisE6EsidisFilistilTidf65723EffEffs?TEibisTtFsy%si'deifFii isd bare [c6ppyricondu cto rsMa3131 man [M i nchtj n s t av ati on[tol e gncM acceptibleg (Entergy Operations)
.o
. _g.
to two I" gage AWGT8TitFihdsd7(TVA) bare copper conductors..The first-copper conductoFWill^bi"init311ed on the bottom of the cable-tray rungs along the entire length ind"d6sdithEl"6siitsdfhsKdi6tiF](TVA) of the cable tray run. The sec5hd^c6hd6Efor"shall'hi' inst'illid along the outer-top surface of the cables closest to the top and towards the center of the fire barrier. The bare copper wire is more responsive, than cable jackets, to temperature rise within the fire barrier. enclosure. The temperature changes measured along the bare copper conductors provide indication of joint failure or' material burn through. conditions.
Thermocouples shall be placed every 152 mm [s 6Fth5]/cibTs~tfiy side 6 inches ddwh?fhi 16h'itudinil?id.stiMalong the 60tsi.ds?sHFfic. ?
.y.
Eli2sdElitsidfate;1MdfiEink) tF~3]MtrHEtj[slJmejnbersMsupportsnand"'
bartierpenetrathnsj(TVA JuREtiBHFB6kss?(JB)I9?Thi?fejspsFitifs?Ffsi?6ETtKeTEsiipsiidTiuffi24t3Ci ftpef barfisrnystemsihstalledsonluhetion boxesfihalltbefineasurediby~
pl aci ngithe rmo'coupinion t e i th e rith e Ti niide20t itheX ou tsi dei o fre a ch1J B surfaceh TEsch7JBissifad5WrAfahe?shalllihave15fminimumioffoni ~ ^ '
the rmoc 6upl e M oc s ted patd ts ! g eosstriedent e@is qu'a Fel f60 In9additionM6HE t h ermoebupl eisha1 E bet in s t all ed ifors e ssrf ohe
~
area n iTheseTthersocosplesishall! beflobatediatstheQeomet ricMestersTof ths? one fsqbsFs? foot hress : tat 31easti oneitherhiddos
~
~ l_ac. ed_!within.s,_25d_,[_14 i_'nch].Vofsf_each@_ene_tra. tio_nic_pl onne_' torti._n.ter_'facil P
c
~
m-m Ai Fdr6pIMT6E?iWfiinilSW1 EdF6pitiiddiFitEFis?ihilMbiTsiliUFid iby tharmoc6Uplesiblacedieseryll52 mm*[1241nchis][ontthessbles90uted -
ki thint the7airf drori"andJ byWstranded ? AWG f 8 dblareicopper 8 conductorWo6fid -
i ns i deTshd TaTo ng1t h efsh t i rsh l engthW fi the f ii Fdropisys tsm1 wi th~ ~~~~' " ' "
t h ermoccupl esii n s til l sd[ eve rW152 ismi[62i n chs s)!al ong t th'sM e nythT6fTihi coppe@onductoWghe/coppericon' ductor?shallibelin?closelp bxisityTwith; p
theibnexposedsidrficWoftthetfire*barrierimaferil'all fTher'mo~ccuplestshall also1belplaced pen.etrat f ons; /"immedistelysaajacent?tosilpuppirtjsjagdjtdfrier"~~ "
i (Staff) in addition, thermccouple: : hall be placed every 30',m [12 inche:] cn the surface of the cutee-esbk: nearc;t to the raceway and on the -
wrface Of the cable nearest to the undcr:ide of the 10 of the fire barrier. Wi th$ths?Eis sh t'i6hfiffii rdFobE?thsifhifal lit li ddio f the'Fnio Eospl es? 6nVcabl e ss i sl optibn al s and ti sil e fts toltheid ishre tiBHF6fst he l i c bns ssh tes t isponso rd o r$ tes til a bopa tdry MC a bl e ith e rniocoUpl esiiFei to "
be? usedsfoMenbineering;puFposessonlya LCableithesiocouplesi albniare ~
not; adeeritablsi f6r!the ~demonitFationf 6fhfireltdrrieriperformanceiT" HowsV6 ry cabl e1thehnocodpl ejn.ayjs spport M rMa rri eddeji aMof '~
con #tionse(TVA)
Temperature conditions.on the unexposed surface of the fire barrier material during the fire test will be determined by averaging the temperatures measured by the thermocouples.
In determining these cable tray or raceway temperature conditions, the thermocouples measuring similar fire barrier areas of.
performance shall be averaged together and the basis of acceptance will be
z a-
. based on the' individual averages. -The following method of ~ averaging shall' be followed:
%nduits - The thermocouples applied to the outside' metal surface of the conduit shall be averaged.together.
Cable Trays - The thermocouples on each cable tray side rail-shall' be-averaged separately.
For example, thermocouples placed on_one' side. rail will be averaged separately from the other side rail. -In addition, the temperature conditions measured by thermocouples on the-two bare copper conductors shall be averaged separately.
Gebk :
The thermccouple: used to me;;ure individual cable t+mperaturc; will be u:cd-for engineering purpc;c: and -:kll not be a:cd-f+e evaluating the performance of the fire barrier system.)
ihiWEt i 66" B6 sis?MF6FsssilTFJBsNEishTlsysT66FBnsithiB6s60pl s111dsd onTeachs08:surfice itheiindividualiJBisuFfice1thermocouples?shalllbe '
^
~ laced foEe'gethbri,goMargeridBsf whithihavsimore" thatrachAlB?s ass' raged?to' oneithirmscos ls p
spfacesks!1plybgaveraged(tpgetheff ~p~~~~^"
~ ~ ~~
Ai FdfossEThs?thsE6E6051ss?TiliE^id766{thi"66fiFIdsbl s(sF~F66tbd ?ihTihe.
.ai rd.ropa fi re !barrierEs. h'a.l.l.i.b..siav. ersied_2tdg_sth_eW_ (Staf f)
~ ~ ~
The averages of any thermocouple group shall not exceed 139 *C'[250 *F] above the unexposed side temperature within the fire barrier test specimen at the onset of the fire endurance test.
-In. addition, the temperature of each individual thermocouple will be evaluated.
Individual thermocouple conditions shall not exceed the 139 *C [250 *F] temperature rise by more.than 30 percent.
Them6660~61FIplI65ishtSTsiF55*6Eiii#EsNith56f4S61bi (TVA and NUMARC)
TheIfol16Wfni?iFiiiEiipliS1 E"iEEFEBE60pl E11IEsEhisifdF20EtiFiihi&ifthi -
themalf performance @fjacswihodabl eltraygijelbafrierisystemsithatid6(n6C contajnicableg c6Edif OsPETfietitispsFif0Fi?Flss76 fM6s~Ehiiiidssd OsHEtiEF"oEi?fiFs i
ba rri e h3ys tem 4i ns tal Ted Walconduitishal l i beime as ureds by(pl ae inf thermocbuplesieQsrfl52immf63 inches!oh?thePixtsfioEc6hduiinurfidi betWssristheicbndditiandithe[unekp6ss]disurfabssofsth'sjfirsf 6anief ~~~7 f
materi al b'?Th eiss th e rnicioupl e s y sh al l? beVatt achudit o ith sib (ice surfsceiosp6sitefaf3theitestideckfahd(closestitbtth5(fdrh scheced ThelintesaWideWafit empepainfe Ushall? bsMsasifrediby?i stFandedfAWG T81 bire?cepper: cond6ctors routedithF6ughjtMsnti re11 snif6?BY the conduitssystsinithitherindsbupleninst~alled n
hl osgithed ength! o ff thsR6ppMonductsWsThefs(sverydR@en4641nc oc6uples hallEAlsolbe barrieglpeget[at,1ongg(jplacedQmmediateli 3d aceptitoialj M tt @ al semb Cabl,esT~ ray.,.-,Th,et temperat -.- lselonith_elunexposed-,csu fa_c.,o, Nns ? fire.,
n bsr[jg@ys,N @sjallg($($g$Qls}(($/ish, al]Jejmpa,jgedibyjpJ,M@g s
ure r
ev tg
w e thEFW6E6DyTWiiisFD5CnE 611EEhss1?65'~thirikGF16EEErficheid(TsaDi trayisidefrails3betkeeMthe]ls'idefrhilhnditheiffFelba'rrier matepialM
~
InteFhal$acewayitempefst0pissshAlljbs[mekss' edlbh a' stranded? AWG!8iliiFs r
EopperM06ddetoriroutsdl6n3theltopiofsthsfdableltrayfrungsDalengithe ~ ^
sntirellength?and[downithnlong'itudissifsente#df?theicablet traylrus.
wi t hit he rmocodpl es B h s tillidisvsryM52 M[6dipl a ced : immed i a t thsiEbppeniconductorMThnm6c60pleHshillg ppjjcenj((diall3 ty jts fl yemyed @ jppbrp [fpy ga pier penetrit;iin~Q 3dHEEfBW2B5EiWQs)PThiitispiFif6FEiflisW6?lhiTUnikpbsed 'sUFfidsT5ffi-firsibirfieMiys.teminstalledsonijuhetibh!bbisinhall be measursd bf"~
placingsthermocouplestbnieitherithe?inside?ostijetsutside of each48 surfabe% [EschNBssurfadifoFifidelshalll#Welsfhihimum' of ~one " ~~'
therm 6cbup1phloditsdiatditsdeometFid?cintef%llhfaddition, BEE therm 6coupleishallsbslihstalledIfodsviryNnelsduaFe foot of JBishFfsEs seesdnessitheFinbo0hleshhalbbes16Eatidisteth'e? geometric centers of
^
thejonefsqdafstfd6tnFessMAtsisAstidn p;,lssedwwmm.hinf25Ahv A[uhrwo-swy]Tofieas.voua ps$theHnoedusle isit ffnm3 lWinch chi nstration { c.wo -
..a +rw..v; vh.e,aww w4Av.o nn e c t o r/ i n t e rfac ii ue sm u.
e r wMcA
%vo.&#w AiFdF6)YMThiTGfiFKillTifFdF5p7taEpsfiGFissibilUbs measured'bysi htranded?AWG183baisMopheFMhnductor??outeddinside"andalongthe..entTri length 1bftthalairdrdinsysti$sithithkrinoceufliMinstalled every'rq52fmm condustorM]fal6np the*lengthief$ths loppe Mconductork The coppehal
[6Einches fire!baFrieE materisil iThsFm6ccupissCshalkalso bes laced ;immediately ^
adjaceht{tga}Djppgrts@p({p{nyMatipps['
j "p~ ' ~
~'
' ~ ~ ~
Tempi (it0FET66dftl6 hit 6H3YhEf6Eiip6TidfiUFfiEis%fTihiffi FefbifrieFma fsFiill d uri ngi t ha ifi Fsites tt wil l? be idet brmi nsd !bj f a ve rig i ng Ethsit'empe ra t u re s j me as u ped by thelthermocouplessidstal.ithermodb{uples7measuringtilmilarcareasnofithe lsdfinibF onithA Miceway C in# determining (thesd teinperaturstbonditionskthe barrierlshallibeLaveFagedit6gstheMMcceptanssTsilRbeibasedion the
" ' ' ~
i ndi vi d0aljaversgeMhslfpil owi sgjethbdichape}sgipKshalli beifollisid[
Cdnddifi%ThhlthTFhdE6dplss33phliid46Tihi?6sfildi7iiietaf'ibffide"6f7ths conduigsliallitielajerag;ed[torjethg"'~~~'" ~ ~ ' ~ ~ ^ ~ ^ ~
CibTsETFsysMTh'F36Edif66bb)1EiT6His5E6fEibliTffsy?sfdeNiil?ihall?Si averaged ssepaFhtelyO FoNexajnpl e $ thermocos wfi l s be 4 averaged l sepapatelyffrom ;the %t hem ide tonithalbare
' er coQctgpijhallAMavssgidMepjrately[f@(theMideMils[gopp~
3dnEtiohTBdiis$ifEFX1Bs7thifUiiEBhlyTE6EithiF562E6ETeidareaE6"JB surfadepthelindividualf dB3urficeEthermocou' les%hsllE beMeraged~
p togetherEFbnNBs:1thatlhive2msreithattone?thermocoupinchleachSB surfac'e/theftherm6cohpjsRonitheyndi idua@B;surfacesjshallibe"
.averageditogeped j
aifdropjpfRbarliehishalMeta;vera$d[togethef"~ ~~~~ ~ ~~'
.t i
w
'O' O
i Th6faVifijs76f"X697thiFin5E60preigFiub?sEillT66tZiEsidII39? "C?[k 5C*F)?ib6VE z u
~
the unexposed! side tsmperatsreswithin?theifire%hreieWte'tispecimsniat ths" s
t oriseticff thMfirstenddranceitsst2 lIn{ addit 16nhtheitenseratureioff each~'^
individuilEthermoc40pleswil1%e? evalsatedOIndhidda s h alls notlexheed1thes139MQ250jiFJitempststpfelyj se}hthermocospl ed condi bylmoreithagj30 der _ centi I f?iT fi Fs? 6EFFisFTt.isGEEEissiWII635t*Eibi sFd6si!K5t7sisEtEdissaisy~s?bF ma ximurFsingl e ipo in t s teinpe ra t drescri t eH ip:t herstheli nte rn anraceway
~
temperatsreiprofile?isimeas'uredlbytthe^1nstrdmehtedibarefcopperscond6 du r.i ng i t he Afi re texpbiuFe ican ibe f bseditos as sE s s Tc abl s L fun cti o n sl i ty"th ro ug~h ? siF ove nit es tj nglo fipl.an t9peci ficj ablei,typ s s ; an.dison stpucti on.) ~~
~ ~~
VI.
HOSE STREAM TESTING NFPA 251 and ASTM E-Il9 allow flexibility in hose stream testing. The standards allow the hose stream test to be performed on a duplicate test specimen subjected to a fire endurance test for a period equal to one-half of that indicated as the fire resistance rating, but not for more than 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> (e.g., 30 minute fire exposure to qualify a 1-hour fire rated barrier).
For safe shutdown related fire barrier systems FifEEihisdTih?Ss'Efl6EIViisd dspl i difslellsetEiEilNa blil EFiffoE EsEisa.BahFc ompo nen t? fi ret b a rri e 6 tes t the staff]thatihaVe beenSexposedito2th~e'd-durationLtestTfire exp6sure(Staff),
specime~ns fi ndT t hs" ho si~it riam~ippl i chfi 6E' ipisi fi ed ' 6)^1hs'N F PA~ 251 acceptable.
NFPA 251 requires the stream of water to be delivered through a 6.4 cm [2%-inch] hose discharging through a standard 2.9 cm [1%-inch] playpipe nozzle onto the test specimen after the fire exposure test. The stream is applied with the nozzle orifice positioned 6.1 meters [20 feet) away from the center of the test specimen at a pressure of 207 kPa [30 psi, gauge)..The application of the stream is to all exposed parts of the specimen for a minimum duration of I minute for a 1-hour barrier and 2% minutes for a 3-hour barrier.
As an alternate forldl5Effica1956swijdiFe!6iiWiirHE5fiipedfhins?(Staff),
the application Bi^thi~hdie~stFsiin"tesFEiETslirf6F5ed^immsdiat'eTy after the-completion of the full fire endurance test period.
If~this method is used to satisfy the hose stream testing criteria, the following hose stream applications are considered acceptable:
The stream applied at random to all exposed surfaces of the. test specimen through a 6.4 cm [24-inch] national standard playpipe with a 2.9 cm [1%-inch] orifice at a pressure of 207 kPa [30 psi]
at a j
distance of 6.1 meters [20 feet) from the specimen, (Duration of the hose stream application - 1 minute for a 1-hour barrier and 2 minutes for a 3-hour barrier); or The stream applied at random to all exposed surfaces of the test specimen through a 3.8 cm [1)-inch] fog nozzle set at a discharge angle of 30 degrees with a nozzle pressure of 517 kPa [75 psi] and a minimum discharge of 2841pm [75 gpm] with the tip of the nozzle at a maximum of 1.5 meters [5 feet] from the test specimen. -(Duration
- Q[
..Q -
t E of the hose stream application - 5 minutes for'both 1-hour and 3-hour. barriers); or The stream applied at random to all' exposed surfaces of the test specimen through 3.8-cm [1%-inch] fog nozzleiset at a discharge angle of 15 degrees'with a nozzle pressure of 517 kPa [75 psi] and a.
minimum discharge of 2841pm [75 gpm] with the tip of the nozzle at1 a maximum of 3 meters (10 feet] from the test specimen.. (Duration-of the hose stream application - 5 minutes for both_l-hour and 3-hour barriers.)
VII.
FIRE BARRIER COMBUSTIBILITY The NRC's fire protection guidelines and requirements establish the need for each nuclear power plant to perform a plant-specific fire hazard analysis.
The fire hazard analysis shall consider the potential for' in-situ and transient fire hazards and combustibles. With respect to building materials-(e.g., cable insulation and jackets,-' plastics, thermal insulation, fire barrier materials), the combustibility, ease of ignition, and flame spread over the surface of a material shall be considered by the fire hazards analysis. One method of determining combustibility is by subjecting a sample of the fire Darrier material to a small scale vertical tube furnace as described by ASTM E-136. The flashover ignition temperature sfMhiliiiatV?ill (as determined by ASTM-D1929) and the flame spread-characteriificinfithe~'
matsriil (as determined by ASTM E-84) cf the fire barrier materi;fshI1Tils6 be"eia16ated. The potential heat release of the material :(iifdst~eFirii6'edibi ~
ASTMiD2328FsDFPAf259)} shall also be detcrained and factoFid'inf6^the^ fire -
hazAidi~inal~ysil.~ 'ThEhcot release cf the materici can be determined by tet-ing to the provi:ica; cf ASTM-0 3285 cr UFM 2597 Fire barrier materials used as radiant energy heat shields inside containment and used to achieve a combustible free zone are required-to be noncombustible-as defined in Section III.
VIII. REFERENCES Nuclear Reaulatory Commission 1.
May 1, 1976 Branch Technical Position (APCSB) 9.5-1, " Fire Protection Program."
2.
February 24, 1977 Appendix A to the Branch-Technical Position APCSB 9.5-1, " Guidelines for Fire Protection for Nuclear Power Plants Docketed Prior to July 1, 1976."
3.
February 19, 1981 10 CFR 50.48, " Fire protection."
4.
February 19, 1981 Appendix R to 10 CFR 50, " Fire Protection for Nuclear Power Plants."
.o; 7
6 -
5.
February 20, 1981
" Staff Position, : Safe Shutdown capability,"
6.
July 1981
'NUREG - 0800,-Standard Review Plan.(SRP), 9.5.1,
" Fire Protection for Nuclear Power Plants."
?
l i
r I
g pt p- <
7.
October 19,_1983 "NRC Positions on Certain' Requirements of:
Appendix R to 10 CFR 50," -(Generic Letter-83-33).
- 8.
April 24, 1986
" Implementation of Fire Protection..
Requirements," (Generic Letter 86-10).
American Society for Testino and Materials 1.
ASTM E-84 Test " Surface Burning Characteristics of Building Materials."
2.
ASTM E-Il9, " Fire Test of Building Construction and Materials."
3.
ASTM E-136, " Behavior of Materials in a Vertical Tube Furnace at 750*C."
4.
ASTM D-1929, " Test Method for Ignition Properties of Plastics."'
5.
ASTM D-3286, " Test Method for Gross Calorific Value-of Solid Fuel by the Isothermal-Jacket Bomb Calorimeter."
3 American Nuclear Insurers (ANI) 1.
July 1979, ANI Information Bulletin No. 5 (79) test criteria for " Fire
- Endurance-Protective Envelope Systems for Class IE Electrical Circuits."
National Fire Protection Association (NFPA) 1.
NFPA 251, " Standard Methods of Fire Tests of Building Construction and Materials."
2.
NFPA 259, " Standard Test Method for Potential Heat of Building Materials."
P t
[ Filename: G:\\GL8610PC\\ CRITERIA.PC2]
.f 5
6
lW
+
l 72 9,
@;ol N
n Y
<x y
11 iATTACHMENTJ K
. ACCEPTABLE METHODS FOR.DEMONSTRATINL FUNCTIONALIl1 0Fu
[.[
CABLES' PROTECTED BY~ RACEWAY FIRE BARRIER SYSTEMS
'~
DURING'AND AFTER FIRE ENDURANCE TEST. EXPOSURE-I.
INTRODUCTION The NRC considers fire barrier systems, which meet the acceptance
~
criteria, adequate under NRC fire. protection regulations 4 Thellicensee.
where the criteria are not met, can submit lan engineering analysis to t the staff that clearly demonstrates the functionality of.the protected.
cables.
This engineering analysis should' consider the cableLinsulation type, actual voltage and current conditions, cable ~ function, and thermal '
affects on the cable.and.its ability to function.
This evaluation"shalli also consider cable operating temperatures within the fire barrier at the onset of the fire exposure.
II.
CABLE CIRCUIT INTEGRITY TESTING ANI Criteria In 1979, American Nuclear Insurers. (ANI) issued 'a fire-endurance test method for raceway fire barrier systems foEHKisMdds4EFpas"es.' This
. method, " Fire Endurance Protective Enve16pi^$'istims"for"Clii5~IE7 Electrical Circuits," specifled a circuit integrity test. The intent of this test was to identify the onset of fire damage to:the cables ^ within.
the raceway fire barrier test specimen during the fire endurance test period. The circuit integrity test voltage is 8 to 10-volts DC; therefore the loss of circuit: integrity under these-voltage conditions may only occur as a result of a dead lshort or open circuit.
During actual fire testing: conditions 'of raceway fire barrier systems -
T thermal damage to the ' cables has resulted. This thermal' damage _ has led:
to cable jacket and insulation: degradation without:the loss of. circuit integrity as monitored using ANI criteria. Since cable' voltages used for ANI circuit integrity testing do.not replicate cable operating voltages, loss of cable insulation conditions can exist-durin'g the fire -
test without a dead short occurring.
It is expected that if the cables.
were at rated power and current a fault would propagate. The use of-circuit integrity monitoring during<the fire' endurance. test is'not' considered a valid ' method 'for demonstrating that the. protected shutdown-circuits are capable of performing their gquired function during ~sFid and' after the test fire exposure.
ThiFif6 Fin c t(Ehi tMstiiF;i;tystiiiah t t
$66ti?shki'fiditE7ssti quallficatlog (NUMARC)'lff3RC3]ceptinggiprlaIfo@fjfsjgafgjef~
IIlkil@lPMENTIOUACIFICATION C$ispsiFiiBEinfi thiEfFeliFFisEBEGFHilst 1ssi TaYUFi?pFofHs mea su r'edidd rin@{thiM@lendeineit e stito fex pg? cable pfoFliliiEs-dat'a$such3MdatsifromienVirdnmentilfqbaliff AtfonI(EQ)lt@estihQ~could heJproppeditpithepta[((aightMdifgQej$ongatjngicjblj~~~
"~
b J
e i~
O-9 k
1 i fii6"ctT6sil ft'yETEQitiillh54 fit}JfsillyIfiEfsfiiidIt'6Tf4#Ms senditf 6nsninc16dihg1ratadivoltassFandicurrentMByrdorfelitIH thesEQitestidataiwonid@b6d Jdf/$testydataifoWmanifesblutypMsi ssidelaMablshsebhantim?toienshrelisable ~~~
fUnEtionaliti G A91 kgel todayM Ussf of!EQ?dataithusdeptesentdaMostleffective 32E ffd img i{s y ceeJed[ f^fo dfire?tisting ~if W th'o
' ddressicablePfunctionallt
~ ~ " - " ~ kesth'd.
ases%h a
~ ~ ~ -
~" ~
1FE75fifKigfisi!DiifiW6iipiHYiri~dQ@i?ifisKtiliip3lfif0?iTpf6fHillf3 existingiEQrandiLOCA test:resultsForvair7oventte' tiresultstihan s
acbep*abl'ed pp?sii ndo rporat esn thEan ti ci pA t ed{ tem;p era rda chWo ldemons t ra tefcsbl e ?functi on al ity f pfondek tlis subjeht;anklys selfthsatiniteffects re'sul_tf{NUMARC)~ify~instillsdipowericablsshwithitheffiveltsst' ~
~ " ~ ~ ~
~^~~~~~~~'~~~P~~~
IV.
CABLE INSULATION TESTING The two principal materials used as cable insulation.and cable jackets by the nuclear industry are thermoplastics.and thermosetting polymeric materials. A thermoplastic material can be softened and resoftened by.
heating and reheating. Conversely, thermosetting cable insulation materials' cure by chemical reaction and do not soften when heated.
Under excessive heating thermosetting insulation becomes stiff 1and brittle. Electrical faults may be caused by softening and flowing of thermoplastic insulating materials at temperatures as low as 149 *C
[300 *F).
Thermosetting electrical conductor insulation materials usually retain their electrical properties under short-term exposures. to temperatures as high as 260 *C [500 *F).
Insulation resistance (Megger) testing provides an indication of the condition of the cable insulation resistance, whereas the high potential (Hi-Pot) test provides assurance that the cable has sufficient dielectric strength to withstand the applied rated voltage. A cable insulation failure usually results from two breakdown modes: one failure mode is excessive dielectric loss which is due to low insulation resistance, and the other failure mode is overpotential stress which is due to loss of dielectric strength of the insulation material.
If Megger tests are not performed at frequent intervals during the fire exposure, indications of insulation damage in insulation may go undetected.
Insulation, when removed from elevated temperatures will reset. Megger testing of insulated cables after the lire endurance test and after the cable has sufficiently cooled may net detect degradation in the insulation resistance. Therefore, wet or dry Megger of' cables after a fire exposure does not provide reasonable assurance -that the cables would have functioned as intended during the fire exposure.
To provide reasonable assurance that the cables would have functioned during and after the fire exposure, Megger tests need to be performed before the fire test, at multiple time intervals during the fire -
exposure (i.e, every 20 minutes during the 1-bour fire test and every hour during the 3-hour fire test) for instrumentation cables only, and
y
, after fire endurance test to assess the' cable insulation resistance levels. This testing will assure that the cables will maintain sufficient insulation resistance levels necessary fo~r. proper. operation, of instruments.
The Megger tests (pre-fire, during the fire [if perf armed), and immediately after the fire test conditions)'should be'done; conductor-to-conductor for multi-conductor and conductor-to-ground for all_ cables.,
The minimum acceptable insulation resistance-(IR)' value, using the test voltage values as shown in the table below, ic-determined by using the :
i following expression:
IR (Mega-ohms) 1 (f(1 Meoa-ohm Der KV) + 1-1
- 1000 (ft) 1 n
Length (ft)
Additionally, in determining the insulation resistance levels required for nuclear instrumentation cables, an assessment of the minimum insulation resistance value (e.g.. one mega-ohm) and-its potential impact on-the functionality of these cables shall be evaluated.
In addition, an ac or de high potential (Hi-Pot) test for power cables.
greater than 1000 volts (V) shall be performed after the post-fire Megger tests to assess the dielectric strength. This test provides-assurance that the cable will withstand the applied voltag'e dur.ing and after a fire. The high potential test shall be performed for a 5 minute duration at 60 percent of either 80 V/ mil ac or 240 V/ mil dc (e.g.,
125 mil conductor insulation thickness.x 240 V dc x 0.6 18,000 V dc).
The table below summarizes the Megger and Hi-Pot test voltages which, when applied. to power, control and instrumentation cables, would constitute an acceptable cable functionality test.
OPERATING MEGGER TEST HIGH POTENTIAL Ty_PE VOLTAGE VOLTAGE TEST VOLTAGE' P
i Power 2 1000 V ac 2500 V dc 60% x 80.V/ mil (ac)-
60% x 240 V/ mil (dc)
Power
< 1000 V ac 1500 V dc*
None Instrument 1 250 V dc 500 V dc None t
and s 120 V ac Control A Megger test voltage cf 1000 V de is acceptable provided a Hi-Pot test is performed after the Megger test for power cables rated at less than 1000 V ac.
The electrical cable functionality tests recommended above are one'.
acceptable method. Alternate methods to assess degradation of cable functionality cre permis:ibic. Other prepc:cd testing citernctive'0111 r
a O
- be evaluated by the staff iff6E?iEEsptib~fift The above table summarizini t6E~Megg5 Find"yfon' a case-by-case basis ~.
Hi-Pot test voltages are
" typical" and the applicant can follow the applicable-industry standards and manufacturer's recommendations for the / specific' cable application in' the performance of the insulation resistance and Hi-Pot tests.
VJ TATR70VEFTESTING(NUMARC,TVAand-UL)
ThiTiiFIEfeh! Eiit1EiTriilli6didifiThe?UsidTtIIliilHiiiithiffliEEfi6 nil l ti?6f.
Eabl difd@ ho s eidabl elttayibrTrE0ewai3 fife! ba rdi e withbut?cialesMThisitestingLmethodisonsistslof(e$ test {specimensftested xpdsthgpidiulatsd - ~
wiresWanC cablesntfritedWo'tagestMulevatedstemperhtdres11hsa ~ ~ ~
' i rbulit!1 sg ? ai rfilled i TheitsinperstU Felpro fil s7for?fsg uist i ngs t65 '
c tesperaturefin by s theMWG r8;ba$thsMi'rf ovenidu ri rigi thiilts s t31 Rtheitempei atu fei mdis0 rez copperconductortduH n' ithe?fireMxposuret ofithose~~"
g CablQta[jy tacepayiteltyjcimej[whi chheit{s tedji thoj2tj$apl e%
TheTitiff Tfliidiithi~'tiiffisillid3?dsiEFitiid?FETOEshbjiEEU 72Q06tl rna o flinVesticj ati ont f6di feiTe'stss fo r5 El ecthi cils C i rcui tIProtect IVe~~~^'
Sys tems sis su eM:umbes 2F Augu s ts1991MAppendin B M Q u alli fj ca ti o@Tsif for CifcuitTIiitegtityiLordssulated$ElectrisaEWireMaddiCableD'
~ " ' ~ ~
m6dincatidn@4dc@tablef ^y~ ~~jj~ Rt'hdifolloWing?~in E16stricsifCircuitiProtect'ioniS stims" sitl ~ ~ ~ ~ ~
E !DdFf6dithsfil f?61lF6?fEst%fEsTdiblisiifs7f6TbifiWiF51isdTa fystsd
^
~'vh1tagsMTh6?cablesXarsEt63beimasit6 red farX666dUcto'rff6FEohddct6F faultslith mult1 aggol uctorsg[cond6ctofic'abljsfandidonductigstoistpuhdifEultssg d
2MTheiEibleiWiinyTEililusfidsibil14s'silb^jiEfiff5?NiisiEi6d{hig^h
- ^ ^ ^
potsntialitestingW[ ecoinmindedf ab6VE2inissctibnflV$~ Cable ~^
lhs@tfon}Telsgg ~ ' ~ " ' " " ' ~ " ~ ~ ~ " ~ ~~~ 373hi?iiiiiiEtif6FEEIiWiEshidhisilidlifsiilSi?f6FEs}Iif?isiipiEf?iiiip6isd 'ontthe?:Facewayjbysthelso11distreamLthstNas?dsscribediislUL%17.24k' Appendix M p3ragtaphi83J1 Q J s y t @ M Rsd g be jb[ formed [ " VI. CABLE THERMAL EXPOSURE THRESHOLD The following is an acceptable analysis method for evaluating cable functionality. This analysis is based on determining whether a specific insulation material will maintain the electrical integrity and operability within-a-raceway fire barrier system during and after an external fire exposure. In order to determine cable functionality, it is necessary.to consider-the operating cable temperatures within the fire barrier system at;the-onset of the fire exposure and the thermal exposure threshold (TET). temperature of the cable. For example, if the TET of a specific. thermoplastic cable insulation (Brand X) is 149 *C [300 *F] and the normal operating temperature within the fire barrier system is 66 'C [150 'f], then the maximum temperature rise within the fire barrier
ci
- 1
' + J' system shall not exceed 83 *C [150 *F] during_ exposure to an external fire of.a duration equal to the required' fire resistance rating of the barrier. For this example the TET limitf for Brand X cable is 83 *C [150 '*F] above the cable operating temperatures within the' fire barrier - system at the onset of the external fire exposure.1The cable TET: limits in conjunction with a post test visual cable inspection and the Hi-Pot test described above should readily demonstrate the functionality of the cable circuit during and after a fire. The cable normal operating temperature can be determined by loading cable specimens installed within a thermal barrier system in the test' configuration with rated voltage and current. The TET temperature' limits for most cable insulation may be obtained from the manufacturer's published' data which is given as the short-circuit-rating 111mit. 'With the known TET-and normal _ operating temperature for each thermal _ barrier-system configuration, the maximum temperature _ rise' limit within a fire barrier system may then be determined. ,p
n e 4-Enclosure'1 FINAL DRAFT TO: ALL HOLDERS OF OPERATING LICENSES OR CONSTRUCTION PERMITS FOR NUCLEAR POWER REACTORS
SUBJECT:
FIRE ENDURANCE TEST ACCEPTANCE CRITERIA FOR FIRE BARRIER' SYSTEMS USED TO SEPARATE REDUNDANT SAFE SHUTDOWN TRAINS WITHIN-THE SAME FIRE AREA (SUPPLEMENT 1 TO GENERIC LETTER 86-10, " IMPLEMENTATION OF FIRE PROTECTION REQUIREMENTS") PURPOSE The U.S. Nuclear Regulatory Commission (NRC) is issuing SuppTshiihGilto Generic letter (GL) 86-10, " Implementation of Fire Protection Requirements," April 24, 1986, to di:seminate the review guidance contained in Enclosure A-1, " Fire Endurance Test Acceptance Criteria for Fire Barriers Used to Separate Redundant Safe Shutdown Trains Located Within the Same Fire Area." This guidance will be used by the staff to review and evaluate the adequacy of: fire endurance tests and fire barrier systems thet cy be proposed by licensees.or applicants in the future to satisfy ixistinglNRC fire protection rules and 4 regulations. This guidance refines add ^clirifies the fire barrier testing acceptance criteria specified by GL 86-10, for application in that specific. (future review) context. BACKGROUND On April 24, 1986, the NRC issued GL 86-10 in order to give the industry additional guidance on implementing NRC fire protection requiiements. The guidance in GL 86-10 did not change the requirement to separate one-safe shutdown train from its redundant train with either a 1-hour or a 3-hour fire rated barrier. In Enclosure 2 to GL 86-10, the NRC staff responded to industry questions. Question 3.2.1 of the enclosure provided the staff position on fire endurance test acceptance criteria for fire barrier cable-tray wraps. In its response, the staff referenced -statidTthit7 Chapter 7, " Tests of Nonbearing Walls and Partitions," of Natiohal'FiPe"PFotection Associa< n (NFPA) Standard 251, " Standard Methods of Fire Tests of Building ConstrL ,on," as being kayapplicable to cable-tray fire wraps. On July 30, 1991, the NRC established a special review team to identify and evaluate technical issues related to the Thermo-Lag 330-1 fire barrier system. On August 6,1991, the NRC issued Information Notice (IN) 91247, " Failure of - Thermo-Lag Fire Barrier _ Material to Pass Fire Endurance Test." This IN gave licensees information on the fire endurance test' performed by Gulf States Utilities Company on a Thermo-Lag 330-1 fire barrier installed on a wide-aluminum cable tray and the associated fire test failure. 0n December 6, 1991, the NRC issued IN 91-79, " Deficiencies in'the Procedures for Installing Thermo-Lag Fire Barrier Material," which gave information on deficiencies in procedures that the Thermo-Lag vendor (Thermal' Science, Ince morated) provided for constructing Thermo-Lag 330-1 fire barriers. In response.to concerns about the indeterminate qualifications of Thermo-Lag 330-1 fire barriers, on June 23, 1992, the NRC issued IN 92-46,.
d Generic Letter 86-10, Supp. 1-November XX, 1993- "Thermo-Lag Fire Barrier Material Special Review Team Findings, Current Fire - Endurance Tests, and Ampacity Calculation Errors." The staff found the following-problems with Thermo-Lag 330-1 fire barriers: incomplete or indeterminate fire test results, questionable ampacity derating test results and a wide range of documented ampacity derating factors,.some ba'rrier installations that were not constructed in accordance with vendor-recommended-installation procedures, incomplete installation procedures, and.as-built fire barrier configurations that may not have been qualified by valid fire endurance tests or evaluated in 'accordance with the guidance that thc' staff ~ 4cuedinjfjGL86-10. After reviewing ins 91-47 and 91-79, Texas Utilities (TV) Electric. institut6d a fire endurance test program to qualify the Thermo-Lag raceway fire barrier - systems for Comanche Peak Steam Electric Station. Under.this program, TU Electric performed an initial fire barrier test series during the weeks of June 15 and 22, and August 19, 1992. Notwithstanding the fire test acceptance criteria guidance specified in GL 86-10,.TU Electric followed the guidance of,. American Nuclear Insurers (ANI) as specified in ANI-Information Bulletin 5(79),-"ANI/MAERP Standard Fire Endurance Test MLthed to Qualify a Protective: Envelope for Class IE Electrical Circuits," July 1979. As result of NRC interaction with TV Electric regarding its fire tests, the NRC concluded that there was uncertainty on the part of licensees as to whether or not the ANI test method established a level of fire. barrier performance equivalent to that established by the GL 86-10 acceptance criteria. In addition, the NRC staff recognized that the 1-hour and 3-horr raceway fire barrier systems are unique and that additional guidance on:tb proper implementation of the GL 86-10 acceptance criteria would be useful. AREAS OF CONCERN The experiences with Thermo-Lag fire barrier systems at TU Electric recounted above raised the following general concerns: (1) The fire endurance test acceptance criteria used by other fire barrier vendors, applicants, and licensees may not meet the acceptance criteria of GL 86-10, and may not fully demonstrate the' fire barrier performance-intended. (2) Certain past cable functionality testing (i.e., circuit. integrity. monitoring) may not fully demonstrate the capability of protected circuits to function during and after a postulated fire. f)RE ENDbRANCE CAPABILITY NRC Oualification Recuirements and Guidance for Fire Barriers Section 50. 48 of 10 CFR requires that each operating nuclear power plant have - a fire protection plan that satisfies General Design Criterion (GDC) 3. GDC 3. requires'that structures, systems, and components important to safety be b
c; o: C is -Generic' Letter 86-10, Supp. 1 November XX, 1993 r designed:and located to minimize, in a manner consistent-withLother. safety. requirements, the probability and effects of fires. Fire protection features-required to satisfy GDC 3 include features to ensure that one train of those systems necessary to achieve _and maintain shutdown conditions.be maintained-free of fire damage..One means of complying with this requirement'is to separate one safe shutdown train from its redundant train with fire-rated barriers. The level of fire resistance required of the-barriers,1-hour or-3-hours, depends on the other fire protection features'in the fire: area.- The NRC issued guidance on acceptable methods of satisfying the regulatoryf requirements of GDC 3 in Branch' Technical Position (BTP) Auxiliary and Power Conversion Systems Branch (APCSB) 9.5-1, " Guidelines 'for Fire Protection for. Nuclear Power Plants;" Appendix A to BTP. APCSB 9.5-1; BTP Chemical Engineering! Branch (CMEB) 9.5-1, " Fire Protection for Nuclear Power Plants;"_and GL 86-10. In the BTPs and in GL 86-10,.the staff stated.that. the fire resistance ratings of fire barriers'should be established in accordance with NFPA Standard 251, " Standard Methods of Fire ~ Tests of Building Construction and Materials," by subjecting a test specimen that represents the materials, workmanship, method of assembly, dimensions, and configuration for which a fire rating is desired' to a " standard fire exposure.'" Some licensees have used the acceptance criteria of ANI. Bulletin No. 5(79), tof evaluate the performance of their fire' barrier systems. The ANI. test- ' methodology, whiWAnl?isisidif6FinsuFahEs5HF)TWFlIFtest specimen be commentor) iequi?dEtfiaTEiblislithin"the~ fire ~ oinIMhly)(ANIisthe 4 monitored for circuit integrity while the test specimen is subjected to'a test fire that follows the. standard time-temperature curve specified in American Society of Testing and Materials (ASTM) Standard E119, " Standard Methods of: Fire Tests of Building Construction ~ and Materials," and to a hose stream' test. Under this criterion, the fire barrier system is evaluated by monitoring the M-capability of the cables inside the fire barrier to pass a low voltage circuit integrity test. During the _ fire and hose stream tests, 'if. cable circuit. integrity is maintained, the tests are considered. successful. LThe ANI' test methodology does not specify the following GL 86-10 acceptance criteria: ~ (1) The fire barrier design has withstood the fire endurance' test without1 the passage of flame or the ignition of cotton waste on the. unexposed side fo, period of time equivalent to the fire-resistance _ rating. required of the barrier. i k -b American Societv for Testing and Materials Standard E119 was adopted by NFPA as NFPA Standard 251. uad
. o Generic Letter 86-10, Supp. 1 - November XX,!1993' F (2) Analysis of temperature levels recorded on the unexposed side of the-fire barrier demonstrates that the maximum temperature rise does not exceed 139 *C [250 *F] above ambient temperature. (3) The fire barrier remains intact and ~does not. allow water t'o be. projected beyond the unexposed surface during the hose stream test., " Interpretations _of Appendix R," to GL 86-10i provided additional guidance with respect to the term " free of fire damage" as used in Appendix R. Interpretation 3, " Fire Damage," stated: "In promulgating Appendix R,~ the Commission has provided methods acceptable for assuring:that necessary. i structures, systems, and components are free from fire damage _(see. Section III.G.2a, b,'and c), that is, the structure,-system or component under consideration is capable of performing its intended function during and after the postulated fire, as needed." ofthetestacceptancecriteriastatedinGL'{86-10(1) clarifies the applicability j The review guidance provided in Enclosure A-raceway fire barrier systems, (2) specifies a set of fire endurance ten acceptance criteria.which are acceptable for demonstrating + hat fire barrier systems can serveLthe-required fire-resistive function and maintain the protected safe shutdown - train free of fire damage, (3) specifies acceptable options. for~ hose. stream testing, and (4) specifies acceptable criteria'.for functionality-testing of ' cables when a deviation is necessary, such as when the fire barrier temperature rise criteria are exceeded and the fEigsiisyjm@ cables sustain visible damage. The test methods and acceptance criteria specified 16fthiTidslisiF5?are acceptable for determining the adequacy of fire barFisF?systFEiliF6)osed by licensees or applicants in the future to satisfy NRC ^^ protection? rules and-regulations. Ap;licants or licensees may propose alterm.!ve test methods _ and acceptance criteria to demonstrate an equivalent level of piotection;-the staff will review such proposals on a case-by-case basis. EnclosureB-231sa comparison of this review guidance against the GL 86-10 acceptance' criteria. Fire Endurance and Functionality Tests - Evaluation 'and Acolication of-Test Results The fire endurance qualification test is successful f6iii?FEEEEyjfifs45"FFisij : if the fellowing conditions are satisfied (see EncloidreT3", ~"FirTBiFFi3F" ^ Testing Acceptance Criteria / Logic' Diagram"): 2 The 163 *C [325 'F] temperature condition s cified in GL 86-10 was established by allowing the 4eter=1 temperature of tIii[tinsip6sidfiBEYdffthi ffFesbiFfieMto rise 139 *C [250 *F] above ambient ~litf6rstHFy~i'iFtTmbiFiYUiii, j Yhich~ sis ^aisumed to be 24 *C [75 *F] during the fire test. 4
m r Generic Letter 86-10, Supp. -5. November XX,;1993 (1) The siRMs internal temperature of the fire barrier system, as mea'sured on the exterior surface of the raceway or component, did not rise more than 139.*C [250 *F] 'above its. initial temperature; and WidEsblsi?d6?EBiji6nistiiifsTIEdliididsin["on~i,ltiit?sp~idimen,~ fhe (2) fhip6Eti35~~6f th5'pf6tEEtid'Eibles~oFE5sp nis"fivealed 'no signs of degraded conditions from the thermal effects of the fire exposure; and (3) The fire barrier system remained intact during the fire exposure andz hose stream tests without developing any openings through.which the protected component, raceway, or cables are visible. For raceway fire barrier systems, the staff adopted the hose stream testing' methodology specified in NUREG-0800, " Standard. Review Plan (SRP) fo'r the Review of Safety Analysis Reports for Nuclear Power Plants," Section 9.5.1, " Guidelines for Fire Protection for Nuclear Power Plants," Revision.2,- July 1981, Position 5.a. This SRP position established the acceptability of. using the fog nozzle method for hose stream testing of. fire barrier penetration seals. The fog nozzle hose stream test method is an acceptable option for tests of the entire raceway fire barrier system under the new staff position. The review guidance provided in Enclosure A-I? clarifies'that, if cables show ' igns of thermal d s.heistindifd!tiiD_egradation dw4ng the fire"Yest-sI7s[ result"?ofiexpgWMid t fire, the licensee can submit to the staff for review a devisti3R~bisEd~~oEI' demonstration of the functionality of the thermally-degraded cables and provides specific guidance for demonstrating cable functionality, including subjecting the cables to Megger'and high-potential tests. The results of these tests can be used to determine.the. insulation-resistance characteristics of the thermally damaged cable and to determine if-the thifinallyWgead6d? cable insulation would have been sufficient to_ maintain circuit"f6KEtianalitfduring and after the fire exposure. y 3 Examples of thermal degradation of cable ' jacket and' insulation-materials are: swollen, split, cracked, blistered, melted,-or discolored. I jacket; exposed shield; exposed, degraded, or discolored conductor insulation;- and exposed copper conductor. ' When the temperature criterion _is exceeded 6FE6mji6KeHFdisidF6EEGFI O component operability at the temperature conditioni~e$erienE6d bTth'i' ~~, d component during the fire test must be assessed. Th:t i;, thtfire [iFI endurance test results that are judged acceptable on the basis o.f a "v^lidal ~ j inspection of certain components may not be applied to other components without_a specific evaluation.
f-I Generic Letter 86-10, Supp. I~ November XX,-1993-- IMPLEMENTATION .This section de. scribes how the NRC plans to use the review guidance contained. in Enclosure A-1. After this supplement to GL 86-10 is issued, except :in those cases in Which an applicant or licensee has proposed an acceptable alternative fira endurance test method and acceptance criteria that-demonstrates an equivalent level of fire protection, the NRC-will'use the methods and the criteria specified in the enclosed review guidance. to'(1). evaluate fire endurance testing programs proposed. by--licensees or ' applicants in the future for demonstrating compliance with pertinent NRC fire protection rule., and regulations and (2) review the adequacy of the fire barrier' systems proposed in the future by applicants or licensees. ACTIONS RE0 VESTED None. REPORTING REOUIREMENTS None. BACKFIT DISCUSSION The guidance transmitted by this generic letter supplement will be used'byf the staff for rev.ew and evaluation of +he adequacy of fire barrier systems and fire endurance tests tht may be proposed in the future to satisfy NRC-fire protection rules and regulations. This guidance refines and clarifies the guidance specified in Generic Letter 86-10 for. application in that future review context; specifically it (1) clarifies the applicability of-the test acceptance cMteria stated in GL 86-10 to raceway fire barrier systems,-(2) specifies a set of fire endurance test acceptance criteria which are-acceptable for demonstrating that fire barrier systems can serve the required fire-resistive function and maintain the protected safe shutdown train free ofJ fire damage, (3) contains acceptable options for hose' stream testing, and (4) specifies acceptable criteria for functionality testing of cables when-a-deviation would be necessary, such as if the fire barrier temperature rise criteria are exceeded and the cable sustains visible damage. No generic or plant-specific backfitting is intended orf appr'oved-at,this time. in connection with issuance of this review guidance. The staff may; consider the need for further generic action in.that regard,. if the industry guidance - currently under development for addressing the pertinent fire protection : issues, is substantively inconsistent with this staff review guidance; but._ such action would'be separately justified in accordance with the criteria of 10 CFR 50.109 and existing NRC backfit procedures. ' Similarly, if plant-specific backfits are proposed by the NRC staff consistent with this review guidance, the proposed backfits would be justified on a case basis in' accordance with the criteria of 10 CFR 50.109 and existing.NRC backfit. procedures.
t: Jcv ~ Generic. Letter 86-10, Supp. 1-November XX,11993 If you have any questions about this matter, please centact~ one of the contacts listed below or the appropriate Office of Nuclear Reactor-Regulation project manager. Sincerely,- f. i James G. Partlow Associate Director for Projects Office of Nuclear Reactor, Regulation
Enclosures:
A1. NRC Staff Position on Fire Endurance ~ Test Acceptance Criteria for Fire Barrier Systems Used To Separate Redundant Safe Shutdown Trains Within 3 the Same Fire Area. 82. Comparison of Staff Position on Fire Endurance -Test Acceptance Criteria. for Fire Barrier Systems Used To Separate Redundant Safe Shutdown Trains Within the Same Fire Area to the Acceptance Criteria of GL 86-10. G3. NRC Fire Testing Acceptance Criteria Logic Diagram. ? D4. List of Recently Issued Generic Letters Technical Conta_t: Patrick H. Hadden,'NRR I (301) 504-2854 Lead Project Manager: William H. Dean, NRR (301) 504-1321 [ Filename: G:\\GL8610PC\\GL8610SI.PC2] k 2 + 'i ll
y v. r Enclosure,2 FINAL DRAFT STAFF RESPONSES TO PUBLIC COMMENTS ' SUPPLEMENT 1 TO GENERIC LETTER 86-10-- _ FIRE ENDURANCE TEST ACCEPTANCE CRITERIA FOR FIRE BARRIER SYSTEMS-USED TO SEPARATE SAFE SHUTDCWN FUNCTIONS WITHIN.THE SAME FIRE AREA BACKGROUND f On November 18, 1992, the U.S. Nuclear Regulatory Commission (NRC) staff met with the Nuclear Management and Resources Council (NUMARC) to discuss fire barrier testing acceptance criteria for fire barrier systems used.to. separate.-
- safe shutdown functions within the same fire area. At this public meeting, the NRC staff provided its proposed position to NUMARC. -In a letter of December 8,1992, NUMARC provided its comments on the proposed staff position.
In addition to the comments received from NUMARC, the NRC staff received-comments from the Tennessee Valley Authority and fire barrier manufacturers, p Changes were not made to the proposed criteria based on these comments prior to publication of the proposed criteria in the Federal Reaister. :However, the~ comments were considered as part of the public comments in this document. On July 23, 1993, the NRC published proposed Supplement 1 to Generic Letter (GL).86-10 in the Federal Reaister and invited comments. The comment. period' expired August 23, 1993. Comments were received anonymously and from Tennessee Valley Authority (TVA); Underwriters Laboratories, Incorporated (UL); Winston and Strawn; William A. Thue; Ohio Citizens for Responsible Energy, Incorporated (0CRE); American Nuclear Insurers (ANI); Consumers Power; Entergy Operations, Incorporated; Philadelphia Electric Company; NUMARC; Florida Power and Light Company; Arizona Public Service Company; Iowa Electric Light and Power Company; Southern Nuclear Operating Company; Georgia Power Company; Darchem Engineering Limited; and an alleger. COMMENTS AND NRC STAFF RESPONSES 1. Anonymous Letter of November 30, 1992, to Chairman Selin (Attachment 1)' ((MMENT 1 - Hose Stream Test Methods "The acceptance of the fog nozzle appeared to be based around' two facts; the fact that the standards allow you to burn for one _heur and hose: stream and if you fail you can the run for 30 minutes and hose stream? again therefore the full hour can be the fog nozzle, the other isLthat the utilities will fight their fires with fog nozzles." STAFF RESPONSE t Generic Letter 86-10 " Implementation of Fire Protection Requirements,"- established that Chapter 7 of National Fire Protection Association (NFPA) Standard 251, " Standard Methods of Fire Tests of Building Construction - and Materials," provided 'the basis for-the staff position for 3 qualification testing of raceway fire barriers. This position is-not J changed by Supplement I to GL 86-10.
a f ' NFPA 251, Chapter 7, " Fire' Test Acceptance Criteria for Nonbearing e Partition Walls," allows the hose stream tests for a nonbearing1 wall to; be. performed on a duplicate test specimen after. the specimen-has been exposed _ to -the standard test fire for a period equal-to one-half'of the fire resistance rating desired, but for not more than one hour (e.g., after a 30 minute fire exposure to-qualify a 1-hour fire barrier andL after a'one~ hour. fire exposure to qualify a 3-hour. fire barrier). After the fire exposure, the-test specimen is subjected to'a solid' hose stream-4 test. The NRC staff position accepts'this hose stream test method. ^ The staff also finds the application of.the hose-stream test -after the - completion of the full fire endurance test period acceptable. If this: method is used, one of the following hose stream test options ~can be-applied: A solid hose. stream applied at random to all exposed surfaces of the> test specimen through a 2%-inch (6.4 cm) national standard playpipe w'th a 1%-inch (2.9 cm) orifice at a pressure of 30 psi;(207 Kpa) fat a distance of 20 feet (6.1 meters) from the specimen. The duration. of the hose stream application is 1 minute for a 1-hour. barrier and 2% minutes for'a 3-hour barrier; or y A fog hose stream applied at random to all exposed surfaces of the test specimen through a 1%-inch (8.3 cm). fog nozzle -set at. a l discharge angle of 30 degrees with a nozzle pressure of 75 psi 3 (517.5 Kpa) and a minimum discharge of 75 gpm (284Lipm) with the tip ~ of the nozzle at a maximum of 5 feet (1.5 meters) from the test. specimen. The duration of the hose stream application is 5 minutes for both 1-hour and 3-hour barriers); or o A fog hose stream applied at random to all exposed surfaces of the test specimen through a 1%-inch (8.3 cm) fog nozzle set.at 'a-discharge angle of 15 degrees with a nozzle pressure of 75 psi (517.5 Kpa) and a minimum discharge of 75 gpm (284 ipm) with the tip' of the nozzle at a maximum of 10 feet (3 meters) from' the test specimen. The duration of the hose stream application is 5 minutes : i for both 1-hour and 3-hour barriers. NRC staff guidance in NUREG-0800, ~ Standard Review Plan (SRP), Section 9.5.1, " Fire Protection For Nuclear Power Plants," specify these hose stream methods for fire barrier penetration seal fire endurance tests. Therefore, the application to these hose stream test options'to fire
- r barriers systems used to separate safe shutdown functions within the same-fire area is consistent with existing staff guidance. Furthermore, it is.
the staff view that a fog hose stream test (after a full-duration fire =i test) satisfies _the.same fire safety objectives for fire barrier penetration tests as raceway fire barrier systems. Staf f acceptance of a fog hose stream test (after the full duration fire test) is also based on the following considerations. (1) Nuclear power plant fire protection programs are based on the defense-in-depth concept. This concept relies on the prevention of fires through administrative- [ i t
w ~ x Ll 1. ~ O in. p <c 3' h 4 ~ -3. ^ control of transient combustibles 'andlignitionisources.)This?isl coupled - l j with installed plant fire protection features which provide l fire. separation-between safe' shutdown. trains'and the: ability to rapidly:. 'M x detect, control,:and suppress fires that occur;despite the prevention l ,i effort.s; -(2):Due to the fire resistive constructioniof nuclear.powerc facilities,?the fire. protection program defense-in-depth, and. the! fact. a that combustible fire' loads in; nuclear pow'er; plants 1are-generally _. low,; 4 significant fire related structural challengesf(e.g.,1 collapse of cablei u trays) -to the integrity.of ~ the raceway; fire. barriers - are.not _ expected a before the fire is controlled and suppressad by either automaticLfirel 1 suppression systems or the in-plant; fire brigade. L(3) In-area withL fi energized electrical? equipment.(most-~ areas with raceway fireLbarriers), 1 in-plant fire brigades apply' water through fog; streams.for'controllinge 1 4 such fires..(4).The pressures and the discharge rates from fog stream H 4 hose streams provide sufficient cooling and eroding,affects' to'evaluatei the fragility of the--barrier system;after the full-duration fire exposure. 1n The staff did not chage[its proposed staff position or acceptancei I criteria'in response to this' comment. COMMENT 2 - Hose Stream Test Criteria. "The standard was written for another purpose entirely when..it. addressed the hose. stream, we:now require no water to pass-thel barrier."' STAFF RESPONSE lq It is not clear what is meant by the comment. Supplement 1-to GL 86-10 1 is consistent with the acceptance criteria of NFPA 251, Chapter 7, in that it specifies that the, fire barrier should remain intactrand prevent-the projection =of water beyond the unexposed surface 'of-the fire barrier - 3 during the hose stream test. The staff did'not change its proposed staff jl position or acceptance criteria in response to'thisicomment. q COMMENT 3 - ASTM Hose Stream Tests "The new ASTM standard for_ envelopes still allows the second: burn but requires both. hose streams be solid." STAFF RESPONSE The bases for'the NRC staff position on~ hose stream testingLis provided 1 Lin the staff response to Comment'I.1, page 12-The. current draft of:thef 4 ASTM standard does not require a hose stream test for raceway fire 4 barriers. The staff did'not change its proposed: staff,posiiion or-g acceptance criteria.in response to this comment. M j .N ~ COMMENT 4 - ULLHose-Stream Tests 4 "U.L.'s new envelope standard uses solid hose streams." 1 mi
- u. ; -
2 :- .u.
=- = - -
- 1
, y (~ ' y Di A a-p >, --a : + y r ' 4- -STAFF RESPONSE-The bases-for'the-NRC staff > position or. hose. stream testing.are'provided. in the: staff response.to Comment-I.lc page 1.J The' staff did not. chang'e.- its proposed staff position or acceptance criterialin response to this: l comment. COMMENT 5 - Penetration Seal Hose-Stream'TestsL g "Thepenetrationsealindustry:specifica11M.has'theauthorityunder: NUREG . i" 1 0800 to use the fog nozzle:however has_always used the solid streami because the fog nozzle produced weak systems;in the market place." j n STAFF RESPONSE The Standard Review Plan accepts'the use:of fog hose Lstream t'estsIfor: penetration seals. The intent of the comment is not clear. ' Supplement.1J to GL 86-10Jprovides' guidance that refines a~nd clarifies the fire-barrier s testing acceptance criteria pr'eviously_ specified'in GL 86 for fire.- barriers used to separate redundant: safe shutdown trains within the:same; ,j fire area, but does not ' apply to penetration. seal = fire tests... Therefore,1 the comment is not_ germane to the supplement. The staff di.d not change; 1 its proposed staff-position or acceptance. criteria' in response to this? t comment. COMMENT 6'- ANI Hose Stream Tests 1 ?! "The staff recognized that the NRC had no standard for env'el_ ope systems ~ l and recognized the ANI #5 standard along with NFPA 251,1both solid stream.- but more than that the ANI which has been used unti1~now wouldn't allow: 0 the second burn and wouldn't certainly all'ow the fog nozzle." STAFF RESPONSE i The bases for the NRC staff position on hose stream testing are provided in the staff response to Comment.1.1, page 1. ThestaffendorsesNFPA251,sbutdoesnotrecognized.ANIBulletin5(79h "ANI/MAERP Standard Fire Endurance Test Method to; Qualify a. Protective y Envelope for. Class =1E Electrical Circuits," as an acceptable method.for: 4 testing raceway fire' barrier systems in its review guidance, such~as the? ? SRP. The staff reviewed ANI Bulletin 5(79), and.found,that'it-does j accept the fog nozzle hose stream test. The staff did not change its-S proposed' staff. position or acceptance' criteria ~in response to this y comment. 7 COMMENT 7 - Foo Nozzle Hose Stream Tests d "Until now there hasn't been any-systems either in seals or' envelopes ~ accepted with the fog nozzle as the industry standard."- ~ l e d y b w, i y 3< v A=~ .mww ~m, -. o+,. oa-n
v hOj ~ STAFF RESPONSE The bases for. the NRC: staff position,on hose-stream testing are provided - in the staff response to Comment I.1, page 1. _The staff.did not change'- its proposed staff position or acceptance criteria ~in response to this e comment. i COMMENT 8 - Use-of Foo Nozzles for Fire Fiahtina "Any fire. fighting school teaches you to fog nozzle. to cool. and.get - closer to the fire for personnel protection but if you want to quench the _. burning' embers and actually put out the fire turn the nozzle to solid, stream." STAFF RESPONSE
- i The staff agrees that fire fighting ;chools instruct trainees to;use fog.
streams on fires involving enercized elet.trical cables or equipment until the electrical hazard _can be electrically isolated. Assuming that the redundant safe shutdown train is protected by a raceway fire barrier. system and the other train is on fire, the fire would be' cooled and controlled by either an automatic fire suppression system or by the plant fire brigade. After the affected train has been electrically isolated and flaming combustion has been eliminated, the fire brigade can complete the ' final phase of. fire extinguishment. This phase will require quenching burning embers by saturating deep seated smoldering fires, such as a cable fire, with water. By this phase of extinguishment, the room. temperatures will be sufficiently cooled to the point that they will_not-affect the protected ~ train of safe shutdown functions. The fire brigade under these conditions may use a narrow fog pattern or a straight' stream to complete the final extinguishment. The staff did not change its proposed staff position or acceptance criteria in response to this comment. II. Tennessee Valley Authority Letter of December 3,1992, to Conrad E. McCracken, Chief, Plant Systems Branch, NRR (Attachment 2) COMMENT 1 - Use of Other Test Standards t "Since minor differences exist between the standard laboratory methods 1 and the specific criteria in the draft NRC document, it is_likely that! confusion will occur at-a later date regarding the acceptability _ of these different methods unless the issue is clearly addressed now." "TVA recommends that the-draft NRC document be revised to recognize UL l Subject 1724, and other relevant laboratory standards, as an. applicable p method _ for performing the fire exposure tests. Tests conducted in- .accordance with laboratory standards should be required to meet all the- = acceptance criteria incorporated in those standards, as if the laboratory performed the tests. To avoid the need to produce an exhaustive list'of relevant standards, TVA recommends that the NRC document be revised to_ f
cJ ..t state, " Fire exposure tests may also be performed in accordance with standard test methods of Nationally Recognized. Testing Laboratories (such-as UL Subject 1724)." 3 -e STAFF RESPONSE The staff reviewed UL Subject 1724 and found that the standard does'not, specify acceptance criteria for internal temperature rise on the external surface of the raceway or within the. fire barrier. system during fire endurance test. In addition, the standard does not provide guidance for-7 thermocouple averaging, assessing the impact of elevated internal temperatures cable functionality, thermocouple placement _ on junction boxes. Based on the differences between the staff position and UL Subject 1724, the staff decided not to endorse UL~ Subject 1724 (or any other test standards) in Supplement 1 to GL 86-10. ~ i Supplement I to GL 86-10 states that licensees-"may propose alternative- ~ test methods and acceptance criteria to demonstrate an equivalent level of protection; the staff will review such prcnosals on a case-by-case basis." Therefore, it is the staff opinion inat licensees can use.or y adapt. laboratory test standards for test programs criteria provided the standards meet the performance objectives established by the acceptance criteria in the Supplement I to GL 86-10. 1
- s The staff did not change its proposed staff position or acceptance criteria in response to this comment.
COMMENT 2 - Tests by Nationally Recoonized Laboratories "The draft criteria have been developed-as part of addressing the acceptability of Thermo-Lag fire barrier systems, which were not rated by' a nationally recognized fire testing laboratory.- Other barrier systems axist which were so rated. For example, Minnesota Mining &. Manufacturing - Co. (3M) electrical protective systems of various types have been rated / listed by Underwriters Laboratories, Inc. These ratings qualify these systems as' rated' fire barriers as required 10 CFR 50 Appendix R'in exactly the same manner as similar ratings for fire doors, fire dampers, etc. Again TVA considers it important that the draft criteria explicitly state that such approved ratings are not invalidated. TVA recommends that the document include a statement such as " Raceway fire barrier systems which have been rated by a Nationally Recognized Testing-Laboratory (e.g., Underwriters Laboratory or Factory Mutual) are acceptable for use without further testing or analysis." STAFF RESPONSE-The staff disagrees with the recommendation. During_its.recent review of; raceway fire barriers,1the staff found that fire barrier. systems' listed by recognized testing laboratories may not meet existing NRC guidance without further testing or analysis. (These findings have been provided to industry through information notices.) To demonstrate that a barrier system is acceptable, the licensee should determine that-the in-plant i .m.
g . cables have-an equivalent level of thermal-digradation resistance to-those cables used to qualify the fire barrier system.- In order to demonstrate this, a licensee may have to perform air. oven functionality tests. In addition, the. licensee is responsible -for assuring that. the-listing bounds the in-plant configurations. For. example, a listing which. supports the design and installation of a fire ~ barrier system on a 24. inch wide cable tray may not bound the application of this fire Larrier: material on either a 36 inch wide tray or a 12 inch wide tray..The; demonstration of structural and the thermal performance.of fire. barrier systems on various cable tray widths and conduit diameters by fire endurance testing is necessary to bound the various in-plant-configurations. The staff did not change its proposed staff-position or acceptance criteria in response to this comment. COMMENT 3 - Previous Accendix R Exemptions "NRC has explicitly reviewed and approved specific Appendix R deviations-and exemptions for electrical fire barrier systems at many. nuclear. power plants. Imposition of additional, or changed, requirements to circumstances which have been reviewed and approved constitutes"a backfit under 10 CFR 50.109. Such changes should be. addressed on an-individual-basis, in accordance with backfit procedures..The draft criteria should explicit state that they do not invalidate previous NRC-approved deviations or exemptions." STAFF RESPONSE Supplement 1 to GL 86-10 provides fire _ test acceptance criteria for future fire endurance qualification tests. The supplement does not address previous _ exemption requests and is not intended to invalidate p evious NRC-approved deviations ~or exemptions.- If the technical basis for an exemption or deviation relied on the installation of a fire barrier, Supplement 1 to GL 86-10 will not change.the basis:(the installation of a fire barrier) for approving the exemption or deviation. However, it remains the responsibility of-the licensee to demonstrate that the fire barrier specified in the exemption or deviation request, can perform its specified fire resistive function. The staff did not change its proposed staff position or-acceptance criteria in response to this comment. COMMENT 4 - Insulation Resistance Testina "The formula for determining minimum acceptable insulation resistance for cables (which appears on page 3 of the attachment to the draft criteria)- is taken directly from IEEE.690-1984, section A.10.1..The Megger tests for which this formula is to be used to determine acceptance values include tests-to be done during exposure to fire temperatures (fore instrumentation cables) and immediately after such exposure.. This IEEE standard establishes the acceptance criteria for new cables at room
O y - temperature'immediately following installation. Applying this' formula for determining the acceptance values for insulation rer.istance tests to' be conducted at elevated temperatures has the affect of. imposing more restrictive requirements than the cable had to meet when new recognized inverse relationship between insulation resistance, due to the. and. temperature. This would be a backfit which TVA considers technically _ inappropriate. - NRC_ should apply the IEEE 690-1984 criteria: for assessing: minimum insulation resistance at room temperature, as intended." STAFF RESPONSE GL 86-10, Enclosure 1, " Interpretations of Appendix R," stated that:"Ini i promulgating Appendix R, the Commission has provided methods-acceptable-for assuring thO necessary structures, systems and components ~are free from fire damage. That is, the structure, system or component under consideration is capable of performing its intended function during:and after the postulated fire, as needed." The purpose.of the acceptancet tests recommended in IEEE 690-1984 is to verify that cable insulation damage did not occur after installation. The formula for determining. the - minimum acceptable insulation resistance value for cable insulation' (Megger) tests represents a general criterion used by the industry:(see: Section 8.2.2 of IEEE 422-1977, " Guide for the Design and Installation of Cable Systems in Power Generating Stations") to-assess.the ~ condition of medium voltage cables. The utility of the formula:is not tied to'a specific temperature, but to maintaining an insulation resistance-value-- which will support the current carrying function of the cable. In the case of instrumentation or special application. cables where circuit ( performance is-sensitive to changes in insulation resistance the' staff-recommends that insulation resistance measurements be taken during the. fire endurance. testing in order to demonstrate functionality during the fire exposure. COMMENT 5 - Instrumentation Cables "The attachment to the criteria requires an evaluation of the. impact ~ minimum insulation resistance value on the functionality of' instrumentation cables, in addition to the insulation testing. ;This implies the need to perform accuracy calculations. Such calculations areL inherently application-specific, and would have to be. performed for each specific instrument. circuit in a power plant which 1s; protected by a. Thermo-Lag fire barrier enclosure. This would be a major effort:which would not materially add to the information obtained from the Hegger and-hi-pot testing. _The NRC's insulation-resistance acceptance criteria' should be of a go/no go_ nature (e.g., IEEE 690-1984), and accuracy _ calculations should only be required for cables'which do not pass:these criteria. The paragraph immediately following. the formula on -page 3 of' the attachment should be deleted." i ' 1 STAFF RESPONSE j i In the case of instrumentation or special application cables where ~ circuit performance is sensitive to changes in insulation resistance the j ~1 _ i z -! l r
x o
- o 7
-9 staff recommends. that insulation resistance measurements be taken during the fire endurance' testing in order to demonstrate functionality during the fire exposure. Sandia National Laboratory (SNL) research studies-have shown that Megger and hi-pot testing may not always discern whether cables protected by a potentially deficient f_ ire barrier. system-(i.e. fire barrier deviation condition) have been exposed tol temperatures ~which would affect an instrument circuit's performance.. Given that insulation resistance is a strong function of insulation temperature. significant. degradation can occur during the fire exposure.~This temperature related effect coupled with the observation that in some. tests cable have failed - during testing which had showed post-test insulation resistance values.of s greater than lo ohms (
Reference:
NUREG/CR-4638/11of.2 Transient Fire Environment Cable Damageability Test Results: Phase I, September 1986). leads the staff to the finding that one can:not rely solely.on ~ post-test measurements. If a' licensee proposes'to justify a fire barrier deviation, then cable functionality should be evaluated based on the f plant-specific application. The staff did not change its proposed staff position or acceptance criteria in response to this comment. COMMENT 6 - Thermal Exoosure Threshold "The concept of thermal exposure threshold (TET) is being applied-inappropriately in section d of the attachment to the-draft criteria. TET limits are established to address concerns of potential degradation of cable insulation due to elevated temperatures associated with circuit - faults. Exceeding TET limits does not imply an instantaneous failure of cable insulation, but rather establishes a~need to evaluate-long-term acceptability of the cables after it has experienced 'such temperatures. The visual inspections and megger and hipot tests called for by these draft criteria constitute an evaluation to determine whether the insulation has been damaged. TVA recommends that the concept of TET be deleted from these criteria." STAFF RESPONSE The concept of thermal exposure threshold provides the. basis' for mathematical analysis. and correlation of past' and related test data' to be used in the engineering evaluation for1 demonstrating functionality for a specific fire barrier deviation condition., The subject section gives. examples of where the maximum cable temperature or maximum short-circuit temperature with the normal operating-temperature is used to set the appropriate temperature rise limits for the-fire barrier system b. sed.on. the specific cable application. The purpose the subject?section is to provide a conceptual framework for; an engineering evaluation. of fire barrier systems. This methodology is consistent with the previous staff position that an engineering evaluation demonstrate functionality for a 4 fire barrier deviation condition. [ q
y 'o ; _10_. The staff did not change its proposed staff position or acceptance criteria in response to this commer.t. III. Nuclear Management and Resources Council Letter of December 8, 1992, to. Conrad E. McCracken, Chief, Plant Systems Branch-(Attachment-3) COMMENT 1 - Aeolication of Sucolement I to'GL 86-10 "In the case of TSI fire barriers, the NRC has formally declared, through Bulletin 92-01 and its ' supplement, that. existing installations are indeterminate and subject to reverification. The draft acceptance criteria have been developed primarily for the. purposes of application'to. future fire tests to address the TSI situation, and would? ' apply as well to other fire barrier testing that may be performed in the future. The-NRC document discussing the criteria should therefore clearly state that. the test and acceptance criteria are forward looking_ and do not' result;in the need for retesting or analysis of fire barriers previously evaluated and found acceptable by licensees in accordance with NRC Generic Letter 86-10, unless they have been formally identified by the NRC as indeterminate " STAFF RESPONSE Supplement I to GL 86-10 will only be used by the staff to review' future fire barrier testing program 3. This is clearly: stated in the supplement: The staff will continue to use the acceptance criteria guidance specified-in GL 86-10 to evaluate the adequacy of existing fire barrier system designs that have not been declared indeterminate. The staff'did not change its proposed staff position or acceptance criteria in response to-this comment. COMMENT 2 - Enoineerina Evaluations "The NRC draft document discusses the needed for an engineering evaluation to demonstrated functionality in the event that? temperature-limits are exceeded, or visual damage is observed to the barrier or the cable. The draft document states that NRC.riview and approval of this engineering evaluation will be necessary. While we are hopeful that the y NUMARC industry testing program will provide enclosure upgrades that will-j not require the use of these engineering evaluations, there is nonetheless a potential that forthcaing utility efforts to address installed Thermo-Lag configurations-could result. in submittal of large number of such evaluations, and corresponding' delays -in the NRC ~ approval cycle. We therefore, believe the' process for NRC review and approval,. as outlined in the draft document, should provide that existing utility ~ compensatory measures can.be removed following completion of the.. engineering analysis:and any associated modifications to.the barrier.. system. NRC Generic Letter 86-10'provides that utilities' could document these type of analysis for subsequent NRC review during inspections, and j NRC has indicated in the November 13 Commission Briefing that inspections are planned for the 1994-1995 time frame. We believe there would be a-a benefit to developing a generic framework for these analysis, and'
L;p : o providing guidelines that would allow for the removal of compensatory-- measures prior to completion of NRC review. Industry would be willing to. work with NRC through NUMARC to'_ develop such guidelines to the extent they are necessary beyond the explicit evaluation criteria-that will be i provided in the final form of the NRC document'" STAFF RESPONSE A fire barrier systems covered by Supplement 'l to GL 86-10 that does not meet the acceptance criteria of the supplement with respect to barrier burnthrough, temperature rise limits. cable degradation, or barrier. degradation by the hose stream test, does not satisfy.the fire resistive-function specified by Section III.G of Appendix R__to 10 CFR Part 50. Under the supplement, a licensee may request a plant specific deviation - to a license condition or an' exemption.to the regulation based on an engineering evaluation which demonstrates cable functionality. Barrier degradation or cablo damage conditions deviate from Appendix.R fire barrier requirements. Deviations from a plant license'or exemptions to the regulation require NRC approval. GL 86-10 guidance does not supersede a license condition or a. regulation therefore, these-engineering evaluations, which justify a deviation to a licensee condition or an exemption to a regulation, are not' subject to the-provisions allow under the GL. It is expected that.the number of exemption and deviation requests will depend on industry's ability to - conduct a fire endurance testing program which demonstrates that these 1 indeterminate fire barrier systems can provide an adequate level of fire resistive performance and, when properly configured, can perform their specified fire barrier function. The purpose of the_ recommended functionality tests is to justify observed deviation's in fire barrier performance. Engineering analyses justifying these deviations should not rely substantially upon the equipment (e.g., cable) qualification as.the basis for acceptance. Operability determinations are the. responsibility of.the' individual licensees. If a licensee elects to request a deviation to its_ license or an exemption from the regulaticn upon completion of its functionality analysis and any fire barrier modifications needed to support the basis: f of the analysis, the licensee can make the decision to remove its compensatory measures while_ its analysis is being reviewed by the NRC. However, if the staff finds the licensee's request and analysis unacceptable, they may be subject to enforcement actions. 4 The staff did not change its proposed staff position or acceptance criteria in response to this comment. .(OMMENT 3 - Fire Tests of Emoty Enclosures "The criteria, and accompanying flow charts, should more clearly _ address the process for testing with empty enclosures and the use of air. oven cable tests or other cable performance data, on the basis of. measured temperature profiles from the fire tests." y i
9' f STAFF RESPONSE The staff agrees with the comment. The staff position on testing empty. enclosures is provided in the staff response. to Comment. XII.1, -{page 28).. c COMMENT 4 - Thermocouple Placement "Page 8.of the NRC draft document discusses thermocouple placement consideration. The discussion notes that " industry considers (placemer.t_ of thermocouples on cables] the proper location for determining.the temperature rise..." While industry considers that protection of the cables, rather than the enclosure, is the. fundamental safety function,1we agree that placement of thermocouples on thel cables is not the' best ' approach. We would note that the industry positioa paper. on test criteria, provided to NRC on October 26, recommends that thermocouples' be placed on copper conductors, and that testing be performed with empty:.. enclosures. Furthermore, we believe that the copper conductors shoulds provide for measurement of temperatures on surfaces of the enclosure that4 the cable may realistically come in contact with. With respect to cable: trays, we do have a concern that the NRC draft document specifies use of. a copper conductor underneath the cable tray rungs. We believe the appropriate placement for the copper conductor'is on top of the-cable tray rungs, as this will provide for measurement of temperatur'es that would be experienced by installed cables." STAFF RESPONSE i The staff agrees that the cables within the raceway fire barrier system J is the fundamental safety function that is being protected.- To properly-protect these cables, the fire barrier system should maintain the cables free of fire damage, thereby assuring functionality. The staff revised l the acceptance criteria to include guidance on thermocouple placement when cables are not installed the raceway during the fire endurance test. COMMENT 5 - Circuit Inteority Monitorino } "The attachment to the NRC draft document discuss acceptable. methods for determining cable functionality. Section b discusses cable circuit integrity testing, and concludes that this is not.a valid method-for-demonstrating that the protected shutdown circuits are capable ofE performing its required function. We agree with this statement, and believe the criteria-should explicitly state that circuit integrity? monitoring need not be performed. This will simplify the ~ test procedure and provide for more timely performance of post exposure megger testing." STAFF RESPONSE I The staff agrees with the comment and revised the acceptance criteria.to state that circuit integrity monitoring during fire endurance tests;isL not needed to satisfy the acceptance criteria. Circuit integrity testing' at rated voltage is, however, still needed during air oven tests.
m e 0 -8 COMMENT 6 - Cable Functionality "The second paragraph of page 4 of the attachment discusses cable normal operating temperature and its effect on the total. temperature-rise. We agree that cable normal operating temperature is a consideration in the engineering evaluation;' however, we would note the following: Initial operating temperature is only a consideration for power. a. cables, of control and instrument. cables that nay be in the. same enclosure with power cables. Elevated operating temperature need ' not be considered for instrument and control cables in separate enclosures. b. Power cables will not be subject to rated voltage and current prior to the fire exposure,-and may only be intermittently energized, orf not energized at all,- prior to the exposure. The analysis-should-assume realistic conditions rather than rated voltage and current as-4 stated. At the November 19 meeting, NRC stated that the analysis should assume operating voltage and normal current conditions. c. The effect of initialLtemperature on endpoint.is not a simple' ~ function of adding the difference between the initial temperatureL and the ambient air temperature to the measured temperature rise. Appendix V.of NUMARC's draft criteria submittal of October 26 provides a heat transfer calculation relative to the effect of - initial temperature on the endpoint temperature of 90 *C versus 23 *C. This calculation shows the effect-to be minimal (12. *C)-'at one hour, and negligible at three hours. The attachment to the NRC draft document should allow the use of heat transfer. calculations to determine the endpoint temperature rise." STAFF RESPONSE a. The staff agrees that ambient temperature conditions should be-r utilized as the normal operating temperature for instrument and control cables in separate enclosures. b. The staff believes that any engineering evaluation to demonstrate functionality should be conservative to compensate for potential age related degradation over the life of cable systems installed:in the plant. The NUMARC analy' sis did not allow margin for loaded power cables c. subject to self heating effects. NUMARC's basis regarding the effects of the initial cable elevated temperature on-the cable _. thermal response is not. correct. An analysis of: the~ NUMARC heat transfer study by Sandia National Laboratory points to the; failure - to consider that_an energized cable would continue to generate thermal energy by self heating throughout the fire exposure. A o simple sample calculation-of this effect indicates that the-difference between the response of a non-energized cable and an energized cable to a step change in envelope temperature to 250 *C =
- -n [ g ~ ~ G E ~ [' ~. n- -is not.12 *C' as stated in'NUMARC's - submittal ;of October 26, fl99.2, ~ but rather, at least 681*C '(excluding;the, effects ~ of: copper: ,4 resistivity increasing with increased: temperature). The' staff? c-believes that the acceptar.ce criteria!'nust provide' sufficient margin to account for this effect-and other uncertainties'... ~ The staff 'does 'notLagree that heat transfer calculations:alone~ are-sufficient to determine the endpoint, of the.-fire endurance' temperature: rise condition.' It -is not. clear. that. current ~ models are capable' ofi J. demonstrating lthe relationship and effects that;the worst case. cables operating temperature may-have;on the endpoint temperature; rise? 1 Thestaffdid.notchangefitsproposedstaffposition'.oracceptance i criteria in response to=these comments. COMMENT 7 - LOCA Temperature Profiles "The attachment to' the NRC draft document.should state that comparison off fire. test temperature: profiles to existing EQ and LOCA (loss of coolant: accident). test results, or. air ~ oven test results, is an: acceptable! e approach to demonstrate cable functionality."- ' I STAFF RESPONSE The staff agrees with the. comment.provided the analysis incorporates the: temperature rise due to self. heating effects of power cables;- The staff i revised the acceptance criteria (Section III of:the' attachment to the- ~ criteria) as discussed in its response to Comment XII 1,.;(page 28). ' ~ O COMMENT 8 - Thermal Exoosure Threshold "TVA submitted comments on'the NRC draft document by letter to you of; December 3, 1992. Item 6 of.that letter questions the appropriatenessLof' a the cable thermal exposure threshold. (TET) as.a measure of short term cable operability. We concur with this comment." P STAFF RESPONSE l Comment II.6, (page 9) _ ]d See staff addressed cable thermal exposure threshold in its response to. h COMMENT 9 - Insulation Resistance Testino a " Item 4 of the TVA letter referenced above questions the use of:the 'l formula for deteralining minimum acceptablefinsulation resistance on' page) d 3 of the attachment' to the NRC draft document; We' concur with this. 1; u comment.. The_ gim formula;is taken from. IEEE 690-1984, section A.10.1, 1 -and is intended for use.with Lew cables at-room temperature. Testing of a cables. at elevated temperatures (i.e.,-'immediately following the: fire. test) to this. criteria represents a more_ restrictive requirement: th'at the: 1 cable has to meet when new. The formula should only'be used for cables tested at room temperature." i I lj 1 j j r a. 1, a.
g >:d. . 4, STAFF RESPONSE 1 The staff' addressed insulatien resistance testing in its response; to Comment 11.4, (page 7). IV. Nuclear Information and Resource Service Letter of. December 15, 1992, to James Taylor, Executive Director of Operations (Attachment 4) COMMENT 1 - Combustibility "Thermo-Lag is combustible, contrary to 10 CFR 50 Appendix.A and R. The NRC's own testing (and dramatic color photographs) indicate that ' Thermo-Lag is indeed combustible. We understand,.however, thatLthe NRC-is preparing an.Information Notice acknowledging Thermo-Lag's combustibility. Further, we understand the NRC may require utilities:to-consider Thermo-Lag in its analysis of fire loads. It would indeed be ironic to have the fire protection material listed as part of the fire-. protection problem. Moreover, Thermo-Lag is often used in areas required to be free of combustible material. This is itself is evidence of an uncorrectable regulator violation and by itself should require removal of; all Thermo-Lag material from use as fire barrier." STAFF RESPONSE NRC-sponsored tests indicated that Thermo-Lag exhibits combustible 4 characteristics. The NRC provided the results of the tests in Information Notice 92-82, "Results of Thermo-Lag'330-1 Combustibility Testing," December 15, 1992. The stated objective of Supplement I to GL 86-10 is to refine and clarify the fire barrier acceptance criteria specified in GL 86-10. As such, the focus of the supplement acceptance criteria for fire endurance testing,. not combustibility. NRC requirements and guidance do not specify-that fire barrier systems be noncombustible. There ts existing NRC guidance for the use and control of combustibles:in nuclear _ power plants. The NRC fire protection guidance documents provide the following d definitions for noncombustible material: a 1 (a) Material which in the form in which it is used and under the. conditions anticipated, will not ignite, burn, support. combustion, or release flammable vapors when subjected to fire or heat; or-(b) Material having a structural base of noncombustible material, with aL j surfacing not over %-inch thick that has a flame spread rating of not higher than 50 when measured using ASTM E-84, " Surface Burning Characteristics of Building Materials." l The NRC has not changed these definitions. ASTM E 136 is one test method-for obtaining data for assessing a combustibility hazard against these. definitions. l h a 1 1
= r NUMARC, as part of. the industry effort to resolve the technical concerns I with Thermo-Lag fire barriers, is evaluating issues associated with _the combustibility of Thermo-Lag materials. These' issues. include.the use of Thermo-Lag fire barriers to establish combustible free zones'between redundant safe shutdown trains and to construct radiant energy heat shields inside containment. During a meeting of June 29, 1993, NUMARC infomed the staff that it is conducting additional tests to assess the combustibility of Thermo-Lag and is developing a methodology for i reviewing plant-specific Thermo-Lag applications that will be consistent-with the NRC combustibility definitions. -The NRC. staff will review the NUMARC methodology. The staff will provide additional information on^ these issues, which are being addressed independent.of the establishment of fire endurance test acceptance criteria, as appropriate. The' staff did not change its proposed staff position or acceptance criteria in response to this comment.. COMMENT 2 - Hose Stream Test Methods l i "The NRC staff, in its proposed fire barrier criteria,-incorrectly would allow the use of fog nozzle, rather than full-force hose stream test. ASTM E-119, the standard fire test used by the NRC and passed by other-products, requires a full-force hose stream test. We also note that the new, as-yet-unnumbered ASTM test for electrical raceways also would-require a-full hose stream test." STAFF RESPONSE { The bases for the NRC staff position on hose stream testing are provided in the staff response to Comment I.1, page 1. The current draft of the-ASTM standard does not require a hose stream test for raceway fire-barriers. The staff did not change its proposed staff position or i acceptance criteria in response to this comment. ~ j V. Minnesota Mining and Manufacturing Company-(3M Company) Letter of _i December 18, 1992, to Ralph Architzel, Chief, Special Projects Section, Plant Systems Branch (Attachment 5) COMMENT 1 - Operatino Licenses "Do the letters of acceptance and license to operate issued by the NRC [ covering these installations remain valid? If not, why not?"- t STAFF RESPONSE The operating licenses for these facilities are not affected by Supplement I to GL 86-10. Furthermore, nothing in the supplement. invalidates letters from the NRC to applicants and' licensees concerning NRC acceptance of a fire barrier system at a specific facility. The staff did not change its proposed staff position or acceptance criteria in response to this comment. m f
1 s, ci w , COMMENT 2 - Testino Laboratories "3M fire barrier product has over the years been continuously tested to American Nuclear Insurers (ANI) standarde, as adopted by the NRC, and by test facilities, CSTB in France, and Certified Testing Laboratories' (CTL). Unlike the in-house testing practice and procedure of-someL manufacturers,'3M's product testing was conducted in.its facilities under-procedures correlated with UL and Factory Mutual Insurance standards,- resulting in a 3M' product classified and approved by these: organizations. 3 Does the NRC accept tests conducted under.the above. procedures and 4 witnessed, approved and certified by Twin Cities Testing, a nationally recognized testing service, to be valid confirmation of the basis tests and criteria originally established for 3M-product-at UL and SWRI?"' STAFF RESPONSE The staff does not recognized ANI Bulletin-5(79) as. an acceptable method for testing raceway fire barrier systems in itsLreview guidance, such as the SRP. The NRC staff is not familiar with the qualifications or fire endurance testing expertise of Twin Cities Testing Service and,-therefore, cannot respond directly to the question. Typically, the NRC staff" evaluates-fire test programs and fire test results on a case-by-case basis as part of specific' licensing applications. This was the case, for example, for the~recent test programs carried ~out by Texas Utilities (TV) Electric Company for. Comanche Peak-Steam Electric Station (CPSES) and Tennessee Valley Authority (TVA) for Watts Bar Nuclear. COMMENT 3 - Previous Test Results "3M has over the years accumulated a substantial body of data based upon use of a specified 12 inch spacing of thermocouples during fire tests, as 4 directed by ANI. Current testing procedures now indicate a'6 inch spacing requirement. I+. is 3M's intent to conduct all future testing in accordance with this revised procedure. Does-the NRC accept the validity of previously developed data generated at the manufacturers expense in 0 accordance with the established 12 inch standard?" STAFF pESPONSE Supplement I to GL 86-10 will be used by the staff to? review! future. fire barrier tests. This is clearly stated in the supplement. The staff will continue to use the acceptance criteria and guidance specified in- =; GL 86-10 to evaluate existing fire barrier test results and_ system designs. The staff will evaluated the acceptance criteria specified11n the test reports for any such tests'on a case-by-case basis. The staff did not change its proposed staff position or acceptance criteria in response to this comment. j s ?!
n- ,r p q f% COMMENT 4 - Miscellaneous Issues "Previously established. test protocol and performance place emphnis o'n product capability with respect to~ specified areas.of vital concern to public health-and safety, including combustibility, toxicity,: seismic performance, weight, and ampacity derating.. Current efforts to re-evaluate test criteria are focused on product fire performance.. Does the NRC intend to establish as part of the current; test re-evaluation program - an equal emphasis on all aspects of the aoove areas of product ~ performance relating to health and safety issues?.How and when will these areas of concern be tddressed in order to enable manufactures to respond to customer demands for qualified product?" STAFF RESP 0NSE The NRC staff position on combustibility.of fire barriers is provided in its response to Comment IV.1, (page 15). The staff position-on toxicity-is provide in its response to Comment XXIII.3, (page 55). The staff has existing requirements and guidance on ampacity derating and seismic performance. The objective of Supplement I to GL 86-10 is to clarify existing acceptance criteria for conducting and' evaluating fire endurance-tests. Ampacity derating and seismic analyses are cutside the scope of-- the supplement. The staff did not change its proposed staff position or acceptance criteria in response to this comment. [0MMENT 5 - Combustibility "The original NRC-test standard for noncombustibility was ASTM E84. In the current test re-evaluation process the NRC has indicated that ASTM E136 will now be applied. At the NpC public meeting on November 19, 1992, it was stated by NRC rupresentatives-that standard E136 would be interpreted to mean a product equivalent in noncombustibility to fire rated gypsum board. Will the E136 standard as defined in the November 19 meeting be applied against all existing installations regardless cf manufacturer?"' STAFF RESPONSE The NRC staff position on combustibility is provided in its response to. Comment IV.1, (page 15). The staff recognizes ASTM E-84, " Surface Burning Characteristics of Building Materials," as an acceptable standard for determining flame spread ratings. f!owever, flame spre&d alone does not allow a complete assessment of material combustibility. ASTM E-136-is one test method for obtaining data for ascessing the combustibility hazard introduced by materials installed in nuclear power plant in 1 accordance with existing NRC guidance. p
o L: h COMMENT 6 - Hose Stream Tect Methods "The hose stream requirement's of NFPA 251,. ASTM E119, and ASTM E814 have long been recognized ~as providing the mechanical-means of determining e fire barrier product performance with respect to. thermal shock, effects. of erosion and the ability to resist mechanical. abuse.. The new test protocol allows for fog nozzle testing in lieu of the solid stream' test. Wha.t is the basis upon which the substitute fog nozzle. test has-been determined to provide equivalent test-.results regarding _ these ' critical product performance characteristic:.." STAFF RESPONSE The bases for the NRC staff position on hose stream testing are provided in the staff response to Comment I.1, page 1. COMMENT 7 - Application of Test Acceptance Criteria "At the present time there are fire barrier. systems of either one or three hour performance duration at the various utility plant locations. These systems have been provided by one or the other of several manufacturers. Does the NRC intt.J that both systems are. subject to the entire. revised testing protocol and specified performence criteria?" STAFF RESPONSE Supplement I to GL 86-10 currently states that the criteria will be used by the NRC to review the. adequacy of the fire barrier systems being proposed by applicants and to evaluate future ~ fire barrier testing conducted by licensees to demonstrate compliance with existing NRC rules - and regulations. The staff will continue tr use the acceptance criteria. and guidance specified in GL 86-10 to evaluat previous fire barrier test results and system designs. The staff did not *.hange its proposed staff position or acceptance criteria in response to this comment. ' VI. Minnesc ing and Manufacturing Company (3M Company) letter of January .t !3, to Ashok C. Thadani, Director, Division of Systems Safety and Aaalysis (Attachment 6) COMMENT I - Cable Functionality "3M, working with Underwriters Laboratories, has tried various methods for evaluating cable functionality, including oven testing to establish failure points, Meggering before and after fire testing in both air and water, circuit integrity testing under low and high amperage loads during fire testing, and other means. 3M is willing to make this information-available to.the industry to help develop a functionality test method. The question still exists on proper selection of the' cable to be tested ' should it be' artificially aged before testing, as aged cables.will= function differently than new cables. l Cables of the same design, labeled NLPE/PVC, can. fail in an oven evaluation test at' temperatures as 'ow as-325 *F and as high as 750;"F, even though the cables are thought to be
~ g .e a - 2 0-'.- y identical..The choice of. cable will.be crucialf to testing cable functionality.* y STAFF RESPONSE 'The staff agrees that for fire tests that use cables:in-the. test. specimens or for demonstrating cable functionality <for barriers that' deviate from the acceptance criteria (discussed below),ithe proper selection of cables is critical. The staff position specifies that' cables used to demonstrate functionality be representative cf the plant-specific cable configurations to be protected by the fire barrier; system. The Appendix R Rule does not specify functionality: criteria for-electrical equipment or cables. The intent of Appendix R is to protect the shutdown function from fire damage for a prescribed period'of-time'. Appendix R can be met by separating redundant shutdown components with; qualified fire barriers. It is the staff position that_the selection of a qualified barrier can be made independent of the design or nature:of ~ the components to be separated. Therefore it is not necessary to specify b functionality parameters. The fire barrier is qualified if the following conditions are' met during_ the fire endurance test: (1) The internal temperature of theLfire barrier system,- as measured on the exterior surface of the raceway or component, did not exceed 250 *F (139 *C) above its initia1Ltemperature. (2) A visual inspection of.the cables reveals no signs of degraded conditions. (3) The' fire barrier remained intact during'the. fire exposure and water hose stream tests without developing through barrier-openings. Functionality comes into play only in the event that-the; tested fire barrier does not meet (1). or.(2) or' (3) aboie. In this case a licensee may chose to declare the' barrier as deviating from the acceptance criteria and demonstrate' cable functionality. Supplement 1 to; GL 86-10 specifies that licensees submit all deviations and. functionality evaluations to the staff for review and approval. It is also the staff position that Appendix R requirements are satisfied - if new cables are used in the test specimens or for performing functionality tests for barriers that deviate.from the acceptance criteria. VII. Darchem Engineering, Limited Letter of February 2,1993, to Ralph Architzel, Chief, Special Projects Section, Plant Systems Branch-(Attachment 7) COMMENT I f "The fire test proposals at present do not indicate the number, size and types of cable to be used in the fire tests apart from the single cable loading." l l 5
Y. , M4 w [' ~ r < STAFF RESPONSE The staff revised Supplement 1 to GL 86-10 to specify that the preferred - fire test method is to construct the test specimens without cables.. For: test specimens that include cables, cable types -and. loading (fill) should be conservatively representative of plant-specific cables and : loadings. The staff also revised the proposed criteria to specify: that cable: specimens used to demonstrate functionality be representative of;the installed plant-specific cables and configurations that will be enclosed in the fire barrier system. COMMENT 2 - Hose Stream Test Method "The concern is that the new proposals allow for a relaxation in th'e hose stream criterion by including a Water fog as an option. We believe'that. the penetrating power that the impact of a solid hose stream imparts to. the fire protection system around a raceway will not reproduced-by the water fog. This will mean that fire fighting teams will be restricted in its choice of equipment and methodology for tackling the blaze to 4 penetrating through electrical circuit protection systems that'have been qualified against the water fog criteria. It.will also mean fire protection systems may not have the ability to withstand even small amounts of falling debris. We therefore recommend the existing solid-hose stream test be used without alternative. STAFF RESPONSE The bases for the NRC staff position on hose stream testing are'provided-in the staff response to Comment I.1, page 1. COMMENT 3 - Combustibility "The ASTM E136 test method is traditionally used for indicating if a building material will either aid combustion for add appreciable heat to a ambient fire..It is also used for checking insulation materials,.in particular calcium silicate which can have a high paper content. We support the implementation of ASTM E 136 test method as we believe-this test provides essential data in assessing the suitability of materials for use in a fire protection -systems. However the present ASTM E136 standard as it stands excludes coating materials. We would urge that a complete representative section of material including any coating is to be tested." STAFF RESPONSE Coatings are addressed by the Standard Review Plan and other existing NRC fire protection guidance documents which specify flame spread ratings-(measured by ASTM E-84, " Surface Burning Characteristics of Building . Materials") for materials used in nuclear power plants. The staff-did
x 9' b '. _ not' change its proposed staff position or acceptance criteria-in response to this comment. VIII.! Underwriters Laboratories, Inc., Letter of August 19; 1993 (Attachment 8) COMMENT 1 - Hose Stream Test Methods "It is our belief a fire test standard should clearly.l describe. a singul' r: O a reproducible methods to measure a performance criteria for a product or, b system. .t. is also'necessary that consistent results be obtained from-f, the test method.specified..It.is our recommendation,;the-hose stream-b ^ test be limited to the method requiring the playpipe nozzle which, as' 4 stated in the proposed generic letter, 'is specified in Standard NFPA ~ ~ 251." "The elimination of the hose stream methods using a fog fire nozzle currently in proposed Generic Letter 86-10 will result in the Generic-Letter containing a uniform, reproducible test method to measure impact resistance. This test method will provide a. benchmark performance for impact resistance which has been demonstrated to be obtainable.by currently available fire barrier systems."' 1 STAFF RESPONSE ] The bases for the NRC staff position on hose. stream testing are provided in the. staff response to Comment I.1, page 1. COMMENT 2 - Combustibility "It is our belief, the data generated from tests conducted in accordance' with ASTM E136 and ASTM D1929 will not be sufficient'to allow a complete-hazard analysis of material and products used as a fire barrier. 'A test that provides both the temperature of the test specimen at. ignition-as well as the thermal inertia. factor is SSTM E1321 (Standard Test Method for Determining Material Ignition and Flame Spread Properties. Thus, ASTM E136 and ASTM D1929 should be replaced by ASTM E1321 to obtain a more ' complete ignitability profile of the test specimen." "Further, it is our recommendation that ASTM E1354 (Standard Test Method. for Heat and Visible Smoke Release Rates for Material and Products Using. an Oxygc1 Consumption Calorimeter) be added to the list of tests to determine ne heat release and smoke generation rates at specified heating flux (or fluxes)." "The combination of data from ASTM E1321 and ASTM E1354 tests'will' enable'- I the quality of the hazard analysis to be greatly improved as compared to-the analysis possible with the limited data presently being proposed."- p a.
w_ ~,
- X!
x f'$. '['y n ~
- - k.
n=" 79 f* a T(, e ? l.a ~ t g g y l d -232 . STAFF RESPONSE. ASTM E-136 isone' test method for obtaining data;for. assessing?thei. combustibility hazard of materials installed in nuclear power plant in accordance with existing NRC guidance'(see the staff: response'to< S Comment IV.1, (page 15)). The staff, agrees that' additional tests mayf be( L appropriate ~ to fully assess some' materials; and to allow a complete. hazard; analysis of material. However, the stated objective.of Supplement;1 to, GL 86-10 is to refine.and clarify thel fire barrier testing acceptance;. criteria specified by GL 86-10. It is the ' staff's viewithatLthelexisting 4 guidance for combustibility.is adequate. ;Therefore, the staff!did;not. '? change its proposed staff position or acceptance. criteria -iniresponse to. c the comments. f COMMENT 3 - Cable Functionality 9 3m In the area of demonstrating cable functi.onality, Underwriter i Laboratories indicated the differences between' the Cable Thermal Exposure? 1 Threshold Method expressed-in the GL supplement and the cable i functionality testing methods identified in its outline of investigation',s Fire tests for Electrical Circuit Protective' Systems. UL recommended that provisions for air oven functionality testing of cables-be' incorporated into the GL supplement. ~ l STAFF RESPONSE 3 The staff agrees with the comment and revised Supplementil to GL 86-10' toi H include a modified air oven functionality test of cables. The staff also a concluded that UL Subject _1724 has several points of technical" merit asTa testing methodology to simulate and monitor the temperature, profile-within the barrier system. Appendix 8 to UL 1724 states that its requirements cover the adjunct 3 investigation of specific electrical cable insulation: types fcr use-in... c protective systems..." Safety-related electrical cab 1'e systems;in nuclear power plants are qualified ' nder' existing NRC: regulations and u industry standards for their unique environment. Although the subjecto i procedure would provide for the detection of; electrical-faultsiand i ignition of cables under high temperature conditions, it would noti j determine whether the insulation resistance of an'instrumentationicable-a has degraded sufficiently to affect its ' safety related1 function lduringia.- fire. Therefore, Supplement I to GL 86-10 -includes; additional: tests to + evaluate cable insulation degradation and' fully assess functionality. 4; IX. Winston and Strawn letter of August 20,1993-(Attachment.9? COMMENT 1 - Backfit o .Winston and-Strawn contended that Supplement,1 to GL 86-10 should-go i 4 through the backfit process. Their basis for this claim =is based'on the. following:. 1 f . ilI L li[ ifb u e
m _~ s. +, "The NRC has indicated in preOous issuances' that the fire endurance. tests 'on which many licensees relied to justify installations of. Thermo-Lag.in its plants may not be adequate. The language of the draft. ~ supplement suggests that tests-conducted in the future (e.g., the NUMARC - fire test program) will be evaluated against the new criteria. The i results of such future tests' apparently will be used,- however, to assure the adequacy of installations and testing performed by numerus licensees in the past. The use of the proposed new criteria to validate existing'. installations and previous tests would appear to present a.backfitting concerns and to require staff performance of a backfitting analysis'per section 50.109(a)(3)." STAFF RESPONSE Supplement I to GL 86-10 clarifies ' existing fire endurance _ test guidance ~ specified in GL 86-10. It does not effect previous raceway fire barrier system tests performed to this previous GL 86-10 guidance. The supplement will be used by the NRC staff as review guidance to evaluate future fire barrier tests intended to demonstrate compliance with existing NRC rules and regulations and to review the adequacy of fire barrier systems proposed by license applicants. Therefore,.since the staff will use this position to evaluate future fire barrier testing 1 programs, the staff concluded therefore, that this change in staff position is not a backfit. COMMENT 2 - Radiant Enerav Heat Shields "Both the Branch Technical Position CMEB 9.5-1 and Generic Letter. 86-l'0, indicate that a radiant energy shield that may not strictly meet the. definition of noncombustible (see Section B.4 of CMEB 9.5-1) is acceptable if it has a fire rating of one-half hour." STAFF RESPONSE There is no technical basis for the contention that a radiant energy. shield does not have to meet the definition of nonccmbustible if it~has a fire rating of one-half hour. The Standard Review Plan (Section 9.5.1, " Fire Protection Program," Section B.4) defines a noncombustible material as one which in the form in which it is used and under the conditions anticipated, will not. ignite, burn, support combustion, or release flammable. vapors when subjected to fire or heat. SRP Section C.7.a(1)(b), specifies the separation of cables, equipment and associated nonsafety circuits of redundant trains by a noncombustible radiant energy shield having a minimum fire rating of nne-half hour. GL 86-10 (Section 3.7, " Radiant Energy Shield," question 3.7.1, " Fire Rating") states "In some cases, where the penetrations were grouped by division, shields were placed - between the divisions so that radiant energy from'a fire involving'the cables of one division would not degrade or ignite the cables lof the. other divisions. These shields also directed the convective energy from - the fire away from the surviving division. These shields were usually
y 3. - constructed.of \\-inch marinite board in a metal frame'.- Appendix R, Section III.G.f refers. to these shields. as "a noncombustible radiant energy shield." The guidelines in BTP CMEB 9.5-1, Section C.7.a(1)(b),. indicate-that these shields should have.a fire rating'of % hour. It is the staff's view that any material with a % hour fire rating-should be capable of performing the required function." Since GL 86-10 ; identified several examples of noncombustible materials, the. staff concluded that this response was focused on the.need for the shield to have a fire resistive rating. The response also provided performance criteria by: stating that radiant energy shields direct convective energy away from-the object being protected. Clearly, a combustible material would not be capable of performing this function, s [_0.MMENT 3 - Reference to Accendix R 0 Winston and Strawn requested that a quotation from'the Appendix R final' rule making be deleted. The statement quoted is "If plant specific conditions preclude the installation of a 3-hour fire barrier to separate the redundant trains a 1-hour fire barrier and' automatic' fire suppression- [and detection) system for each redundant train will-be considered the equivalent of a 3-hour barrier." Winston and Strawn contended that this-quote establishes a hierarchy of the options for protecting safe shutdown capability within the same fire area. STAFF RESPONSE In the staff's view, this statement substantiates the basis for establishing the equivalency of the fire protection options specified in Appendix R. However, to clarify the intent of this statement the ' staff added the following statement to Enclosure A, Section V, of Supplement I to GL 86-10: " Appendix R to 10 CFR Part 50, Section III.G, Fire Protection of Safe Shutdown Capability. provides, what' the NRC views as, equivalent means. for ensuring that one safe shutdown train is free of fire damage." X. William A. Thue letter dated August 17, 199? (Attachment 10) l COMMENT 1 - Cable Functionality Testino "These tests must be conducted in a laboratory that has high temperature testing facilities - not a cable laboratory. Any attempt to do both temperature testing and electrical testing while the test is in progress is impractical, unsafe and will not prove nor disprove the validity of the cable condition." STAFF RESPONSE S It is the staff position, as documented in Supplement'l to GL 86-10 and-in its responses to previous comments on cable functionality, that the tests and analyses specified in the supplement are valid for demonstrating cable functionality for deviating barrier conditions. 'The t
a 7(. N hj e nuclear power industry "and national test laboratories have performed-. numerous environmental qualification (EQ)itests of cables which' involved. simultaneous monitoring of electrical: parameters (e.g... insulation k resistance) under high temperature (e.g., LOCA: temperature conditions).- The staff did not change its proposed staff position or acceptance criteria'in response to this comment. l COMMENT 2 - Use of ' Conductor Temperature "For the past 100+ years, cable engineers have used the conductor'. temperature to predict performance - not the jacket temperature. Some: temperature readings must be made with thermocouples on the conductor'in' the mass. This negates any electrical testing 'on those runs." HAFF RESPONSE Conductor temperature is applicable to cable qualification testing. However, cable qualification is not the intent of the fire barrier acceptance criteria. The purpose of the cable functionality tests specified in the criteria is to provide performance data to assess deviating conditions if the fire hac-ier acceptance criteria are-not met' Supplement I to GL 86-10 does not replace or substitute for cable qualification tests. The staff did not change its proposed staff position or acceptance criteria in response to this comment. COMMENT 3 - Test Procedures " Electrical tests must be made on cable that has two properly terminated ends. This means that both ends must be outside the fire barrier. The only way to assure their still. being good after the fire is to make them as far away as practical from the heat source. To do. these. electrical-tests immediately after the' end of the test (presumably just after the - hose stream), requires the terminations be clean." "Many laboratories do not look kindly on having. guests.in the vicinity of even the cold side during such tests. This forces'one to put long enough ends on the cables to reach some satisfactory electrical test. position. 1 These long cable ends are now subject to mechanical damage that has i nothing to do with the purpose of the test. Additionally the test instrument must be in a cool environment to produce accurate' results. Long test leads also result in inaccurate readings." "Any attempt to terminate.the cables after the test can lead to misleading results. Mechanical forces that may be needed for terminating l - 1 procedures could easily mask out the successful passing of the test. This presumes that some degradation of the cable has been noticed that would make an electrical test necessary." STAFF RESPONSE The cable functionality tests specified in Supplement l' to GL 85-10 are typical tests conducted for maintenance purposes in nuclear power plants. ,+
-o pc e-s. 6., Tests. recently perfornedt by TU Electric Company. for CPSES have-demonstrated that' cable: lead length, cleanliness, location' of test - equipment, and potential for mechanical damage are not-technical problems, during' fire tests conducted'in accordance with good! engineering and laboratory practices and the acceptance criteria'specifiedLinLthe? supplement. T;ie staff did not change its proposed staff position ~orz acceptance criteria in response to this comment. COMMENT 4 - Mecoer Tests. m "Only modest megger tests should be used if any electrical tests are' made-after the fire test. High voltage de tests are presently under. careful. scrutiny by the EPRI, the Insulated. conductors Committee of.the IEEE... L It is strongly suggested that de tests are of a_ questionable value in meeting the stated objective to provide ' assurance that the cable.will. ~ withstand the applied voltage during and after the fire...' ~The concern' here is not that the cable will fail the test, but that the test will-fail the good cable." "This radical change in electrical monitoring the cable during and/or-after.these barrier fire tests should not be instigated until a workshop or other agreement of the cable engineering community has been reached. There is considerable personal concern that the cable engineers may~not-be remotely aware of these proposed changes." STAFF RESPONSE It is the staff position, as documented in Supplement.I' to GL '86-10 and 1'9 in its responses to previous comments on cable-functionality,- that' the tests and analyses specified in the supplement are valid for. a demonstrating cable functionality for barrier deviations. The-cabler i functionality tests specified in the supplement 1are typical tests conducted for maintenance purposes in nuclear power plants. The staff. does not believe'that the tests are a radical change in ' electrical monitoring. Tests recently performed by TU Electric Company for CPSES - demonstrated that the Megger test methods and the application of the test results specified in the supplement are valid for obtaining functionality data needed to assess barrier deviations. The staff did not change its proposed staff position or acceptance criteria in response to this comment. XI. Ohio Citizens for Responsible Energy, Inc. Letter of August 22, 1993-i (Attachment 11) COMMENT 1 - Combustibility "The NRC should strictly prohibit the use of fire barrier materials. which are combustible. A fire barrier is of little'use if it itself burns." n s e i a s
y ey T. f 4 p' JF RESPONSE The'NRC staff position on combustibility relative to Supplement I to GL 86-10-is provided in the staff response to Comment IV.1, (page 15). [QMMENT 2 - Hose Stream Test Methods "The proposed criteria wnuld permit the use of fog. nozzle test instead of solid hose stream test. This. is unacceptable; The solid stream is more-severe, and more likely to be used in fighting an actual fire. The fire barrier must withstand the most severe conditions which may be-encountered." STAFF RESPONSE The bases for the NRC staff position on hose stream testing are provided in the staff response to Comment.I.1, page 1. XII. Tennessee Valley Authority Letter of August 23, 1993 (Attachment 12) COMMENT 1 - Fire Tests of Emoty Enclosures \\ TVA recommended that the fire endurance testing criteria proposed by supplement to GL 86-10 be changed to eliminate cables in the raceway during the fire endurance test and that the internal cable tray or: raceway temperature profile, as measured by a bare copper' conductor, be used to evaluate the functionality of cables that are going to be enclosed within in-plant fire barriers. STAFF RESPONSE The staff agrees with the comment. Testing empty enclosure:.is conservative =in that the fire barrier system is not influenced by the heat sink provided by cables. Therefore, the staff added.a. flow chart to the test acceptance criteria to address testing fire barrier. systems '. i using empty raceway enclosures. The staff also revised Supplement I of-GL 86-10 to specify a methodology for fire' testing racetov fire barrier systems without cables, for air oven cable functionality-cesting, and for performing engineering analysis using other cable thermal performance data to demonstrate that the cables can fur.ction in the temperature. environment observed during the fire test if the temperature profile exceeds the fire test temperature rise criterion and revised Supplement 1 to GL 86-10 to include provisions for testing fire barrier systems without cables. The staff also agrees,- for those fire barrier systems that exceed the cable tray or racecay barrier surface temperature acceptance criteria, that the internal temperature profile, as determined by the instrumented bare copper conductor, can be used in air oven testing when evaluating the functionality of plant-specific cable'; The staff incorporated the following guidance into Section V of the fire endurance testing acceptance criteria: 4 5
( F>. Thermocouple Placement - Test Specimens Without CablN The following are acceptable. thermocouple placements for determiningL the - thermal performance of raceway-or cable tray fire barrier systems that do A not contain cables: Conduits - The temperature rise of the unexposed -surface' ofia-fire barrier system installed on a conduit shall be measured by placing: thermocouples every 152 mm [6-inches] on'the' exterior conduit 1 surface, between the conduit and the unexposed surface of the' fire barrier material. These thermocouples shall be. attached to the - exterior conduit surface opposite of the test deck and closest to. a the furnace fire source. Tne internal raceway temperatures 'shall be measured by a stranded AWG 8 bare copper conductor routed through o the entire length of the conduit system with thermocouples installed every 152 mm [6-inches] along the length of the copper: conductor. Thermocouples shall also be placed immediately. adjacent to. all j structural members, supports, and barrier penetrations. Cable Trays - The temperature rise on the unexposed surface.of a fire barrier system installed on a cable tray'shall be measured by, i placing thermocouples every 152 mm [6-inches] on the exterior surface of each tray side rails between the side rail and the fire-barrier material. Internal raceway temperatures-shall be measured by a stranded AWG 8 bare copper conductor' routed on the~ top _of.the cable tray rungs along the entire length and down the-longitudinal center of the cable tray run with thermocouples installed.every 152 mm [6-inches] along the length of the copper conductor. Thermocouples shall be placed immediately adjacent to ~all. structural- -i members, supports, and barrier penetrations. Junction Boxes (JB) - The temperature rise.on the. unexposed surface of a fire barrier system installed on junction boxes shall be-measured by placing thermocouples on either the. inside or the outside of each JB surface. Each JB surface or face shall have'a minimum of one thermocouple, located at its geometric ' center. -In - addition, one thermocouple shall be installed for every one square 't foot of JB swface area. These thermocouples shall be located at the geometric centers of the one square foot areas. At least one thermocouple shall also be placed within 25 mm [1-inch) of each penetration connector / interface. Airdrops - The internal airdrop temperatures shall be measured by a i stranded AWG 8 bare copper _ conductor routed inside and along the entire length of the airdrop system with thermocouples installed - r every 152 mm [6-inches] along the length of-the copper conductor. The copper conductor shall be in close proximity with the unexposed surface of the fire barrier material. Thermocouples shall also. be placed immediately adjacent to'all supports and penetrations. Temperature conditions on the unexposed surfaces of the fire barrier. material during the fire test will be determined by averaging the J t 4 ^
- }
~
r . temperatures measured by the thermocouples installed in or-on the-raceway. In determining these temperature conditions, the thermocouples ~ measuring similar areas of the fire. barrier shall. be averaged together. J Acceptance will be based -on the individual ' averages. The following-- method of' averaging shall be followed: Conduits - The thermocouples applied to the outside metal-surface of.. the conduit shall be averaged together. Cable Trays - The thermocouples on each cable tray. side rail'shall be averaged separately. For example, thermocouples placed on~one side rail will be averaged separately from the other side rail.. In addition, the temperature conditions measured-by thermocouples on the bare copper conductor shall be averaged separately from the side rails. Junction Boxes - For JBs that have only one thermocouple.on each JB' t surface, the individual JB surface thermocouples shall-be averaged together. For JBs that have more that one thermocouple on each JB; surface, the thermocouples on the individual JB surfaces shall be ~ averaged together. Airdrops - The thermocouples placed on the copper conductor within the airdrop fire barrier shall be averaged together. The average of any thermocouple group shall not exceed 4139 *C. [250 f*F) above the initial temperature within the fire barrier test specimen at the onset of the fire endurance test. In addition, the temperature-of each individual thermocouple will be evaluated. Individual thermocouple conditions shall not exceed the 139 *C [250 *F) temperature rise by more. than 30 percent. If a fire barrier test specimen without cables does not meet the average or maximum single point temperature criteria, then-the internal' raceway. temperature j.ofile as measured by the instrumented bare copper conductors during the fire exposure can be used to assess cable functionality through air oven testing of plant-specific cable types and construction. COMMENT 2 - Cable Functionality "UL Subject 1724, Appendix B, provides a methodology to use the temperature profile obtained from an instrumented bare copper-wire to qualify the unique cable sizes and types intended for use in specific-fire barrier enclosures. TVA considers that testing'in accordance with UL Subject 1724, Appendix-B, more accurately demonstrates cable functionality at elevated temperatures than int?rmittent electrical tests performed on selected cables during or after a fire endurance test. It is also more objective than reliance on a visual inspection for signs of-degraded conditions.. NRC's criteria should be expanded to permit acceptance of fire barrier enclosures for which internal temperatures.
T 'k.4 rise greater than_139 *C"on 'the basis:of successful performance _ of tests in.accordance with UL Subject 1724,-Appendix B." STAFF RESPONSE The staff agrees with the comment. See response.to Comment-VIII.3, (page 23). COMMENT 3 - Thermocouples on Cables TVA cominented on the placement of thermocouples on cables that ~are included in the fire barrier system during the fire test. TVA contends ~
- i that since the proposed NRC fire endurance test acceptance criteria identifies these thermocouples to be used for " engineering purposes" 4
1 only, that its placement should be left to the discretion of the. licensee. STAFF RESPONSE ~ The staff agrees with the comment and deleted the requirement.to instrument test specimen cables from Supplement I to GL 86-10. COMMENT 4 - Construction of Bare Cooper Conductor TVA commented on the size of the bare copper conductor used for measuring' internal temperatures of-the -fire barrier system and recommended that the-construction of the bare copper conductor (i.e., solid or stranded), be, j specified in the criteria. l STAFF RESPONSE The staff agrees with the comment-and revised Supplement I to GL 86-10' appropriately. 7j COMMENT 5 - Internal Raceway Temoerature Measurement TVA recommended that the bare copper conductor be used only for determining the internal raceway temperature profile during the fire endurance test. In addition', TVA recommends that the temperature of the lower external surface of a cable tray be determined by attaching the thermocouples directly to the center of the underd da af nach cable tray rung. STAFF RESPONSE The staff agrees with the comment for test specimens that'do not contain cables and revised Supplement I to GL 86-10 to-incorporate provisions for 3 the use of a bare copper conductor _ to determine the internal raceway temperature profiles during the fire exposure in 'such specimens._. The ' staff also concluded that the method _specified in Supplement.I to .GL 86-10 for determining the lower external cable tray surface temperatures is. technically equivalent to that recommended by TVA.
+, , w .L j COMMENT 6-TVA recommended that the acceptance criteria specify th' particular-e location of the thermocouples placed on the externalisurface of conduit. ti STAFF RESPONSE a The staff agrees with this comment an'd revised Supplement'l to GL 86-10 appropriately. See the staff response to Comment XII.1, (page 28). XIII. American Nuclear Insurers (ANI) letter of August 16,' 1993 (Attachment 13) COMMENT 1 - References to ANI Bulletin 5(79) ANI requested that references to ANI Information Bustin 5(79), "ANI/MAERP Standard Fire Endurance Test Method to Qualify a Protective Envelope for Class IE Electrical Circuits" identify the document as being issued for ANI/MAERP insurance purposes only. STAFF RESPONSE The staff agrees with the comment and revised Supplement 1 to GL 86-10 appropriately. COMMENT 2 - Incorrect Date Reference ANI identified an incorrect ANI document date reference in the proposed supplement to GL 86-10. STAFF RESPONSE The staff agrees with the comment and corrected the date of.the referenced ANI document. XIV. Consumers Power Company letter of August 23, 1993 (Attachment 14) COMMENT 1 - Use of the Term Fire Barrier Consumers Power commented on the term fire barrier. "The proposed supplement uses the term fire barrier and raceway fire barrier throughout-l the document. This results in _ confusion 'as to what is actually being ~ described and discussed. Good definitions are provided for these terms in the definition'section of the supplement. We believe that. confusion can be reduced by using the terms consistently." STAFF RESPONSE The staff agrees with the comment and revised Supplement I to GL 86-101 appropriately. ,~
e y e ' COMMENT 2 - Thermocouple Placement "The purpose of a raceway fire barrier'is = to protect the cables, to keep: l them free from fire damage, and to ensure its. functionality...Thus, to. have accurate and realistic data from the cables,- thermocouples should. be placed on the-cables. Placing the thermocouples on the raceway. surface. ~ is ultraconservative and would not provide accurate data on the. exposure to the cables as the raceway itself provides-' protection to.the cables." STAFF RESPONSE U The staff agrees that the purpose of a raceway fire barrier is to protect the cables, to keep them free from fire damage, and to ensure their functionality. However, in the staff's opinion, fire barrier: o qualification is based on demonstrating by.a standard fire ' endurance test-that the fire barrier system is capable of limiting temperature rise on - the unexposed side of the barrier. This staff position was stated.in GL 86-10 and is not changed by Supplement 1 to GL 86-10. (The. supplement, also provides the staff position on measuring temperatures from cable-insulation.) i The staff did not change its proposed staff position or acceptance criteria in response to this comment. g q -XV. Entergy Operations, Inc. letter of August 20,1993.(Attachment 15) COMMENT 1 - Temperature Conversions Entergy Operations stated that the temperature conversions, Fahrenheit to Celsius, appear to be incorrect. For example, 250 *F should be 121- *C not 139 *C. STAFF RESPONSE The subject temperatures are expressed in terms of a' temperature rise, { not absolute temperatures. In this context, the temperature. conversions; are correct. The staff did not change its proposed staff position or acceptance criteria in response to this comment. COMMENT 2 - Types of Barriers Covered by the Acceptance Criteria: 1 Entergy Operations stated that the scope in the purpose section-of the proposed supplement to GL 86-10 is unclear and that-it encompasses all types'of fire tests. Entergy Operations also stated that' the proposed supplement to GL 86-10' contains a discussion about the acceptability of fire doors and fire ~ dampers which have been tested and listed by an approved fire testing i laboratory. Entergy Operations recommended that this discussion-be= 1 . expanded to. include penetration seal systems, structural-ste'l~ systems,- j e-and fire wall assemblies. q i
ac: s. E
- i. 1
-[ STAFF RESPONSE. l Supplement I to GL 86-10 does not cover all types of fire tests. Thej purpose of'the supplement is to specify fire test. methods andf acceptance criteria for qualifying fire barrier systems used;to ' separate safe-shutdown components within the same fire area. Section-IV:of the-acceptance criteria specifies fire endurance test methods ~and criteria for fire barrier walls, floors,. ceilings, and equipment enclosures. Section V of the acceptance criteria specifies Lfire test methods and. criteria for raceway fire barrier systems. The staff discussed fire doors and dampers for purposes of' clarification. Including penetration seals, structural steel and listed wall _ assemblies-would not clarify or provide additional guidance-to that which exists in current NRC fire protection program guidance documents. COMMENT 3 - Penetration Seals "The last paragraph of Section IV should be revised to include ASTM E814 as a guidance document to be consulted with regard to. construction, i materials, and thermocouple placement. This is appropriate due to the. discussion in the preceding paragraph which references penetration se al s. " STAFF RESPONSE As discussed in the staff response to Comment XV.2, (page'33), Supplement I to GL 86-10 does not address penetration seals. NUREG-0800, 's Standard Review Plan (SRP), Section-9.5.1, " Fire Protection for Nuclear Power Plants," specifies fire endurance testing acceptance criteria and guidance for penetration seals. (Nationally recognized testing? standards, such as ASTM E-814, which establish a equivalent level of; fire barrier penetration seal performance, 'would be reviewed by the ~ staff for acceptability on a case-by-case basis.) The staff considers the SRP criteria for penetration seals adequate. Additional guidance is not needed. COMMENT 4 - Thermocouple Placement Entergy Operations recommended that a tolerance of \\ inch be allowed to for the installation of thermocouples on test specimens. _ -Entergy Operations also requested further clarification on the placement of the-instrumented bare copper thermocouples on the cabla' trays. STAFF RESPONSE i The staff included a thermocouple installation tolerance into Supplement I to GL 86-10. The staff reviewed the guidance for' placement on the instrumented bare copper conductors and concluded that additional clarification was not warranted. l 1
.m 4 fj Lv y-b ~ ~ COMMENT 5 - Enoineerina Thermocouples-Entergy Operations stated that the placement of ' engineering thermocouples.- on the cables should be left-to the discretion of the licensee or' the testing laboratory. STAFF RFSPONSE The. staff agrees with this comment and-revised Supplement 1 tb GL.86-10 appropriately. COMMENT 6 - Terminoloav The terms fire barrier and raceway fire barriers are used synonymously. For clarity, Entergy Operations recommended that the term raceway fire barrier be used throughout the document. STAFF RESPONSE The staff revised Supplement I to GL 86-10 to clarify the term fire barrier. COMMENT 7 - Incorrect Metric Conversion Entergy operations identified an improper metric conversion for the 1% inch fog nozzle.. STAFF RESPONSE The staff corrected the metric conversion. [_0MMENT Penetration Seals 0 Entergy Operations recommended that Section VIII reference ASTM E814, y " Standard Test Method for Fire Test of Through Penetration' Fire Stops." STAFF RESPONSE The staff disagrees with the recommendation. See the staff response to-Comment XV.2 (page 33) and Comment XV.3, (page 34). COMMENT 9 - Use of Previous Test Results Entergy Opera' tions requested clarification for the following potential future situations: A. A previously approved fire barrier system is. removed during a modification and then replaced without change, or.with insignificant changes. t j. l' c.k
c 3i 3i g g B. Amodificationhasbeenm'adeandthefirebarriersystemaddb'has L not been previously used at that plant, but previously approved tests (conducted prior to GL 86-10, Supplement 1)-for the material and configuration can be obtained fromLanother. utility. STAFF RESPONSE A. The fire endurance testing acceptance criteria specified in Supplement 1 to GL 86-10 will be used by the NRC staff to review future qualification' fire tests for fire barriers used to separate redundant safe shutdown trains within the same f area. Therefore, the criteria, in and of themselves,. ' effect previous NRC approvals. The adequacy of previ barrier-qualification tests will be reviewed by the staff against either. the conditions of a previous plant-specific NRC approval or the fire barrier guidance provided in GL 86-10. Specific future situations will be reviewed by the staff on a case-by-case basis. B. Responsibility for determining whether or not existing fire barrier qualification tests (regardless of their source) can be used as the' basis for installing a 'particular fire barrier system in a plant-rests with the individual licensee. The adequacy cf previous fire barrier qualification tests will be reviewed by -the' staff. against. either-the. conditions of a previous plant-specific NRC approval or the fire barrier guidance provided in GL 86-10. Specific future situations will be reviewed by the staff on a case-by-case basis. XVI. Philadelphia Electric Company letter of August '23,1993 (Attachment 16) COMMENT 1 - Measurement of Temnerature Rise ] Philadelphia Electric requested that the acceptance criteria clarify the thermocouple placement for determining the temperature rise by. adding "as measured on the exterior surface of the electrical raceway or component requiring protection". STAFF RESPONSE i It is the staff position that during the fire endurance qualification-test, the transmission of heat through the barrier should be measured on the unexposed side of the fire barrier material. For raceway systems,. the temperature rise can be measured on the exterior surface of-the raceway since the raceway is in close proximity to the unexposed side.of-the barrier material. For other components protected by free standing fire barrier enclosures, measurement of the temperature on the exterior-surface of the-component may not be an acceptable means of assessing the temperature of the unexposed side of the barrier. Supplement I to GL 86-10 reflects this.
[R-K ai R.. bk . 37.
- 1 COMMENT Cable Damace Definition =
Philadelphia Electric recommended that " examples of cable degradation are: exposed, degraded, or discolored ' conductor insulation." _ Philadelphia-Electric stated that' cable' jackets can sustain ~ damage while.the underlying conductor insulation remains damage free, therefore,'not adversely effecting the function of the cable. ~' STAFF RESPONSE The staff considers cable jacket discoloration fire" damage. The function' of the fire barrier is to maintain the protected component free of. fire damage. Therefore, cable jackets that are discolored by heat are not free of fire damage. The staff did not change its proposed staff. - 4 position or acceptance criteria in' response to this comment. COMMENT 3 - Temperature Specification Convention Philadelphia Electric recommended that the convention used to identify temperature rise be A 139 *C (A 250 *F) and end_ point temperature as 121 *C (250 *F). STAFF RESPONSE The staff reviewed Supplement I to GL 86-10 and found-the specified temperatures properly qualified by the text. The_ staff did not change its proposed staff position.or acceptance criteria in response.to'this-comment. COMMENT 4 - Thermocouple Placement Philadelphia Electric recommended that the thermocouple placement a criterion proposed by NUMARC for the industry test' program be used instead of the criterion recommended by the supplement to GL 86-10. STAFF RESPONSE The staff disagrees with the comment. The bases for the thermocouple placement criteria specified in Supplement I to GL 86-10 is provided in the supplement and under the staff responses to Comments III.4 (page 12),. XII.1 (page 28), XII.3 (page 31), XII.5 (page 31), XIV.2 (page'32), and- ~ XVI.1 (page 36) and Comment XVII.3 (page 39). t: COMMENT 5 - Review of In-Plant Barriers Philadelphia Electric indicated that guidance is needed on how the NRC' will review installed assemblies not exactly matching tested configurations. i i
y .g STAFF RESPONSE The intent of Supplement I to GL 86-10 is to provide' guidance for performing future fire test programs. The objective of a fire test-program is. to develop and' test specimens that bound the sizes'and types of raceway configurations installed in the plant. In Addition, the test - t program should use fire barrier. installation techniques.that will be used 1 to construct the in-plant fire barrier systems. The NRC recognizes that.. all possible in-plant fire barrier configurations cannot be tested. Therefore, for field conditions which impact the installation-of a fire- + barrier, an engineering evaluation should be performed. - This engineering evaluation should confirm that the configuration under censideration is within the bounds of the test program. GL 86-10 provides guidance forl assessing variations between tested' fire barrier configurations and installed configurations. The staff did not change its proposed staff position or acceptance criteria in response to this comment. COMMENT 6 - Com_hustibility Philadelphia Electric requested that the NRC requirements that fire-barrier materials used as radiant energy heat shields.and to-establish. combustible free' zones be revised to allow deterministic. fire modeling to identify whether the material will function-as designed. STAFF RESPONSE NRC requirements for radiant energy heat shield, licensee practice of enclosing combustibles to create combustible-free zones, and deterministic fire modeling are not the subjects of Supplement.1 tot GL 86-10. Therefore, the staff did not change.its. proposed staff. position or acceptance criteria in response to this comment.. Additional information fire barrier combustibility is provided'in the staff. response to Comment IV.1, (page 15). 1 XVII. NUMARC letter of August 23, 1993 (Attachment 17) COMMENT I - Comparison of Suoplemental Guidance to Oriainal ' Guidance NUMARC stated that the fire test and cable functionality criteria proposed by the proposed supplement to GL B6-10-is more conservative than those currently specified in GL 86-10. Examples are: "1. The requirements for evaluation of tested configurations with respect to installed configurations; Generic Letter 86-10' required only that-continuity of the fire barrier,: thickness of the barrier, nature of.the support assembly, and end use application be considered. The proposed supplement'would. require evaluation of the - t workmanship, and details such as dimensions of parts. This.will' result in the need for many more tests to qualify a given number:of diverse configurations than would be the case under the original-Generic Letter-86-10 requirements." ? .g ? N,. _ _ _
w , "2. The requirements. for cable functionality' verification' would be r changed from simple low voltage continuity testing to much more rigorous ~ testing, including Megger, and hi-pot testing, and consideration of initial cable operating temperature in the cab 1'e-evaluation process. This process is not only resource intensive in performing the tests, but could also result in disqualification of-cable type previously found acceptable for a given time temperature-exposure." STAFF RESPONSE 1. Generic Letter 86-10 ' Imp %nentation of Fire Protection Requirements," esta'.13 4 that National Fire Protection ~ Association-(NFPA) Standard 251, "'if.ndard Methods of Fire Tests of Building - Construction and Materials," provided the basis for the staff position' for qualification testing of raceway fire barriers. NFPA 251 specifies the evaluation of the workmanship and details such as dimensions of parts. This original position is not changed by Supplement I to GL 86-10. Staff guidance for evaluating tested configurations with respect to installed configurations from GL 86-10 (that the continuity of the fire barrier, thickness of. the barrier, nature of the support assembly, and end use. application be - considered), is also not changed by the supplement. 2. GL 86-10 did not specify criteria for evaluating cable functionality. In Supplement I to GL 86-10, the general fire.. barrier acceptance criteria guidance established by GL 86-10, were adapted for fire barrier systems used to separate safe shutdown trains within the same fire area. Supplement I to GL 86-10, establishes a fire resistive performance' acceptance criteria for raceway fire barrier systems that is equivalent to that required by Chapter 7 of NFPA 251 for non-bearing fire barrier partitions or walls. The need to assess cable functionality is only necessary-when the fire barrier system has not adequately performed its fire resistive function during the fire endurance test and the licensee proposes to justify the deviating condition. The purpose of-the functionality tests is to justify the observed deviations in fire barrier performance. The staff did not change its proposed staff position or acceptance criteria in response to these comments. COMMENT 2 - Backfit Analysis NUMARC stated that a backfit analysis should be performed to the requirements of 10 CFR 50.109, to demonstrate that the conservatisms inherent in the other aspects of Appendix R, as they relate to the' proposed augmented requirements for fire barrier testing and acceptance. NUMARC requests that this analysis be performed as~ part of the process of 1 finalization of the proposed generic letter supplement, and should not be deferred to later plant-specific-applications. i ar
] ( V STAFF RESPONSE The staff. addressed backfit analysis in its response to Comment IX.1, k (page 23) COMMENT 3 - Temperature Criterion 4 4 NUMARC believes that the basic premise for the temperature acceptance. criteria should relate to cable temperatures,-as measured-by bare copper: conductors in contact with the cables, or on the raceway. surfaces in direct contact with the cables, rather than cold side barrier-temperatures. NUMARC: further contends, that' the use ~of cold' side L temperature, as originally specified in GL 86-10,- is a-result 'of application of the ASTM E-119 Standard to cable raceway testing. Accordingly, NUMARC contends that this standard was not. intended for. application to cable raceways, but was intended for non load bearing walls that may be in direct contact with combustible material. In addition, NUMARC indicated that'no consensus fire test standard has previously existed for cable tray raceway protection. ASTM Subcommittee E5.11 has devoted considerable effort in the past year to develop such a standard. NUMARC indicated that draft 8 of this proposed standard, provides for the use of the bare conductor for measurement of temperatures in cable tray systems and is' consistent with the proposed NRC approach in many respects. This proposed draft of the' ASTM standard. provides for placement of the lower ~ central copper conductor above the cable tray rungs, consistent with the NUMARC position. STAFF RESPONSE The staff agrees that the draft standard proposed by ASTM Subcommittee E5.11, " Standard Test Methods for Fire Tests of Fire Resistive Barrier-Systems for Electrical System Components," Draft 13, August 27, 1993,- establishes a sound technical basis for assessing the thermal. performance-of raceway fire barrier systems. This proposed ASTM standard specifies that fire tests of raceway fire barrier systems be performed on test. specimens that do not contain cables. In addition,.this. standard uses an instrumented bare copper conductor inside the raceway to~ determine the internal temperature rise within the fire barrier system during the fire exposure. (This instrumented bare copper conductor is'in addition to~the cable tray side rail surface thermocouples.) The instrumented copper. conductor is installed down the longitudinal center of the cable tray attached to the top of the cable tray rungs. Under this approach, there is no thermal mass (cable fill) to influence the thermal performance of-the fire barrier system and the temperature profile measured by the bare. copper conductor more accurately reflects.the thermal performance-of the fire barrier system during the fire test. The staff revised Supplement 1 to GL 86-10 to incorporate a similar test method. It is the NRC staff position that this is the preferred test method forf qualifying fire barriers to be used for protecting various cable
. w ~ J. / +s s' 'I k I 41_. 1 insulation' material; types. Under this test method,;iffa fire barrierf -system without;a cable fillipassed the_ thermal and barrier condition? l _ ' criteria, the fire barrier. configuration could be applied to similarlyf 1 -designed racewayJsystems;containing any of the various.cableLtypeseusedL f in the nuclear industry., e
- s COMMENT ~4 - Cable Thermocouples
~ ] p o NUMARC. stated that the inclusion of cable thermocouples for." engineering:' information" is not justified. m u STAFF RESPONSE @[ The staff agrees with the comment and revised Supplement I to-GL 86-10: f appropriately. t COMMENT 5 - Combustibility-
- e "The ASTM E-136 method for determining material combustibilityLis butio~ne; method available in defining a material as a " combustible material."?In-44 the same vein, the ASTM E-84 test for flame spread.is.but.one method i
available in defining a material as a flame spread hazard. Both these: methods are:" pass / fail"-standards with the' definition of " pass / fail" 1 having only " standard" rather than " specific" relationship.to'actua1L plant conditions. These standards do.not allow the. licensee. thel.. opportunity to evaluate plant-specific situatio'ns,toLdetermine if there . is' any actual impact on -safe plant shutdo_wn.1 Consideration of;theiformi in which the materia 1Lis used and the conditions anticipated:in'the! plant, as provided for in the definition of noncombustible materials contained in Section III,- Definitions,:of Enclosure I to theLproposed, ']J generic letter supplement, cannot-be accomplished with the use"offthesel standards. These issues re better addressed by testing to ASTM'E-1321f s; and E-1354." STAFF RESPONSE The NRC staff position on combustibility is provided;in its response to' -L Comment IV.1, (page 15). COMMENT 6 - Cable Functionality I "The methods discussed in the NRC proposed 1 approach relate toltesting ofi cables during and after actual. fire.' tests-of the specific cables. Given ' the broad diversity of cable types, siz'es,- brands, = etc., it11s l impractical to assume that fire tests would be conducted: encompassing 1thet.. l cable. types in.use. -A more practical approach is to generate; time temperature (T-t) data from genericite. sting.of. protected raceway 1. configurations, and then to apply these 'results to Linstalled cable typess (to the extent that the-temperatures are in excess of.the 325 "F3 criterion). The;NRC= position shouldLallow for this< optional approach.=
- There are two ways this. approach can be' accomplished:
~ <y g ; i4 m h 5 ~ ~
s , g, + /c r,e g ',7.; y4, 9, /g / [$,4 4, A 4p IMAGE EVALUATION \\kg,1 ' Ohf* TEST TARGET (MT-3) k", kb'Y .gy(,,+g l.0 M L 03? ;;2.2 L ogss .; y t: :. c lpll 2.0 l,l bm ll 1.8 L_ 1.25 1.4
- iL1.6ll __
l -= w - -- 150mm 4 6" s %'?/' A 4'+ //A+ A 4:,,g+ //% v gu, i, c ~ t !} ,6 m, v m V' ~ /,% r ,m y I
1' i J lo ,p & i, < ; q' 9 y, n ,~ s IMAGE EVALUATION /f S @, O \\///7 1[ ^$f' TEST TARGET (MT-3) $ ',f,' je, /(4, th [ W/,0 v v I.O M L: "m inse l,l ,4 illba=a 1.8 h 1.25 1.4 t l _1.6_ 4 -- 150mm 4-6" (( s' +($hpfs\\\\\\
- IIjP
%n($)f b y,, y 4Q 4 e oh ,g-ee 4
d .e
- < '+
(g O IMAGE EVALUATION c% //// TEST TARGET (MT-3) / J >?? ~ Q, s //// .4 g, .g y 1.0 E22 l,l lLi, 2.0 i52:! 3 I!lll 1.8 % ++ jlklli 1.2 5 !!ll !.4 cil 1.6 i ame em= l
15 0 m m --
6" g ,' [ ) j L . %gh//4 '\\ ? $y //4 + / ,g// m, y j, g // -Q ~ aEi , _njj
i fO z$" j e , %e% .C., y / [;';[ff 4(g i IMAGE EVALUATION ~ 4 //o//7'1 49 TEST TARGET (MT-3) Vp 4y, 4i? tc l.0 M jfll2.0 l,l IEE;== !! l.8 ume 1.25 ll1.4 la 1.6 itj== n-4 150mm 4.____..__._ 6"
- [$$'
\\ f hf)? fp [\\ > <p " 4 %)'4-6Q l;//h' $r l:y,// 4 / 4, ,;n ~ y+w o /, ogg ( c_-_-
4 ~ } -m e-t a j 1. Cable air ovens using the T-t curves from the fire test. ' Underwriters Laboratories (UL) Subject 1724 discusses one_ method for air oven testing. 2. Comparison of the fire test T-t curve to existing cable performance 1 data, such as data from equipment qualification (EQ) testing. EQ t testing is typically performed to rigorous conditions, including rated voltage and current. By correlating the EQ test T-t curve to the fire test T-t a rve, the EQ test data would provide a viable q mechanism to ensure cable functionality. A.large body of EQ test t F data for many cable types exists today. Use of EQ data thus represents a cost-effective approach to address cable functionality for fire testing for those cases where the 325 "F limit is exceeded. I SJAFF RESPONSE The staff agrees with the comment provided th7 comparison of fire test i temperature profiles to existing EQ and LOCA test results considers the temperature-rise due to self heating effects of in-plant power cables. See the staff response to Comment XII.1, (page 28), and Section III of the attachment to the acceptance criteria. j COMMENT 7 - Initial Cable Operatina Temperature j NUMARC repeated its comment on initial cable operating temperature and its effect on the total temperature rise from the NUMARC letter of December 8,~1992 (Section III, (page 10)). \\ STAFF RESPONSE The staff addressed the effects of initial cable operating temperature on cable functionality in'its response to Comment III.6, (page 13). COMMENT 8 - Insulation Resistance Testing "The formula for determining minimum acceptable insulation resistance is taken from IEEE 690-1984, section A.'10.1, and is intended for use with new cables at room temperature. Testing of cables at elevated r temperatures (i.e., immediately following the fire test) to thir criteria represents a more restrictive requirement that the cable has to meet when new. The formula should be adjusted to accommodate the elevated cable temperature at the time of testing." 7 STAFF RESPONSE Except for the last statement, this comment _is ide 'ical to Comment 9 of the NUMARC letter of December 8, 1992. The staff response is provided .i under Comment III.9, (page 14). F XVIII. Florida Power and Light (FPL) letter of August 23, 1993 (Attachment 18) e
t 3 -s-l . i COMMENT 1 Evaluations of Fire Barrier Adecuacy f FPL proposed, in addition to cable functionality testing, that licensees be allowed to perform evaluations, in accordance with Interpretation 4 of i Generic Letter 85-10, of the adequacy of the fire barrier to protect the redundant safe shutdown equipment and camponents (cable) from a design basis fire in a particular plant area. The evaluation would then be retained by the licensee for subsequent NRC audits. STAFF RESPONSE Absent a fire test which demonstrates the fire resistive performance of a r particular cable tray or raceway fire barrier system (refer to GL 86-10, Question 3.2.1, Acceptance Criteria), there is no basis for evaluating i the adequacy of the fire barrier system against a design basis fire by fire modeling plant-specific conditions. With respect to fire barriers used to separate safe shutdown functions within the same fire area, where the performance of the barrier system has been determined by an acceptable test (meeting the acceptance criteria of GL 86-10) and does not meet either the 1-hour or 3-hour fire barrier requirement of Appendix R, then an NRC-approved exemption or deviation is required. The staff did not change its proposed staff position or acceptance criteria in response to this comment. COMMENT 2 - Insulation Resistance Testino i "The proposed supplement discusses cable testing as it relates to engineering analyses that would be performed by the licensee to demonstrate functionality of the protected cable should the cable under test not meet the acceptance criteria under existing regulations. Paragraph C... states in part that " Insulation resistance'(Megger) testing provides. an indication of the cable insulation resistance, whereas the high potential (Hi-Pot) test provides assurance that the 4 cable has sufficient dielectric strength to withstand the applied rated voltage..." "The insulat % resistance test... does not give an indication of the total dielectric strength of the cable insulation. It may also reveal contamination present on the cable in the form of moisture, dirt or carbonization. (Note, that after the proposed te: ting the presence of dirt or other contaminations, particularly on the terminations, caused by testing cabld cause the cable to fail electrical tests leading to an erroneous conclusion that the cable would not have been operable in an actual installation). The applied voltage during insulation resistance testing is generally low (e.g., 500 to 2500 V de depending on the equipment being tested). Therefore, it has historically been a practice to proof-test medium voltage shielded power cable using high-potential testing." "It is FPL's position that of the two tests described, only insulation resistance testing would be applicable to testing the functionality of a 1
=_. y.
- .;E cable that has not met the acceptance criteria after-a test of a fire barrier.
(This assumes that the test setup allows for. proper and safe performance....) High-potential testing, even at reduced voltage levels, would more than likely fail a cable that would have otherwise passed the i test had it been subjected to only operating voltage during the test. Additionally, when examining a fire barrier or the performance of a cable during a test of the fire barrier, it is assumed that the cable will be subject to only the maximum operating voltage." STAFF RESPONSE Insulation reaistance testing is one of the simplest and least potentially dwaging test methods available for assessing cable l functionalfty. It is also the least revealing regarding the state of the insulation condition. The Megger +est is a preliminary " pass-fail" test to confirm gross insulation condition and the absence of short circuits f as a result of fire exposure. -The performance of a pre and post Megger test permits a quick assessment whether cable degradation has occurred during the fire test. The subsequent performance of a successful high-potential test provides a more definitive confirmation of insulation t soundness. These functionality tests as recommendtJ represents only one i approach to justify observed deviations to the fire barrier criteria and they were not intended to substitute for cable qualification tests. The l tests recommended are typical tests conducted for maintenance purposes in l nuclear power plants. Alternate methods to assess d. gradation of cable functionality are permissible under Supplement I to GL 86-10 and will be evaluated by the staff on a case by case basis. l COMMENT L _Hiah-Potential Testina l i "High-potential (both ac and dc) testing is generally used to detect i gross imperfections in the cable insulation, perforations of the 1 insulation, or improper practices / materials used in splicing / terminating the cable. High-potential testing of cables is 'only recommended for shielded power cables (these are generally cables rated E 5000 V); i however, based upon tests currently being performed by EPRI on aged cables, it appears that dc high-potential testing may significantly accelerate aging of the cable such that it may no longer be recommended as a test method." ( "The proposed supplement... state "In addition, AC or DC high-potential (Hi-Pot) tut for power cables greater than 100 volts shall be performed after the post-fire Megger tests to assess the dielectric strength. This l test provides assurance that the able will withstand the applied voltage during and after a fire...." The high-potential test is inappropriate for this purpose as previously stated under Comment 2. In general,- the i thickness of insulation on a power cable is far in excess of that necessary for the normal operating voltage applied to the cable. f Mechanical strength of the insulation (e.g., that necessary to withstand I handling during installation and termination) is the overriding consideration for determining the thickness." - -. I
'l e
- i "For example, based upon Table B1 in AEIC Stds CS6-87 and CSS-87, the minimum average insulation thickness for an 8 kV rated cable, 1000 kemil J
or less would be 115-140 mils for ethylene propylene rubber (EPR),_ thermoplastic, or crosslinked polyethylene (XLPE). Each of these insulating materials has a dielectric strength of at least 400 V/ mil (based upon ASTM Std D 149). Using these numbers, the dielectric, i strength of the cable insulation based solely upon its minimum average thickness would range from 46-to 56-kV. It is this level of insulation that the high-potential test is designed to detect failure in, rather i than whether the cable would withstand its operating voltage (i.e., the' intent of the testing to be conducted under the proposed supplement). l STAFF RESPONSE As noted by FPL, "it has historically been a practice to proof-test i medium voltage shielded power cable using high-potential testing." The purpose of the high-potential (Hi-Pot) test is to verify-or confirm the findings of the Megger test. In the case of medium power cables only, 1 the staff believes that a Me9ger test which is subsequently followed by a Hi-Pot test would both detect any circuit degradation and confirm the current carrying capability of the cable to ensure that a loss of function did not occur due to the fire exposure. The functionality tests recommended represent but one approach to justify observed deviations to the fire barrier criteria and they are not intended to substitute for l cable qualification tests. The tests recommended are also typical tests conducted for maintenance purposes in nuclear power plants. Alternate j methods to assess degradation of cable functionality are permissible J under Supplement I to GL 86-10 which will be evaluated by the staff on a case-by-case basis. COMMENT 4 - Cable Functionality Testina i "The proposed supplement in paragraph c. presents a table of cable type, i operating voltage and tests (including test voltages). The proposed supplement states "The table below summarizes the Megger and Hi-Pot test voltages which, when applied to power, control and instrumentation cables, would constitute an acceptable cable functionality test." i "FPL disagrees with both the table and statement. For the reasons discussed in other comments, high-potential testing of the cables should 1 not be performed. In addition, recommending such tests for non-shielded i power cable (i.e., <1000 V ac) is contrary to all industry standards, I even for newly installed cable. The use of a high-potential test for i cables that have already sustained some damage during the fire barrier i test to evaluate whether or not they would have been functional would be inappropriate." " Additionally, the test voltage for the insulation resistance measurements are too high. For example, the three industry standards that describe this testing for newly installed cable at generating stations and substations are IEEE Std. 422-1986, IEEE Std. 690-1984 and IEEE 525-1992. Each of these standards recommend that insulation
e - -. ~., ' resistance tests for low-voltage power and control cable be at a minimum ) of 500 V dc. Recommendations vary on the need to insulation resistance test instrumentation. For example, IEEE 690-1984, Appendix A, clause j A10.1 (4) states " Insulation resistance measurements should be performed i on instrumentation cables if circuit performance is dependent upon level of insulation resistance. Cable manufacturers' recommendations.should always be considered." If manufacturing standards are considered, both i NEMA Std WC 7-1988 (ICEA S-66-524), and NEMA Std WC 8-1988 t (ICEA S-68-516) recommend a test voltage of 100 to 500 V dc for 1 insulation resistance testing of new cable at the factory." "FPL proposes the following test voltages for insulation resistance f testing for various cables tested (additionally, it is proposed that no j testing be performed during the fire test unless it can be demonstrated i that this testing can be done safely): i i Operating Megger test Cable Tvoe Voltaae Voltaae j Power Cable 21000 V ac 2500 V dc 1000 V ac 1000 V de 600 V ac 500 V dc i 300 V dc 500 V dc i Control Cable s 240 V ac 500 V dc 5 300 V dc 500 V dc Instrumentation
- i Cable 300 V dc i
- If the instrumentation cable's circuit performance is not l
dependent upon the level of insulation resistance, the ANS circuit integrity shall be used as the acceptance criteria." j STAFF RESPONSE The staff disagrees with the comment and the proposed test voltages for insulation resistance testing for various cables. The merits of the proposed cable functionality test are based on the industry accepted practice of performing in situ maintenance insulation resistance tests at i 1000 V dc for 600 V class power cables. The 600 V class cable is insulated for 600 V RMS or a peak voltage value of 852 V (1.42 x 600 V). Further, it should be recognized that the de voltage is not as stressful j as the ac voltage stress. In order to simulate an equivalent level of de voltage stress as the ac voltage would impose on the cable insulation in normal service, the industry standards and manufacturers recommend that de test voltages should be at least 2 to 3 times the nominal j operating voltage. The purpose of these functionality tests is to search out for potential damage in the cable that could prevent it from i performing its function during and after a fire exposure. The test l i
i i i - i i voltage values used for assessing cable functionality have to be. i sufficiently high enough to search out the potential damage in the cable that may have occurred from the fire exposure which is not apparent with lower test voltages. For high voltage power cables (i.e. above 1000v) test voltages used for insulation resistance are not high enough to detect cable degradation. Therefore, a high voltage potential test-is recommended for high voltage power cables. The intent of this test is to establish that the fire explosion did not result in a significant i degradation of the cable insulation. l 1 COMMENT 5 - Test Procedures I "The high temperatures in the vicinity of the fire test chamber requires that the ends on of the cables under test be long enough to enable them-to be in a satisfactory location for electrical testing (i.e., an area cool enough for the test instruments and the test personnel). These longer cable ends may be subjected to mechanical damage,' e.g., as the cable under test is moved about, which may alter test results due'to i damage unrelated to the specific purpose of the test. Additionally the use of test instrument in a high ambient temperature environment will l affect the accuracy of the measurements taken as will the alternate of using long test leads..." t " Ideally, all terminations for the cable under test should be made before l the fire test, however, due to the specific configuration of the test assembly this may not be possible. If the cable terminations are made after the test, this may lead to misleading results. Hovement of the tested cable to enable proper termination can subject it to mechanical i forces that could damage the cable, causing it to fail." l STAFF RESPONSE t The NRC staff addressed the same comments under Comment X.3, (page 26). COMMENT 6 - Secuence of Tests l "In paragraph c, the fourth paragraph discusses the r.eed to 'immediately' Megger test all cables. Performance of the Megger' test takes time, thus adding to the I or 3 hour testing time since the test assembly would remain in the oven at or near test temperature (the ' assembly and cable would see I+ or 3+ hours of elevated temperatures). The additional time, at temperature, could cause a test failure. If high-potential testing as r described in the proposed supplement, is also performed in the ' oven' then the time of temperature exposure of the test assembly would be further increased. If the electrical cable testing is to be performed, j it is more logical to complete the fire test, perform the hose stream i test, then, if necessary, perform any electrical cable testing." i i l
.. 4 C l ) 6 i STAFF RESPONSE With the exception of instrumentation or special application cables where circuit performance is sensitive to changes in insulation resistance, the test sequence recommended by the commenter (fire test, hose stream test, electrical cable testing), is essentially the same as that currently specified in Supplement I to GL 86-10. Recent fire endurance tests-performed by TU Electric for CPSES validated this approach. The bases for the staff position on testing instrumentation or special application cables is provided in the staff response to Comment II.5, (page 8). COMMENT 7 - Proposed Electrical Tests "The proposed electrical tests used to determine functionality if the test cable fails to meet acceptance criteria are new to the industry and should be reviewed for feasibility and personal safety implications. This process should include appropriate industry review (e.g., cable manufactures, IEEE, AEIC, ICEA, etc.).
RESPONSE
The tests specified in Supplement I to GL 86-10 are typical tests conducted for maintenance purposes in nuclear power plants. The tests i are only new as a test methodology to enable applicants to provide engineering justification that observed deviations from the fire barrier acceptance criteria will not impact the functionality of planned cable applications. The staff did not change its proposed staff position or acceptance criteria in response to this comment. XIX. Arizona Public Service Company (APS) letter of August 23, 1993 { (Attachment 19) l COMMENT I - Apolication of Test receptance Criteria APS requested that the supplement state that the acceptance criteria are forward looking and do not result in the need for retesting or analysis of fire barriers previously evaluated and found acceptable by licensees in accordance with GL 86-10, unless they have been formally identified by the NRC as indeterminate. STAFF RESPONSE The staff addressed application of the acceptance criteria in its response to Comment V.7, (page 19). i COMMENT 2 - Acceptance Criteria Conservatism APS stated that conservatism should not be added to standard fire i endurance test acceptance criteria for fire barrier systems that are i traditionally used in industrial applications. When considering the defense-in-depth approach used in the nuclear power fire protection ~ \\ l
l I j program compliance, additional conservatism beyond that already inherent y in fire barrier qualification would have a compounding impact and is not necessary. STAFF RESPONSE l i The staff agrees that conservatism should not be added to standard fire endurance test acceptance criteria for fire barrier systems that are traditionally used in industrial applications. For this reason, the staff, in GL 86-10, specified the acceptance criteria of NFPA 251, j " Standard Methods of Fire Tests of Building Construction and Materials," as being applicable to cable wrap fire barrier systems. This position 10 not changed by Supplement I to GL 86-10. COMMENT 3 - Cable Discoloration APS contends that cable discoloration as a specific example of thermal cable degradation is inappropriate. STAFF RESPONSE The bases for the NRC staff position on cable discoloration are provided l in the staff response to Comment XVI.2, (page 36). j COMMENT 4 - Thermocouple Placemerl APS stated that the overall purpose of the raceway fire protection is 'to ensure functionality of the protected cables during (and after) the fire i exposure, the copper conductor should be routed above the rungs of the cable tray where the cables are routed. r STAFF RESP 0NSE The staff disagrees with the comment. The bases for the thermocouple placement criteria specified in Supplement I to GL 86-10 is provided in i the supplement and under the staff responses to Comments III.4 (page 12), i XII.1 (page 28), XII.3 (page 31), XII.5 (page 31), XIV.2 (page 33), and XVI.1 (page 36) and Comment XVII.3 (page 39). COMMENT 5 - Thermocouples on Cables APS stated that the installation of thermocouples on test specimen cables is not justified and that individual cable temperature measurements j should be optional. 1 ~ i STAFF RESPONSE The staff agrees with this comment and revised Supplement I to GL 86-10 appropriately. t 4 4 l I
I t ! COMMENT 6 - Removal of Compensatory Measurn Section V of the proposed GL discusses-the need for an engineering evaluation to demonstrate functionality in'the event that temperature l limits are exceeded, or visual damage is observed to the cables. This evaluation will require NRC approval. APS stated-that-the forthcoming 1( utility efforts to address installed Thermo-Lag configurations could result in submittal of large numbers of such evaluations, and corresponding delays in the NRC approval cycle. APS believes the process -l for NRC review and approval, as outlined in the proposed supplement to GL 86-10, should allow for the removal of existing utility compensatory-measures following completion if the engineering analysis and any - associated modifications to the barrier system. In addition, APS l recommends that the existing guidance of GL 86-10 provides that utilities could document these types of analyses for subsequent NRC review during inspections. STAFF RESPONSE The purpose of these fire barrier systems is to provide assurance that l the protected safe shutdown function is free of fire damage. Cable i functionality is dependent on the chemical makeup of the cable insulation - and the jacket, and its function. The staff concluded that the placement l of thermocouples as specified in Supplement I to GL 86-10,~ the temperature data obtained from these thermocouples during the test-fire j exposure, and observations of barrier condition following the fire t exposure and hose stream tests,_will provide sufficient data to allow judgements to be made regarding fire barrier performance and the ~! condition of the cables during the fire exposure. Cables installed in these barrier systems that exhibit signs of damage are not free of fire damage and therefore, the fire barrier system did not perform its required fire resistive function. An engineering evaluation which. demonstrates the functionality of fire damaged cables is considered to be L a technical bases for establishing the equivalency in fire ufety of ine tested configuration to the level of fire safety which is provided'by a qualified fire barrier system. The staff considers these conditions to deviate from NRC fire protection requirements and therefore, require NRC j approval. The purpose of the recommended functionality tests is to justify observed deviations in fire barrier performance. Engineering analyses justifying these deviations should not rely substantially upon i the equipment (e.g., cable) qualification as the basis for acceptance. 1 It is the licensees' responsibility to make operability determinations. Therefore, prior to receiving NRC approval, a licensee can declare the barriers operable and remove the compensatory measures. Operability l determinations should be based on the engineering evaluations that j demonstrate that the barriers are operable and that the barrier modifications, if any are needed, have been completed. l l 1 l
v 1 l COMMENT 7 - Confiaurations'to be Tested APS noted that several test specimens will be required to qualify various - l sizes and runs of cable trays and conduits, junctions boxes, etc. The APS position is that the construction techniques and methods should be consistent with the tested configuration. The critical parameters of the i physical characteristics of installation should be the basis for accepting and qualifying various configurations, and not necessarily the exact size of raceway that was fire tested. APS contends that the tests performed by TU and TVA showed the failure mode for a fire barrier configuration larger than an enclosure for a small diameter conduits is j! structural. j Therefore, the use of critical parameters of the physical characteristics of the installation should govern the acceptance, regardless of raceway j size. \\ STAFF RESPONSE 1 Full-scale fire endurance tests observed by the staff indicate that the conditions of fire barrier failure are linked to the size of the raceway and the structural ability of the fire barrier system itself. Small' cable tray and raceway fire barrier systems have the tendency to exceed the thermal performance criterion, while wide cable trays' fail structurally. Therefore, raceway size is a critical test specimen 'l parameter. The staff provided additional information on bounding j configurations in its response to Comment XVI.5, (page 37). i COMMENT 8 - Combustibility it APS recommends that the GL allow fire modeling techniques to determine if l fire barrier materials are combustible in the form which they are used under the conditions anticipated. STAFF RESPONSE I i The NRC staff position on combustibility is provided in its response to l Comment IV.1, (page 15). NRC guidance does not preclude the use of I modeling techniques to assess the impact of materials installed in nuclear power plants under anticipated conditions. j i COMMENT 9 - Initial Cable Operatina Temperature APS agrees that cable normal operating temperature is a consideration in the engineering evaluation. However, initial operating temperature is e only a consideration for power cables, or control and instrument cables l that may be in the same enclosure with power cables. Power cables will not be subjected to rated voltage and current prior to the fire exposure, i and may only be intermittently energized, or not energized at all, prior to the fire exposure. The effect of initial temperature on endpoint i i
i j l i I temperature is not a simple function of adding the difference between the-l initial temperature and ambient air temperature to the measured temperature rise. 1 STAFF RESPONSE The staff addressed the effects of initial cable operating temperature on l cable functionality in its response to Comment III.3, (page 11). [ i COMMENT 10 - Cable Functionality } l APS recommends that the proposed NRC criteria be revised to state that comparison of fire test temperature profiles to existing EQ and LOCA test results, or air oven test results, is an acceptable approach to -l demonstrate cable functionality. j i STAFF RESPONSE I The staff agrees, in part, with the comment. The staff addressed the use i of EQ and LOCA test data in its response to Comment III.7, (page 14). XX. Iowa Electric Light and Power Company letter of August 27, 1993 (Attachment 20) i COMMENT 1 - Support for NUMARC Comments "We support the comments in NUMARC's letter of December 8,1992." I STAFF RESPONSE The staff responded to the NUMARC comments in Section III, (page 10). J COMMENT 2 - Appendix P Deviations "we believe that the staff should provide additional review guidance that specifies the margin of safety or acceptance criteria that is required 3 for determining the adequacy or acceptability of deviations from the requirements of Appendix R, i.e., if the fire barrier will only meet the required acceptance criteria (1) and (3) for a period of time less that i the required 1-or 3-hour barrier ratings. This guidance should specifically address barrier protection in relation to combustible loading and, as an alternative, in terms of its affect on core damage." STAFF RESPONSE I The objective of Supplement I to GL 86-10 is to provide acceptance i criteria for conducting and evaluating fire endurance tests. With the i exception of cable functionality evaluations, guidance for assessing fire barriers that deviate from the requirements of Appendix R is outside the scope of the supplement. j i
~i Absent a fire test which demonstrates the fire resistive performance _of a particular cable tray or raceway fire barrier system (see GL 86-10, Question 3.2.1, " Acceptance Criteria"), there is no valid technical basis for evaluating the performance of the fire barrier against plant-specific ~ conditions or fire hazards. With respect to those fire barriers used to separate safe shutdown functions within the same fire area,_ where the performance of the barrier system has been established by a valid fire endurance test (meeting the acceptance criteria of GL 86-10), but it does not meet either the 1-hour or 3-hour fire resistive requirement of Appendix R, then an exemption or deviation is required. Staff approval of exemptions and deviations requests would be based on technical evaluations that demonstrate that the level of fire safety provided for t the area of concern is equivalent in performance to that required by either the regulations or a plant-specific license condition. XXI. Southern Nuclear Operating Company letter of August 23, 1993 i (Attachment 21) COMMENT 1 - Fire Barrier Evaluations "We recommend the following changes to the acceptance criteria: ... For those barriers which are not capable of performing its intended function, a deviation based on demonstrating that " ' functionality of i thermally degraded cable was maintained and that these cables would have l adequately performed its intended function during and after a postulated fire exposure may be granted..." to read "... For those barriers which are not capable of performing its 1 intended function, an engineering evaluation which demonstrates that the functionality of the thermally degraded cables was maintained and that i these cables would have adequately performed its intended function during i and after a postulated fire exposure shall be performed by the licensee and maintained for inspection with the plant records for review... i STAFF RESPONSE H The staff disagrees with the comment. The staff addressed evaluations of in-plant fire barriers and the need for NRC approval of deviations and exemptions in its responses to Comment III.2 (page 10), Comment XVIII.1 (page 42), and Comment XX.2, (page 52). COMMENT 2 - Hose Stream Test "the basis for the requirement for hose stream testing... appears to be applicable more to the testing of penetration seals and fire zone barriers rather than on hour or three hour cable tray wrap. Since the intetyity of the barrier is not required to protect the cable from the effects of a fire hose stream, and the barrier has already served its i
n. 4 ? I ! delaying function at a time when a hose stream might.be applied in l combatting the fire, it is recommended that the criteria for cable wrap fire barrier testing be revised to delete references to hose stream testing." j STAFF RESPONSE I The staff disagrees with the comment. Hose stream testing is important f because fire fighting activities could cause limited structural [ challenges to the fire barrier itself. The rational. for performing the hose stream test at the end of the fire exposure is that if a barrier can e withstand the forces imposed by the hose stream at the fire exposure end-point, then it would be structurally resistant to fire fighting activities at any time before the fire exposure end point. l I The bases for the NRC staff position on hose stream testing are provided i in the staff response to Comment I.1, page 1. The staff did not change its proposed staff position or acceptance criteria in response to the l comment. XXII. Georgia Power Company letter of August 23, 1993 (Attachment 22) The comments submitted by Georgia Power Company were the same as those submitted by Southern Nuclear Operating Company (Section XXI, (page 52)). t XXIII. Darchem Engineering, Ltd letter of September 13, 1993 (Attachment 23) l COMMENT 1 - Hose Stream Test Methods ) Darchem restated its comments on hose stream testing from its letter of i February 2~, 1993. (See Section VII, (page 20).) l STAFF RESPONSE i The bases for the NRC staff position on hose stream testing are provided in the staff response to Comment I.1, page 1. COMMENT 2 - Combustibility "The language used to identify ASTM E-136 as a method for determination of combustibility merely indicates the possible use of this test method ~rather than proscribing its use. Again, the reference to ASTM D-3286 or NFPA 259 merely suggests its potential use as one means of determining heat release of the fire protection materials. Put alongside the mandatory requirements of ASTM D1929 and ASTM E84, it would appear not only that the specific combustibility and heat release tests referenced, but also the test categories themselves, are not mandatory. We would suggest a change to indicate a requirement for such testing, referencing ASTM E136 and ASTM D3286 or NFPA 259, or equivalents [ as necessary requirements."
e s i }. STAFF RESPONSE The test methods and criteria specified in Supplement 1 to GL 86-10 are ) guidance, not NRC requirements. The staff considers the guidance as a approach for demonstrating compliance with NRC fire protection requirements. Supplement I to GL 86-10 recommends ASTM E136 as a test method for demonstrating if a material is combustible. Licensees ~may use this test method or propose alternatives to the staff which they consider i equivalent. COMMENT 3 - Toxicity l "We also request consideration of maximum allowable levels of toxic substances such as cyanide, CFCs, etc." l STAFF RESPONSE Nuclear power plants contain numerous materials that can burn and, therefore, release combustion products (e.g., cable insulations, charcoal filters, plastics, paper, wood, lube and transformer oils). The staff j recognizes that all combustion products are toxic to varying degrees. i In-plant fire brigades are trained and equipped to fight fires in the hazardous environments created during fires and to control and mitigate . smoke during fire fighting. However, existing NRC requirements do not place limits on the toxicity of the combustion products of in-plant i materials. The establishment of such limits is outside the scope of i Supplement I to GL 86-10, which is intended to refine and clarify existing NRC staff guidance and acceptance criteria for fire endurance j tests. Moreover, any toxicity criteria would have to be applied to all in-plant materials since, in this regard, there is nothing unique about i fire barriers. ~l t XXIV. Alleger letter of April 16, 1993 i COMMENT 1 - Hose Stream Test Methods i/l "you claim the fog gives you more water 375 gallons verses the solid j stream 210 gallons. What a misconception-The old " Industry Standard" ANI i 1979 called for 2% minutes of solid stream and 2% minutes of fog - solid stream being preferred. This is 187.5 gallons for fog and 525 gallons of water (solid stream) for virtually all tests as a safety margin" -l STAFF RESPONSE Each of the hose stream test methods specified in Supplement I to GL 86-10 is based on nozzle type and size, orifice pressure, distance ~! from the test specimen during the test, and duration of apr rication. The supplement does not specify that a specific quantity of v4ter of water be delivered and water quantity is not the basis for the base stream test i options accepted by the staff. The bases for the NRC staff position on j hose stream testing are provided in the staff respmise to Comment 1.1, page 1. i t l
i i - j XXV. Alleger letter of June 24, 1993 } COMMENT 1 - Cold Side Temperature Criterion j "the reason the NRC proposed fire endurance criteria is that the Industry l used primarily the ANI bulletin #5(79) and the ANI criteria allowed the internal temperature of the envelope to exceed 325 F required by the NRC l on the cold side of the system. The NRC requirement now is determined to l be on the cold side of the barrier ASTM E-Il9, yet prior to 1992 there was no definition of this as you allowed and accepted the ANI "Not to - t Exceed 325 F on the cables inside the envelope." Now your staff is. ) changing the cold side to the tray side similar to ANI." I STAFF RESPONSE j In GL 86-10 of April 24, 1986, the staff reaffirmed that its acceptance criteria for raceway fire barriers was based on NFPA 251, " Standard Methods of Fire Tests of Building Construction and Materials." A fundamental NFPA criterion, and therefore, a staff criterion, for i qualifying a fire barrier is that the unexposed side temperature of the fire barrier did not rise more than 139 'C [250 'F] above the ambient j temperature at the start of the fire endurance test. (The end point r temperature limit is commonly referred to as 163 *C [325 'F), based on l initial ambient air temperature of 24 *C [75 'F].) This criterion is not changed by Supplement I to GL 86-10. 3 The staff'did not change its proposed staff position or acceptance criteria in response to this comment. COMMENT 2 "You state 'the ANI method does not require the barrier to remain intact during the fire and hose stream test' Yet the ANI bulletin you reference i to specifically states acceptance criteria to ASTM E-119 which your proposed definition states the barrier remains intact and does not allow projection of water beyond the unexposed surface." l STAFF RESPONSE - Barrier Condition Followino the Test The staff reviewed ANI Bulletin 5(79) and found that it does not I reference NFPA 251 and that its only reference to ASTM E-119 is "the protective envelope shall be exposed to the standard temperature-time-curve found in ASTM E-119-76." ANI Bulletin 5(79) does not appear to i invoke or rely on any other part of ASTM E-119, including-the ASTM E-119 acceptance criteria. The staff also found that ANI Bulletin 5(79) does I not require that the fire barrier remain intact during the fire and hose i stream tests. The staff criteria of Supplement I to GL 86-10 does i specify that the fire barrier remain intact during the fire and hose stream tests. The staff did not change its proposed staff position or acceptance criteria in response to this comment. w w
i o^ i COMMENT 3 - Cable Deoradation "ANI allowed the degradation of the cables yet the ANI required the same 325 F maximum temperature on the cables every foot.. It would seem to me that the criteria assumed that any maintaining of the 325 F "wouldn't i degrade the cables." STAFF RESPONSE' The ' staff reviewed ANI Bulletin 5(79) and did 'not find an' acceptance. I criterion based on cable temperatures. It appears that ANI did allow: cable degradation since the ANI acceptance criteria is based on maintaining cable circuit integrity at low voltage. The staff did not change its proposed staff-position or acceptance criteria in response to this comment. XXVI. Alleger letter of June 25, 1993 COMMENT 1 - Cable Temperature Versus Fire Barrier Temperature l "the difference is ANI measured temperature on the cables not the barrier material, your staff proposes to now measure on the external surface of the raceway. ANI's method which has been used by all manufactures for years measures the temperature the cables will actually see-you want to a measure the raceway. This change appears that it has been done wrong in the past but your making it appear that the raceway verses the past is a great deal better-not so. If cable on a curve touches the barrier' material the cable could be much hotter that the raceway if those cables ~ are 16 gcuge polyethylene and could fail before the raceway temperature reaches it's maximum." STAFF RESPONSE The staff agrees that cables in intimate contact with the unexposed side of a fire barrier are most vulnerable to damage during a fire. To minimize this vulnerability, while maintaining previously established temperature rise criteria, the acceptance criteria is based on the. i temperatures of the unexposed side of the fire barrier material itself. The intent of protecting cables within a fire barrier system is to minimize the maximum temperature the cables will experience. Under the conditions of acceptance specified in Supplement I to GL 86-10, the thermal performance of a fire barrier is judged by measuring temperature on the unexposed side of the fire barrier material itself. If the average temperature of the unexposed side of the fire barrier is maintained below the limit established by the criteria (139 *C [250 *F] above the initial temperatures at the start of the test) the cables. within the fire barrier system will be exposed to temperatures _less than that of the unexposed fire barrier. surface. If the acceptance criteria was based on measuring the temperatures of the cables instead of the 1 unexposed side of the fire barrier, the likelihood of thermally damaging cables in contact with the fire barrier material is greatly increased.
i. <: The staff did not change its proposed staff position or acceptance criteria in response to this comment. COMMENT 2 - Hose Stream Test Damaae "What you neglect to say in your proposed criteria is that the previous criteria always had "no passage of water through the barrier" which obviously would ensure against the "no visible signs of conductor or raceway." STAFF RESPONSE The staff agrees that the acceptance criteria of GL 86-10 in the area of hose stream testing is the same as that specified in Supplement I to GL 86-10. The performance criterion of "no visible signs of conductor or raceway" was added to clarify p vious GL 86-10 acceptance criteria. COMMENT 3 - Combustibility "the product was supposed to have a non-combustible feature as the others have. ANI... required non-combustible-you found the product to have the combustibility of " treated pine boards" you now say there isn't a requirement for non-combustible they only need to include in the " combustible loading factor" STAFF RESPONSE The NRC staff position on combustibility of fire barriers is provided in the staff response to Comment IV.1, (page 15). The staff reviewed ANI Bulleti.i 5(79) and found that it specifies that fire barriers should be non-combustible. ANI gave an example of noncombustible as having a flame spread of 25 or less. It is the staff opinion that flame spread is only one property of combustibility. [ Filename: G:\\GL8610PC\\PUBLIC2.COM]
F Table 1 Page 1 COMPARISON OF NRC PROPOSED FIRE ENDURANCE TESTING CRITERIA TO GL 86-10 CRITERIA i NRC PROPOSED CRITERIA GL 86-10 CRITERIA RATIONALE FOR CHANGE Temperature, as Temperature, as Temperature - Difficult measured on the measured on the to measure a uniform external surface of the unexposed side of the temperature on the fire i Raceway, should not fire barrier material, barrier material exceed 163 "C [325 "F] should not exceed surface. Raceway temps i (Note 1). 163 *C [325 'F]. provide good indication of internal temp-rise j This temperature is and potential barrier determined by averaging failure locations temperature readings of during the test. I similar series of l thermocouple (e.g., cable tray side rail). 1 (Note 2) i Barrier Condition - Barrier condition - The Barrier Condition - Raceway fire barrier barrier shall have Cotton waste has not shall remain intact. No withstood the fire and been used in raceway visible signs of hose stream test fire barrier , ting as a conductor or raceway without the passage of an indicator of barrier J after fire and hose flame or hot gasses hot failure. Visual j stream test. enough to ignite cotton inspection process waste. provides a better indication of barrier 1 condition after the fire and hose stream test. Hose Stream testing is Hose Stream testing is Hose Stream - To i required. (solid stream required. (solid stream reflect alternative i test as required by test as required by methods found NFPA 251 on second test NFPA 251) acceptable (Note 3). specimen after being The use of a fog nozzle subjected to a fire for the hose stream at exposure of 1/2 the end of a full duration (Note 4) or a duration of the fire fog stream after the test provides a good full fire exposure.) method for testing erosion and cooling effects. i
i Table 1 Page 2 NRC PROPOSED CRITERIA GL 86-10 CRITERIA RATIONALE FOR CHANGE Cable condition - When Cable condition - No cable condition - The cables are included in consideration given to objective of these fire l the test specimen, determining the barriers is to assure their condition must be material condition of that thermal damage to visually inspected. the cable. protected safe shutdown Cables when inspected cables or components should show no signs of does not occur. degraded conditions resulting from the thermal affects of de fire exposure. GUIDANCE FOR ENGINEERING EVALUATIONS JUSTIFYING DEVIATIONS FROM THE FIRE BARRIER ACCEPTANCE CRITERIA + Functionality is needed Functionality - No Functionality is to be demonstrated if guidance provided. Up considered to be a any of the preceding to licensees to deviation from the criteria are exceeded demonstrate by acceptance criteria and (Note 5). engineering analysis. must be justified on a l Analysis kept on file case-by-case basis Methods when cables are for NRC review. which includes an excluded from test Engineering analysis assessment of cable specimen: generally based on jacket material. l internal temperature Comparison of internal below the ignition temp. profiles to EQ temperature. No and LOCA test data consideration given cable operating Air oven test of cables temperatures within the at rated voltage with barrier at the onset of megger and Hi-Pot tests the fire exposure. (Note 6) Method when cables are in test specimen include megger and Hi-Pot testing (Note 7) Demonstration of functionality shall also consider operating temperature of the cables inside the fire barrier at the onset of the fire exposure. i Note 1 - The 163 *C [325 *F] temperature condition was established by allowing the internal temperature on the raceway surface to rise a maximum of 139 *C [250 *F] above the initial temperature of the test specimen (assumed to be 24 *C [75 *F]).
Table 1 Page 3 Note 2 - NFPA 251/ASTil-E119 allows the temperature condition to be determined by averaging the thermocouple readings. The conditions of acceptance are also placed on the temperature conditions measured by a single thermocouple. Under these conditions of acceptance, if any single thermocouple exceeds 30 percent above the maximum allowable temperature rise (i.e., max. allowable 139 *C + 42 *C = 181 *C [250 *F + 75 *F = 325 *F]) the test is considered to have exceeded the criteria temperature limit. Note 3 - SRP 9.5.1 recognizes the use of a fog stream as an alternative hose stream testing method for qualifying fire barrier penetration seals. Note 4 - The application of this hose stream test method provides assurance that the cable tray or raceway fire barrier system has sufficient structural integrity to resist minor fire related barrier breaches caused by falling objects. Note 5 - A fire barrier system which does not meet the performance conditions of the fire endurance acceptance criteria is considered not to be a rated fire barrier. For those performance conditions (i.e., high raceway temperature, barrier openings, water projection, cable damage) which deviate from this acceptance criteria, an engineering analysis which clearly demonstrates the functionality of the protected component (s) or cable (s) can be submitted to the staff for review. The purpose of the recommended functionality tests is to justify observed deviations in fire barrier performance. Engineering analyses justifying these deviations should not rely substantially upon the equipment (e.g., cable) qualification as the basis for acceptance (Staff).) These deviations will be evaluated by the staff on a case-by-case basis. Note 6 - For fire barrier systems tested without cables, plant-specific cable types will be subjected to an air oven test when the fire barrier temperature rise criterion is exceeded. These cables will be exposed to a temperature profile as determined by the internal raceway thermocouples during the fire test. Cables will be tested at rated voltage. Megger and Hi-Pot testing will be performed in a consistent manner to those tests performed for cables included in a fire barrier test specimen and subjected to the fire endurance test. Note 7 - Megger testing of cables included in the fire test specimen will be performed before, during (instrumentation cables only) and immediately after the fire exposure and subjecting power cables which have voltage ratings 1 1000 volts ac to a Hi-Pot test (60%) immediately after the fire exposure.
i ' Table 2 Page 1 COMPARISON OF NRC PROPOSED FIRE ENDURANCE TESTING CRITERIA TO THE ASTM (PROPOSED) AND UL STANDARDS NRC PROPOSED CRITERIA ASTM PROPOSED CRITERIA UL1724 CRITERIA Temperature, as Temperature, as Temperature - No measured on the measured on the temperature criterion. external surface of the external surface of the Internal fire barrier Raceway, should not raceway, should not temperature profile exceed 163 *C [325 *F] exceed 163 *C [325 "F]. developed from fire (Note 1). test data. Profile used to test cables in an air oven. This temperature is Same method of data determined by averaging averaging as temperature readings of recommended by the NRC similar series of proposed criteria. thermocouple (e.g., cable tray side rail). (Note'2) Thermocouple Placement Thermocouple Placement Thermocouple Placement CABLE TRAYS (test CABLE TRAYS (test CABLE TRAYS (test specimens without specimens without specimens without t cables) - Tcs every 6-cables) - Same as NRC cables) - Basically the inches on the cable proposed criteria. same as the NRC tray side rails and a proposed criteria. bare No. 8AWG stranded copper conductor installed on the top of the cable rungs down the center of the cable i tray. I CABLE TRAYS (with CABLE TRAYS (with CABLE TRAYS (with cables) - Tcs every 6-cables) - Criteria does cables) - Criteria does inches on the cable not recommend including not recommend including tray side rails and No. cables in the test cables in the test 8 AWG bare stranded specimen. specimen. copper conductor installed on the bottom of the tray rungs in close contact with the fire barrier material. Second bare copper conductor with Tcs every 6-inches is installed on top of cables. i
4 Table 2 Page 2 NRC PROPOSED CRITERIA AsfM PROPOSED CRITERIA UL1724 CRITERIA Barrier Condition - Barrier Condition - Barrier Condition - Raceway fire barrier Raceway fire barrier Raceway fire barrier-shall remain intact. No shall remain intact. No shall remain intact. No visible signs of visible signs of visible signs of l conductor or raceway raceway after fire and raceway after fire and I after fire and hose hose stream test. hose stream test. j stream test. Hose Stream testing is Hose Stream - No hose Hose Stream - Solid performed. stream testing. stream is required to be applied to the fire (solid stream test as test specimen after required by NFPA 251 on being subjected to the second test specimen full fire exposure, after being subjected to a fire exposure of 1/2 duration or a fog stream (Note 3) after the full fire exposure.) Cable condition - If Cable condition - No Cable condition - No cables are included in consideration given to consideration is given the test specimen, the determining the to determining the cable condition must be material condition of material condition of i visually inspected. the cable since, cables the cables since, l Cables, when inspected, are not included in the cables are not included i should show no signs of test specimen. in the test specimen. degraded conditions resulting from the l thermal effects of the fire exposure. J
n w . Table 2 Page 3 i NRC PROPOSED CRITERIA ASTM PROPOSED CRITERIA ULI724 CRITERIA - t Functionality is needed Functionality - No Functionality - to be demonstrated if guidance provided. Compressive load air any of the preceding oven test on cables at criteria are exceeded rated voltage. (Note 4). Consideration for cable Methods when cables are operating temperatures. excluded from test j specimen: 1. Comparison of internal temp. profiles to EQ and LOCA test data. 3 2. Air oven test of cables at rated voltage with megger and Hi-Pot tests. l (Note 5) { Method when cables are in test specimen include megger and Hi-Pot testing. (Note 6) Note 1 - The 163 *C [325 *F] temperature condition was established by allowing the unexposed temperature of the fire barrier surface to rise a maximum of 139 *C [250 *F] above the ambient internal test specimen air temperature, assumed to be 24 *C [75 *F], during the fire test. i Note 2 - NFPA 251/ ASTM-E119 allows the temperature condition to be determined by averaging the thermocouple readings. The conditions of acceptance are also placed on the temperature conditions measured by a single thermocouple. Under these conditions of acceptance, if any single thermocouple exceeds 30 percent above the maximum allowable temperature rise (i.e., max. allowable 139 *C + 42 *C = 181 *C [250 *F + 75 *F = 325 *F]) the test is considered to have exceeded the criteria temperature limit. Note 3 - SRP 9.5.1 recognizes the use of a fog stream as an alternative hose stream testing method for qualifying fire barrier penetration seals. Note 4 - A fire barrier system which does not meet the performance conditions of the fire endurance acceptance criteria is considered not to be a rated fire barrier. For those performance conditions (i.e., high raceway temperature, barrier openings, water projection, cable damage) which deviate from this acceptance criteria, an engineering analysis which clearly demonstrates the functionality of the protected component (s) or cable (s) can be submitted to i the staff for review. The purpose of the recommended functionality tests is
^ ~ Table 2 Page 4 t to justify observed deviations in fire barrier performance. Engineering analyses justifying these deviations should not rely substantially upon the equipment (e.g., cable) qualification as the basis for acceptance (Staff).) These deviations will be evaluated by the staff on a case-by-case basis. Note 5 - For fire barrier systems tested without cables, plant-specific cable types will be subjected to an air oven test when the fire barrier temperature rise criterion is exceeded. These cables will be exposed to a temperature profile as determined by the internal raceway thermocouples during the fire test. Cables will be tested at rated voltage. Megger and Hi-Pot testing will be performed in a consistent manner to those tests performed for cables included in a fire barrier test specimen and subjected to the fire endurance test. Note 6 - Megger testing of cables included in the fire test specimen will be performed before, during (instrumentation cables only) and immediately after the fire exposure and subjecting power cables which have voltage ratings 2 1000 volts ac to a Hi-Pot test (60%) immediately after the fire exposure. 1 I t i .\\ 4 i l 4 l I
Table 3 Psge 1 COMPARISON OF NRC PROPOSED FIRE ENDURANCE TESTING CRITERIA TO TU, TVA, AND NUMARC CRITERIA l NRC NUMARC TU TVA THERMAL THERMAL THERMAL THERMAL PERFORMANCE PERFORMANCE PERFORMANCE PERFORMANCE i Raceway temps. Raceway temps. Raceway temps Raceway temps. below 250 F rise below 250 F rise below 250 F rise below 250 F rise Preferred method Cables used in Plant specific No cables in no cables in test cable tray test cables used in raceway during specimen. specimens. test specimen. fire test. (see Note 1) J Thermocouple Thermocouple Thermocouple Thermocouple P1acement P1acement P1acement P1acement CONDUITS - Tcs CONDUITS - Tcs CONDUITS - Tcs CONDUITS - Tcs 1 every 6-inches on every 6-inches on every 12-incnes every 6-inches j exterior surface. exterior surface. on exterior on exterior l Internal conduit Internal conduit surface. Tcs surface. temperatures temperatures every 6-inches Internal conduit determined by No. determinad by along selected temperatures 8 AWG bare copper bare copper cables in determined by conductor conductor conduit. No. 8 AWG bare j instrumented with instrumented with copper conductor Tcs every Tcs every instrumented 6-inches. 6-inches-. with Tcs every 6-inches. CABLE TRAYS - CABLE TRAYS - Tcs CABLE TRAYS - Tcs CABLE TRAYS - No (with cables) Tes every 6-inches on every 12-inches cable trays every 6-inches on the cable tray along tray side tested. i the cable tray side rails. Bare rails. Tcs every side rails. Bare copper conductor 6-inches on power copper conductor installed on the cable down center installed on the top of the cable of tray, and on a bottom of the rungs doun the instrument cable tray rungs in center of the and a control close contact cable tray. 15 % cabl e. The with the fire cable fill instrument and barrier material. installed in the control cable Second bare tray with the were located on copper conductor copper conductor. either side of with Tcs Second copper the power cable installed on top conductor with midway between of cables. TCs installed on the tray side top of cables. rail and the center power cable. =
Table 3 Page 2 NRC NUMARC TU TVA CABLE CONDITION CABLE CONDITION CABLE CONDITION CABLE CONDITION f Visual inspection Exceeds 250 F Exceeds 250*F Exceeds 250 F of cables temperature rise temperature rise temperature i required. Damage criterion, visual criterion, visual rise criterion, to the cables inspection of the inspection of the functional + indicate barrier cables required. cables required. testing q failure. Damage to the Damage to the required. cables indicate cables indicate barrier failure, barrier failure. HOSE STREAM TEST HOSE STREAM TEST HOSE STREAM TEST HOSE STREAM TEST l Hose stream Fog stream at the Fog stream at the Fog stream at testing required end of the fire end of the fire the end of the (See note 2) test. test. fire test. I 1 ( i f i ? P
l m ,( Table 3 Page 3 l NRC
- dMARC TU TVA FUNCTIONALITY TEST A FUNCTIONALITY FUNCTIONALITY FUNCTIONALITY TEST TEST TEST Is needed to be None For Compressive demonstrated if any of temperatures load air oven the preceding criteria exceeding test on i
are exceeded (Note 3). 250 F rise, cables at with cable rated Methods when cables are damage. voltage. excluded from test specimen: Megger testing Megger - Room temp. 1. Comparison of - in water internal temp. Hi-pot testing i profiles to EQ and Hi-Pot on LOCA test data medium voltage power 2. Air oven test of cables. cables at rated 1 voltage with megger Consideratior, and Hi-Pot tests for cable (Note 4) operating temperatures. Method when cables are in test specimen include megger and Hi-Pot testing (Note 5) Demonstration of i functionality shall also 5 consider operating I temperature of the cables inside the fire barrier at the onset of the fire exposure. Note 1 - In order to assure generic applicability of the test results to various cable insulation types, the preferred method for testing a raceway i fire barrier in the staff's proposed criteria is without cables. The proposed j staff criteria, for cable trays tested without cables, recommends thermocouples be placed every 6-inches on the cable tray side rails and a No. ] 8 AWG bare stranded copper conductor which is installed on the top of the cable rungs and down the center of the cable tray. Note 2 - The NRC proposed criteria allows the use of either the solid hose stream test as recommended by ASTM E-Il9, UL 1724, and NFPA 251 or the use of a fog hose stream. The basis for allowing the fog hose stream test as an alternate is established in SRP 9.5.1, Position 5.e, Electrical Cable Construction, Cable Trays, and Cable Penetrations. Under this Position, the use of a fog hose stream test is considered to be an acceptable hose stream test method for fire barrier penetration seals.
.3x - o: - Table 3 Page 4 Note 3 - A fire barrier system which does not meet the ?erformance conditions of the fire endurance acceptance criteria is considered not to be a rated fire barrier. For those performance conditions (i.e., high raceway temperature, barrier openings, water projection, cable damage) which deviate from this acceptance criteria, an engineering analysis which clearly demonstrates the functionality of the protected component (s) or cable (s) can be submitted to the staff for review. The purpose of the recommended functionality tests is to justify observed deviations in fire barrier performance. Engineering analyses justifying these deviations should not rely substantially upon the equipment (e.g., cable) qualification as the basis for acceptance. These deviations will be evaluated by the staff on a case-by-case basis. Note 4 - For fire barrier systems tested without cables, plant-specific cable types will be subjected to an air oven test when the fire barrier temperature rise criterion is exceeded. These cables will be exposed to a temperature profile as determined by the internal raceway thermocouples during the fire test. Cables will be tested at rated voltage. Megger and Hi-Pot testing will be performed in a consistent manner to those tests performed for cables-included in a fire barrier test specimen and subjected to the fire endurance test. Note 5 - Megger testing of cables included in the fire test specimen will be performed before, during (instrumentation cables only) and immediately after the fire exposure and subjecting power cables which have voltage ratings > 1000 volts ac to a Hi-Pot test (60%) immediately after the fire exposure. -i i ? 1 1 J}}