ML20116P246
| ML20116P246 | |
| Person / Time | |
|---|---|
| Issue date: | 07/31/1996 |
| From: | Chris Bajwa, Khadijah West Office of Nuclear Reactor Regulation |
| To: | |
| References | |
| NUREG-1552, NUDOCS 9608230207 | |
| Download: ML20116P246 (55) | |
Text
!
i NUREG-1552 i
i
! Fire Barrier Penetration Seals l in Nuclear Power Plants I
i k
i I
i i
U.S. Nuclear Regulatory Commission l
Office of Nuclear Reactor Regulation C. S. Bajwa, K. S. West i
REgg l
8 i
l 5
l l
\\,***! /
i 9608230207 960731 y
$$$2 I
/ 0 t' PDR d o\\\\
AVAILABILITY NOTICE Availability of Reference Materials Cited in NRC Publications Most documents cited in NRC publications will be available from one of the following sources:
1.
The NRC Public Document Room 2120 L Street, NW., Lower Level, Washington, DC 20555-0001 2.
The Superintendent of Documents, U.S. Government Printing Office, P. O. Box 37082, Washington, DC 20402-9328
'3.
The National Technical Information Service, Springfield, VA 22161-0002 Although the listing that follows represents the majority of documents cited in NRC publics-tions, it is not intended to be exhaustive.
Referenced documents available for inspection and copying for a fee from the NRC Public Document Room include NRC correspondence and internal NRC memoranda; NRC bulletins, circulars, information notices, inspection and investigation notices; licensee event reports; vendor reports and correspondence; Commission papers; and applicant and licensee docu-ments and correspondence.
The following documents in the NUREG series are available for purchase from the Government Printing Office: formal NRC staff and contractor reports, NRC-sponsored conference pro-ceedings, international agreement reports, grantee reports, and NRC booklets and bro-chures. Also available are regulatory guides, NRC regulations in the Code of Federal Regula-tions, and Nuclear Regulatory Commission Issuances.
Documents available from the National Technical Information Service include NUREG-series reports and technical reports prepared by other Federal agencies and reports prepared by th9 Atomic Energy Commission, forerunner agency to the Nuclear Regulatory Commission.
Documents available from public and special technical libraries include all open literature items, such as books, joumal articles, and transactions. Federal Register notices, Federal and State legislation, and congressional reports can usually be obtained from these libraries.
Documents such as theses, dissertations, foreign reports and translations, and non-NRC con-ference proceedings are available for purchase from the organization sponsoring the publica-tion cited.
Single copies of NRC draft reports are available free, to the extent of supply, upon written request to the Office of Administration, Distribution and Mail Services Section, U.S. Nuclear Regulatory Commission, Washington DC 20555-0001.
Copies of industry ccdes and standards used in a substantive manner in the NRC regulatory process are maintained at the NRC Library, Two White Flint North,11545 Rockville Pike, Rock-ville, MD 20852-2738, for use by the public. Codes and standards are usually copyrighted and may be purchased from the originating organization or, if they are American National Standards, from the American National Standards Institute,1430 Broadway, New York, NY 10018-3308.
l NUREG-1552 l
l Fire Barrier Penetration Seals l
in Nuclear Power Plants i
Manuscript Completed: June 1996 Date Published: July 1996 j
i C. S. Bajwa, K. S. West l
Division of Systems Safety and Analysis Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555-0001
,# ~%.,,
1
\\...../
l
ABSTRACT As part of fire protection defense in depth, nuclear power specific problems of safety significance or concerns uith plants are divided into separate fire areas by tire-rated generic implications. The stalTconcluded that the structural barriers. l' ire-rated penetration seals are general condition of penetration seal programs in installed to seal certain openings in these barriers. The industry is satisfactory. The statT also concluded that seals maintain the fire-resistive integrity of the barriers actions it had taken in 1988 and 1994 to address and provide reasonable assurance that a lire will be potential penetration seal problems increased industry contined to the area in which it started. The sta! Tor the an areness of such problems and resulted in more Ilire Protection Engineering Section, Ollice of Nuclear thorough sun eillances, maintenance, and corrective Reactor Regulation,Il.S. Nuclear Regulatory actions. lhese previous staff actions, together with Conunission, conducted a comprehensive technical continued licensee upkeep of existing penetration seal assessment of penetration seals to address reports of programs and continued NRC inspections, are adequate potential problems, to detennine if there were any to maintain public health and safety. The stalT problems of safety significance, and to determine if NRC reconunended several minor revisions to the NRC fire requirements, review guidance, and inspection protection regulation and review guidance.
procedures are adequate. 'the stalTdid not find plant-
)
iii NUREG-1552 I
f TABLE OF CONTENTS Ens AllSlRACT Sn EXECUTIVE
SUMMARY
. vii 1
DISCUSSION 1
1.1 Defense in Depth and the Role of Penetration Seals.
I 1.2 Background.
2 1.3 Fire Protection Program Reassessment 3
1.4 AEOD Penetration Seal Review 3
2 FIRE BARRJER PENETRATION SEAL MATERIALS 3
2.1 Population and Types of Seals 3
2.2 Silicone Foams 4
2.3 Silicone Elastomers.
4 2.4 Silicone Gels 4
2.5 Other Sealants 5
2.6 Damming Materials.
5 3
QUALIFICATION TESTS OF PENETRATION SEALS 5
3.1 Test Metimds and Acceptance Criteria.
5 3.2 Fire Testing Laboratories 6
4 FIRE PROTECTION REGULATIONS, GUIDANCE. AND INSPECTION PROCEDURES
.7 4.1 llackground
.7 4.2 Regulations 8
4.2.1 GDC 3 and 10 CFR 50.48 8
4.2.2 Appendix R to 10 CFR Part 50 8
4.3 Review Guidance 8
4.3.1 Appendix A to ilTP APCSil 9.5-1 9
4.3.2 Standard Review Plan (NUREG-0800) 9 4.3.3 Generic Letter 86-10 9
4.4 Inspection Procedures.
10 5
TECIINICAL ASSESSMENT 10 5.1 Review of Penetration Seal Part 21 Reports 10 5.2 Review of Reactor Operating Experience 11 5.2.1 Review of Licensee Event Reports 11 5.2.2 Review of Reactor Fire Experience.
I1 5.3 Review of Previous NRC Inspection Results 12 5.4 Review of Plant-Specific Corrective Action Programs.
12 5.4.1 Wolf Creek Generating Station 13 5.4.2 Virgil C. Summer Nuclear Station 13 5.4.3 Vermont Yankee Nuclear Power Station 14 l
5.4.4 Diablo Canyon Nuclear Power Plant 14 l
5.5 Focused Audits ar.d Inspections of Nuclear Plants 14 l
5.5.1 Davis-Besse Nuclear Power Station 15 5.5.2 Waterford 3 Nuclear Power Plant 15 5.5.3 Susquehanna Steam Electric Station.
15 l
5.5.4 Calven ClitTs Nuclear Power Plant.
15 v
~ _ -.
Contents 4
l'i!Es 5.5.5 Washington Nuclear Project 2..
15 5.5.6 Watts liar Nuclear Power Plant.
16 l
5.6 Vendor Inspections.
16 5.6.1 Dow Corning Corporation.
16 5.6.2 13 rand Fire Protection Services, incorporated.
16 5.6.3 Il&ll Progressive Materials and Technologies, Incorporated
. 17 5.7 Installation, Surveillance, Maintenance, and Repair 17 5.8 Combustibility of Silicone-Based Seal Materials 18 5.9 Dow Corning Corporation Silicone Foam Fonnulation Change 19 i
5.10 Aging and Shrinkage 19 5.11 Silicone-Ilased Material Curing 20 l
5.12 Comparison of Tested to As-lluilt Configurations 20
)
5.12.1 Size of Scaled Opening
. 21 5.12.2 Penetrating items.
. 21 5.12.3 Cable Type and Fill.
. 2l 5.12.4 Danuning Materials
. 22 5.12.5 Configuration Orientation
. 22 5.12.6 Material Type and 'lhickness.
. 22 5.12.7 Type Testing
. 22 5.13 Comparison of Thermo-Lag Fire 11arriers to Penetration Seals
. 22 6
SUMMARY
OF FINDINGS.
. 23 7
CONCI.USIONS
. 24 8
RECOMMENDATIONS.
24 9
13113LIOGRAPIIY
. 24 Appendix A Summaries of NRC Generic Communications Regarding Penetration Seals Appendix 11 Action Plan Summary, Technical Assessment of Fire 13arrier Penetration Seals Appendix C Comparison of Industry Fire Endurance Test Standards Appendix D Acronyms and Abbreviations Appendix E SECY-96-146: Technical Assessment of Fire llarrier Penetration Seals in Nuclear Power Plants NUREG-1552 vi
EXECUTIVE
SUMMARY
As part of fire protection defense in depth, nuclear pow er and previous NRC inspection and assessment results; and plants are divided into separate fire areas by fire-rated assessed the data and infonnation obtained from the field walls and fire-rated floor-ceiling assemblies. These fire work and document reviews.
barriers offer icasonable assurance that a fire will not spread from one plant area to another. Openings in these The stalT found several minor w eaknesses with some of fire barriers, w hich are know n as penetrations, allow the plant-specilie penetration seal programs that it such items as cables, conduits, cable trays, pipes, and review ed. Ilowever, these weaknesses did not result in j
ducts to pass from one fire area to another. Fire barrier problems with the penetration seals installed in the i
penetration seals are installed to seal these openings and plants. On the basis of the totality of the infonnation it maintain the fire-resistive integrity of the fire barriers.
found and assessed, including the " Report on the t
i Penetration seals are not technically complex, nor are Reassessment of the NRC Fire Protection Program" that they unique to the nuclear industry. In fact, they are had been conducted by NRR, the review of fir.: barrier universally accepted building components that are used penetration seals that had been conducted by the Office in a variety of residential, conunercial, and industrial for Analy sis and Evaluation of Operational Data buildings u herever fire-resistive separation is needed.
(AEOD), repe ns that had been prepared by Sandia lhe same penetration seal materials, fire test standards, National Laboramries on the population of fire barrier
[
and installation techniques that are used by the nuclear types installed in nuclear power plants and penetration industry are used in these other industries. A large body seal aging, and the other documents referenced in this j
of fire test results (nuclear and non-nuclear) and fire report, the stalT concluded that the general condition of experience (non-nuclear) has proven the fire-resistive penetration seal programs in industry is satisfactory,1he capabilities and elTeetiveness of penetration seals.
stalT did not find plant-specific problems of safety significance or concerns with generic implications.
In about 1985, the staff had become aware of the possibility that some licensees may not have been Even though the staff found the condition of penetration complying uith UX Nuclear Regulatory Commission seal programs in industry to be satisfactory, it expects (NRC) requirements and guidance for fire barrier that minor plant-specilie deficiencies nill occasionally penetration scak in response to these concerns, in 1987 be found during future licensee surveillances and NRC and 1988, the NRC staff had assessed aspects of fire inspections. Ilow ever, potential fire barrier penetration barrier penetration seats. The staff had reviewed such seal problems are understood; industry consensus fire relevant data as licensee event reports, inspection test standards are available and are follow ed; and fire tert findings, and fire test reports; intetriew ed industry staff; results and qualified fire-resistant seal materials and inspected licensees and vendors; and reviewed a sample designs are available. Therefore, licensees have the population of as-built fire barrier penetration seal means to correct problems, and staff oversight will installations and the substantiating documentation.
continue to ensure corrections on a case by-case basis.
Although it did not find widespread problems or safety-Fire protection defense in depth pros ides reasonable significant generie issues, the stalT addressed potential assurance that such deliciencies uill not present an pmblems in a series ofinfonnation notices.
undue risk to public health and safety. Finally, the staff concluded that the actions it had taken in 1988 and 1994 Since 1992, potential problems have again been to address potential penetration seal problems increased reported. In response, the Office of Nuclear Reactor industry an areness of such problems and resulted in Regulation (NRR) conducted a second technical more thorough smveillances, maintenance, and assessment of fire barrier penetration seak The principal corrective actions. These actions, together with purposes of the second assessment, w hich is documented continued licensee upkeep of existing penetration seal here, were to address potential problems, to detennine if programs and continued NRC inspections, are adequate there were any problems of safety significance or with to maintain public health and safety.
generic implications. and to determine if NRC regulatory requirements, res iew guidance, and inspection On the basis of the technical assessment documented procedures for penetration seals are adequate. In support here, the staff recommends the following: (1) revise the of this assessment, the staff conducted inspections at NRL lire protection guidance documents to reflect the reactor and vendor facilities; witnessed fire endurance current National Fire Protection Association position on tests of penetration seals; reviewed operatinF experience testing laboratories (Section 3.2),(2) delete the vii NUREG-1552
Executive Sununary noncombustibility criterion for seal materials from the The stalTof the Fire Protection Engineering Section NRC fire protection regulation and review guidance made presentations on fire barrier penetration seals and (Section 5 8); (3) develop guidance for comparing fire-this assessment at the International Conference on Fire tested penetration seal configurations to as-built Protection and Prevention in Nuclear Facilities, configurations (Section 5.12); and (4) make this liarcelona, Spain (December 5 through 7,1994); the assessment report available to the general public and Nuclear Energy Institute Fire Protection Forum, St.
industry (Section 7).
Petersburg, Florida (January 29,1996); and NRC Regulatory Information Conferences (May 1994 and
%c Fire Protection Engineering Section of NRR April 1996). On March 7,1996, the stafTof the Fire conducted the technical assessment documented here.
Protection Engineering Section presented the results of The Special Inspection 13 ranch of NRR and Ilrookhaven this technical asxssment to the Advisory Conunittee or National Laboratory helped w ith the reactor and vendor Reactor Safeguards, Fire Protection Subcommittee.
inspections. StafTof NRR, AEOD, the Office of Nuclear Material Safety and Safeguards (NMSS), Reg;on I, In addition, the stalTinformed the Commission of the Region 11, Region 111, and Region IV conducted a peer findings of this report in SECY-96-146, " Technical review of this assessment report. An Independent Assessment of Fire Barrier Penetration Seals in Nuclear Management Review Panel chaired by NRR and Power Plants," dated July 1,1996. That paper is represented by NMSS and the Office of Nuclear appended to the text.
Regulatory Research conducted a final review of this report.
NUREG-1552 viii
u 1 DISCUSSION important because they are the first and last lines of defense against a fire. That is, during the early stages of a fire, the barriers confine the fire and protect important I.1 Defense in Depth and the Role equipment until the fire detection and automatic fire of Penetration Seals
""PP'*"i "SFStem4 Perate. In addition, in the unlikely event that an automatic lire protection system fails to operate, the structural barriers continue to provide Nuclear power plants licensed to operate by the U.S,.
passive f.tre protection.
Nuclear Regulatory Conum.ssion (NRC) use the defense-in-depth concept of echelons of fire protection features Penetrations are openings in structural fire barriers that to ach.ieve a high degree of f. ire safety. The obj.ect.ive of.
allow such services as piping and instrument tubing; del.ense m depth.is to (1) prevent f. ires from starting; conduits, cables, and cable trays; and heating, (2) detect rapidly, control, and exttnguish promptly those ventilation, and a.tt conditionmg ducts to pass from one i.tres that do occur; and (3) provide protection I.or fire area to another. Penetrations may also be left em structures, systems, and components.urportant to saf.ety for futs whion To m'W5 h & mis-so that a fire that is not prompth extinguished will not mtegnty of the fire barriers, f. ire-rated penetration seals prevent the safe shutdow n of the plant. The multiple are in. stalled in the penetrations and in the gaps and layers of fire protect. ion provided by the defense-in-depth annular spaces around the penetrating items.2 The seals concept provide reasonalde assurance that weaknesses or are one element of fire protection defense in depth and, deficiencies m any echelon will not present an undue nsk like the structural fire barriers in u hich they are installed, to public health and safety. To achieve defense m depth, are passive t. ire protect. ion features. Iheir des.ign function each operating reactor has an NRC-approved i.tre g, g g g,.. 4;g ;,
g protectmn program.' The licensees have designed the itre protect important equipment within the area from a fire protection programs by analyses that (1) considered outside the area.
potential fire hazards, (2) detennined the effects of fires in the plant on the ability to safely shut down the reactor Fire barrier penetration seals are not technically or on the ability to unnum/c and control the release of complex, nor are they unique to the nuclear industry. In radioactivity to the environment, and (3) specified fact, they are universally accepted building components measures for fire prevention, lire continement, tire that are used in residential, commercial, and industrial detectmn, automatic and manual tire suppression, and buildings wherever fire-resistive separction is needed.'
post-itre safe-shutdou n capability. To conime a fire and the same penetration seal materials, fire test standards, limit fire damage, licensees divile nuclear power plant and installation techniques that are used by the nuclear buildmgs into separate file areas. ihese are generally industry are used in these other industries [ A large body rooms or plant areas that have fire-rated walls and fire-of k U b d h pui
@nden rated floor-ceding assembhes. These fire-rated w alls and spanning decades, has proven the lire-resistive floor-ceiling assembhes (stmetural fire barriers) have capailitid effectiveness of penetration seals. (As an sufficient fire resistance to withstand the fire hazards example, in the 1995 edition ofits Fire Resistance located in the fire area and, u necessary, to protect Directory,' Underw riters Laboratories, Incorporated unportant equipment within the area from a fire outside (UL), listed more than 800 penetration seal designs that the area. Most nuclear power plant fire barriers are of substantial reinforced-concrete construction and have a fire-resistance rating of 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> (see Section 3). This passive fire protection concept, w hich is called Tire doors and fire-rated duct dampers are also used
" compartmentation," is a fundamental fire safety to close fire barrier penetrations. These 11re protection measure. It is not unique to nuclear power plants. The features are not addressed here.
fire barriers, which accomplish their intended design function simply by being in place during a fire, are
'Outside the nuclear industry, penetrations are sometimes called " poke-throughs," penetration seals are commonly called "firestops," and sealing fire barrier
'When properly designed, implemented, and maintained, a fire protection program satisfies
' Architects, engineers, building code officials, and Section 50.48, " Fire protection," of Title 10 of the Code others use the Fire Resistance Directory to identify fire-offederalRegulations, Part 50.
tested penetration seal designs.
Discussion it had tested and approved.) It is generally accepted readily. In this instance, a more detailed fire hazards among fire protection engineers, building code officials, analysis is needed to assess the effects of the fire spread.
and other professionals responsible for building design The stalT, in Generic Letter 86-10," Implementation of and fire safety, that properly designed, tested, installed, Fire Protection Requirements," April 24,1986, provided inspected, and maintained penetration seals provide guidance for evaluating fire area boundaries (see reasonable assurance that the fire-resistive integrity of Section 433).
the fire barriers in w hich they are installed will be maintained.
1.2 Background
The etTectiveness of structural fire barriers is largely In about 1985, the staff had become aw-of the dependent on their inherent fire resistance, details of pmibility that some licensees mr not have been constructmn, and protectmn of penetrations. Some tire complyiEg with NRC requirements and guidance for fire baniers (both structural barriers and penetration seals) barrier penetration seals. In response to these potential are more important to I,tre protection delense m depth problems,in 1987 and 1988, the NRC staff had assessed than others. The importance of specific fire barners aspects of fire barrier penetration sealt The staff had depends on many factors, such as the importance of the review ed such relevant data as licensee event reports, equipment in the fire area (and adjacent areas); the inspection findings, and fire test repons; interview ed conhguration and location of combustible materials and industry staff; inspected licensees and vendors; and other tire hazards, if any, m the areas; the potential for revie d a um# popimion of Ailt b hain tire grow th in the areas; the other fire protection features penetration sealinstallations and the substantiating mstalled in the areas; and the accessibility of the areas t documentation. In parallel with these efforts, the staff the plant fire bngade. The importance of specific bd fonned an NRC roundtable group to assess w hat it penetration seals depends on these factors and on such had found and to detennine whether or not regulatory factors as thetr stie, their location or position m the fire g;gy,,
g barrier, and the number and si/es of the other seals in the barrier.
The staff did not find uidespread problems or safety-significant issues. Following its assessment, the staff in order of overall importance to tire protection defense imed a series of information notices.' Information in depth structural lire barriers are generally more Notice (IN) 88-04, " Inadequate Qualification and important than fire banier penetration seals Qualified 1)o umentation of Fire Banier Penetration Seals,"
fire protection engineers determme the signtheance of February 5,1988, addressed what the staff had found individual tire barriers by fire hazards analyses.
during its assessment and summarized existing staff Although a detailed discussion of such analyses is guidance related to lire barrier penetration seals. It did beyond the scope of this report, the following discussion not address or identify plant-specific problems.
illustrates tlus pomt.
IN 88-56," Potential Problems With Silicone foam Fire Harrier Penetration Seals," August 4,1988, informed 1
If a structural fire barrier fails and collapses under fire licensees that nonconfonning conditions such as splits, exposure, the adjacent fire area can become involved in gaps, voids, and lack of fill might exist in silicone foam the lire in a short period of time. (Because of the penetration sealt IN 88-04 Supplement 1," Inadequate substantial construction of nuclear pow er plant ! ire Qualification and Documentation of Fire Barrier barriers and fire protection defense in depth, the staff Penetration Seals," August 9,1988, addressed several does not consider this a credible fire scenario.) Failure pid-spee fic cases of misapplication of silicone foam of a penetration sealis generally not as sigmlicant a lire inaterials. (Later, the statf issued IN 94-28, " Potential threat as a failure of a structural tire barrier. In most Problems With Fire Harrier Penetration Seals," April 5, cases, a seal failure would initially create a localized hot 1994, to infonn licensees of potential problems that spot in the adjacent fire area in the area of the seal. If there are no combustible materials in the adjacent fire area in the vicinity of the failed seal (for example, if the
%& li ce mimiud a progm for reviewing penetration seal is for a pipe), smoke and hot gases will information notices and detennining whether or not the move into the adjacent area, but the spread of fire into nfonnation is applicable to its facilities. The staff the area will be limited. Conversely, if there are reviewed these programs during NRC inspections.
combustible materials in the vicinity of the failed seal Therefore, the staff decided that information notices (for example, if the penetration seal is for a loaded cable w ere an appropriate vehicle for disseminating what it 1
tray), the fire could spread into the adjacent area more teamed during its assessment.
NUREG.1552 2
Discussion could go undetected as a result ofinadequate 1.4 AEOD Penetration Seal Review surveillance inspection procedures and inadequate acceptance criteria.) Appendix A is a summary of NRC The Ollice for Analysis and Evaluation of Operational generie communications related to lire banier Data (AEOD) had performed a review of fire barrier penetration seals.
penetration seals u hich it documented in a memorandum of May 23,1995, from C.E. Rossi, AEOD, to Since 1992, new potential problems with penetration G.M. Ilolahan, NRR. It had included reviews of the Dow seals have been reported. In response, the Fire Protection Corning Part 21 silicone cure issue (see Section 5.1) and Engineering Section of the Office of Nuclear Reactor of engoing NRR activities relating to the tecimical Regulation (NRR) conducted a second technical assessment documented here. AEOD had reached many assessment of fire barrier penetration seals. The principal of the same conclusions about penetration seals that purposes of the second assessment, w hich is documented NRR had found. AEOD did, however, raise questions in this report, w ere to address potential problems, to about NRC procedures for inspecting penetration seals detennine if there were any widespread problems of (see Section 4.4) and aging of silicone seals (see safety significance or with generie implications, and to Section 5.10).
detennine if NRC requirements, review guidance, and inspection procedures for penetration seals are adequate.
2 FIRE BARRIER The stafT audited the fire barrier penetration seal programs at two nuclear power plants, inspected the fire PENETRATION SEAL barrier penetration seal programs at four nuclear plants, MATERIALS inspected the manufacturer and suppher of the most widely used seal materials, and inspected two contractors that installed penetration seals. The staf f also witnessed 2.1 Population and Types of Seals fire endurance tests of penetration seals, reviewed operating experience and previous NRC inspection Most of the fire barrier penetration seals installed in results, assessed the data and information obtained from nuclear pow er plants are designed to achieve a fire-the document reviews and field w ork, sought out any resistance rating of 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br />. Penetration seals with fire-conunonality or correlation of evidence that may suggest resistance ratings of I hour and 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> are also used.
additional tecimical problems or trends; and detennined Seals are generally classified as either mechanical w hether or not there are generic problems of safety penetration seals or electrical penetration seals significance. Appendix B is a summary of the staff depending on the seu penetrants, e.g., piping or cable action plan fcr the technical assessment documented trays, respectively. The results of a survey of 32 nuclear here.
power units conducted by Sandia National Laboratories (SNL) and reported in a letter report of May 29,1992, 1.3 Fire Protection Program entitled "A Determination of the Population of Fire Barrier Types in Generating Stations," is sununarized in Reassessment Table 1. The objective of the survey was to identify the fire barrier materials installed in nuclear power plants.
In 1993, the staff of NRR had completed a reassessment lhe survey revealed that silicone-based materials are the of the reactor tire protection program. NRR had predominant penetration seal materials. The survey also doemnented that reassessment in " Report on the revealed that the average number of penetration seals per Reassessment of the NRC Fire Protection Program,"
nuclear power plant unit is about 3000 and a single unit Febmary 27,1993. The staff had concluded that can have up to 10,000 seak The selection of materials licensees were complying with regulatory requirements for a particular penetration real depends on a number of and that there were no major or recurring issues with factors, including the fire resistance needed, the type of penetration seals. The report had recommended that the penetrants, the envirorunent, and the need for the seal to etaff confinn the adequacy of the NRC review and serve multiple functions (e.g., radiation protection, inspection programs to address fire barrier elements, pressure 1,oundary, and flood protection).
including fire barrier penetration seals. Ilowever,it made no recommendations regarding penetration seal operability.
j 3
Seal Materials Table i Representative Population of SealTypes Seal Material Average Range of Installations Installations per per Unit Unit w
l Silicone foam 1668 0 - 3700 Silicone elastomer 820 0 - 8500 Mineral w ool 436 0 2000 Cement (mortar and grout) 424 0 - 3502 Mechanical 33 0 250 2.2 Silicone Foams reported that the average number of clastomer penetration seals per nuclear power plant unit exceeds The silicone foam most widely used in nuclear power 800 The silicone clastomers most widely used in nuclear plants is manufactured and supplied by Dow Corning power plants are manufactured and supplied by Dow Corporation (product infonnation available from Dow Corning Corporation. As with silicone foam, vendors Corning, Midland, M1). Silicone foam is also add proprietary ingredients to the elastomer material to manufactured by General Electric and others.1he increase density or add various capabilities to the s endors that install fire barrier penetration seals purchase elastomer, such as radiation protection properties.
silicone foam from the manufacturers, add proprietary ingredients, and resell the material under proprietary Like silicone foam seals, elastomer seals are formed in trade names. For example, ingredients can be added for place from two components which are mixed in a 1:1 radiation protection, to increase the density of the ratio, by weight or volume, either manually or by a materials, or to change the cure rate.
special mixing apparatus at the point of application. lhe mixed components form a dense, finn, rubber-like Silicone foam seals are fonned in place.1he fonnulation material that cures in from 10 minutes to 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />, has tw o components which are mixed in a 1:1 ratio, by depending on the fonnula of the elastomer and weight or volume, by a special mixing apparatus that conditions at the place ofinstallation. Unlike siliconc j
combines the two parts at the point of application. For foam, silicone elastomers do not expand appreciably i
small applications, special applicator kits are available w hen curing. Generally, because of the higher density, that allow the two parts to be mixed shortly before structural strength, and thennal stability of silicone application. lhe chemical reaction that occurs after the elastomer materials, less thickness is needed in a silicone two components are mixed causes the foam to rise or elastomer seal than in a silicone foam seal, to achieve a expand in volume. Because the silicone foam material similar fire rating.
expands as it cures, a tight-fitting seal fonny in the i
penetration opening. The continued transition of the seal 2.4 Silicone Gels material from the liquid to the solid state is referred to as
" curing " Silicone foam cures in 2 to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
Another silicone product used in penetration seal Shrinkage of the foam materialis nonnal within 24 to 48 applications is silicone gels. Gels display characteristics hours after it is injected in the penetration. Gaps created of both liquids and solids, and they have a specific by shrinkage are filled with adhesive / sealant (see gravity similar to that of water. With added fillers, the Section 2.5).
silicone gel is also an effective fire / radiation barrier. The get material is usually held together in field apphcations 2.3 Silicone Elastomers by a flexible boot. Gel is.,uppded to vendors as a two-component clear material that is mixed together, usually After silicone foam, the most common seal materials are in a 1:1 ratio. Gel seals are used to allow significant low-density silicone clastomers (LDSEs) and high-Penetrant movement and are less widely used than the density silicone elastomers (IIDSEs). Some vendors also silicone foam and silicone clastomers.
supply medium density silicone clastomers. SNL NUREG-1552 4
l Seal Materials l
l 2.5 Other Scalants 3
QUALIFICATION TESTS OF PENETRATION SEALS A silicone adhesive product, umally supplied in caulking gun tubes, is used to repair visibL hrinkage in foam 3.1
,fest Methods and Acceptance seals, seal op mings that are too small for an injection of other tirestop mw rials, and flexible boot seal Criteria
)
l applications.
To gain reasonable assurance that a fire barrier I
in addition to silicone-based materials, fire-rated penetration seal wiii have the required fire-resistance penetration seals are also made of cement materials capability or fire rating (1,2, or 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br />), a (grouts and mortars) ami such fire-retardant materials as representative penetration seal test assembly is subjected l
Flanunastic. In most cases, these materials are installed to a qualification fire endurance test. (Fire tests are also after packing the penetrations with fire-resistant conducted for research purposes and for product materials such as mineral wool (e g., Knowool).
development.) The test methods involve the furnac,-;is e exposure of a full-scale fire barrier penetration seal test Mechanical penetration seals are also used. Such seals specimen. The test specimens are representative of the are typically incorporated in concrete walls during construction for which a fire-resistance rating is desired, construction or are retrofitted by drilling out wall as to materials, workmanship, and such details as the i
material and casting a seal housing in place. They dimensions of parts. The heat input to the test furnace is perfonn their sealing function by mechanically controlled so that the average temperature in the fumace I
compressing a resilient, fire-resistant synthetic material follows as closely as possible the time-temperature curve l
arotmd the penetratmg item-spec fied in the test standard. In the United States, the standards used to test and rate penetration seals specify l
2.6 Damming Materials the standard time-temperature curve defined in Ameri$:an l
Society for Testing and Materials (ASTM) E-119, Damming materials are used to close the cross-sectional
" Standard Test Methods for Fire Tests of fluilding areas of barrier penetrations that are to be sealed.
Construction and Materials." This time-temperature Damming materials, which may be either permanent or curve, which is generally accepted for evaluating and temporary, are used to contain the seal material until it rating the fire resistance of all types of building fire has cured or hardened. Permanent damming materials, barriers, is considered to represent a severe fire which are left in place as integral parts of the penetration exposure. Ilowever, the fire endurance tests are not seal assembly, are fire resistant and have low thennat intended to model any specific room fire or the conductivity and, therefore, contribute to the overall fire-conditions under which the seals will be exposed during resistance rating of the seal assembly. In general, the r: fire, but rather provide a specific standard fire exposure damming materials are left in place if they were part of against which similar fire-rated assemblies can be evaluated.
l the fire-tested penetration seal assembly (see l
Section 3.1). ixample.1 of pennanent damming materials include ceramic fiber (alumina-silica). ceramic liber The test standards and the NRC regulations and guidance blankets (e g., Johns-Manville Corp 2 ration Cerafiber),
documents specify fire test acceptance criteria that l
ceramic fiberboard, and calcium silicate board involve the measured reaponse of the test specimen at the 1
(e g., Johns-Manville Corporation Marinite board).
tin:e into the standard fire exposure that corresponds to Temporary damming materials include particle board, the desired barrier rating. In most cases, the test plywood, duct tape, and rigid foams. Ecsc materials are specimen is also exposed to a hose stream test after the removed after the seal has cured.
fire exposure. For example, a fire barrier penettreion seal design is said to has e a fire-resistance rating of 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> if the tested specimen meets the specified acceptance criteria during at least 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> of the standard fire exposure and the hose stream test. In this example, the fire-resistance rating qualifies the seal design for use as a 3-hour fire-rated barrier.
The aff has accepted the following industry standards for qualifying penetiation seals: (1) ASTM E-119; (2) Nationa! Fire Protection Association (NFPA) 251,
(
Qualification Tests
" Standard Methods of fire Tests of fluilding contractors, test laboratories, research organi/ations, Construction and Materials";(3) ASTM E-814, licensees, and others. The staff observed fire endurance
" Standard Method of Fire Tests oflhrough-Penetration tests of fire barrier penetration seals and reviewed fire Fire Stops"; and (4) Institute of Electrical and test reports during licensing review s and inspections. On Electronics Engineers (IEFE) 634, " Standard Cable the Lsis of these ey ewitness accounts and reviews, the Penetration Fire Stop Qualification fest." In addition, staff has concluded that fire endurance tests have estab-UL tests and approves penetration seals in accordance lished the fire-resistive capabilities of the penetration with American National Standards Institute /UL 1479, seat materials, designs, and configurations installed in
" Fire Tests oflhrough-Penetration Firestops," and other nuclear power plants.
organizations, such as American Nuclear Insurers (ANI) and Factory Mutual (FM), also have test methods and 3.2 Fire Testing Laboratories standards for conducting penetration seal fire endurance tests. The statT has also accepted the installation of During this assessment, the staff did not find technical penetration seals that had been qualified in accordance issues or problems regarding fire testing laboratories.
w ith these test standards.
Ilow ever, there has been confusion about NRC regulatory requirements and review guidance regarding There are variations betw een the test standards and the such laboratories. It has been suggested, for example, test acceptance criteria.1herefore, assessments of fire that fire endurance tests that are not perfonned by a test results consider both the test standard that. as used nationally recogni/cd testing laboratory cannot meet and the acceptance criteria that apply. In general, the NRC fire protection regulatory requirements.-
acceptance critena ensure that the penetration seal does not burn through during the fire cNposure, remains in NRC fire protection regulations' do not cover either fire place during the fire and hose stream exposure, prevents endurance testing or fire test laboratories. NRC fire the passage of flames or gases hot enough to ignite protection guidance documents address these topies in a combustibles that may be on the nonfire side of the test limited fashion. For example, they define " fire barrier" as specimen, and limits the transmittal of heat through the
" components of construction...that are rated by seal and any penetrating items (as determined by approving laboratories." 1 hey also define " approved" as measuring the temperature rise on the oonfire side of the
" tested and accepted for a spehilie purpose or application seal and any penetrating items). Section 4 gives the by a nationally recognized testing laboratory."
acceptance criteria that are specified in the NRC
~
regulations and guidance documents. Appendix C The mission of the National Fire Protection Association, provides a summary and comparison of the fire barrier w hich w as organized in 1896, is to safeguard people, penetration seal fire endurance test standards that have property, and the environment from fire using scientific been endorsed or accepted by the statT, and engineering techniques and education. More than 225 NFPA committees, w hich are represented by 1he ability of a particular penetration seal design t affected interests, develop and publish standards achieve a specific fire rating is configuration dependent.
intended to minimize the possibility and effects of fires.
The ty pe and thickness of the penetration seal material is NFPA is the principal source of fire protection standards a significant factor. Moisture content; material density; and codes in the United States. When the staff developed presence or absence of filler materials or damming its fire protection guidance documents in the 1970s, it materials; cross-sectional area and free area of seal adopted a large number of NFPA standards by reference material; number, type, and arrangement of penetrants; in its guidance documents. At that time, the stafT adopted seal orientation (hori/ontal or vertical); and construction the tenn " nationally recognized testing laboratory" from methods also influence the fire-resistance rating. Specific design considerations for penetration seals are discussed l
in Section 5.12 of this report.
1 i
Decades of experience with the test standards by the
'The NRC fire protection regulations are contained in i
nuclesr and general building industries have provided General Design f'riterion 3,10 CFR 50.48, and adequate assurance that they are appropriate for Appendix R to 10 CFR Part 50. NRC fire protection qualifying fire barrier penetration seals. Ilundreds of review guidance is contained in various branch technical qualification-ty pe fire endurance tests of a wide variety positions and the Standard Review Plan (NUREG-0800).
of penetration seal designs and materials have been The regulations r.nd guidance are discussed at length in performed by material manufacturers, installation Section 4.
Qualification Tests NFPA. Neither NFPA nor NRC defined the term?
also pmvide guidance for the conduct and Consequently, there has been recurring confusion Aout documentation of fire endurance tests.
what constituted a nationally recognized testing laboratory. In the 15th edition of the Fire Protection
'lhe term " nationally recogniecd testing laboratory" is Handbook,1981, NFPA stated that it had dropped the undefined and obsolete. In addition, national prominence term ".ationally recognized testing laooratory" from is not needed to conduct valid fire endurance tests.
documents it published because there was alw ays a doubt Finally, satisfactory ways of selecting suitable test about the definition of a nationally recognized testing facilities are available within the fire protection laboratory, 'lhe staff did not update its guidance engineering community. Therefore, the staff documents to reflect this NFPA position.
recommends that the NRC fire protection guidance documents be revised to reflect the current NFPA 1here is no regulatory requirement that fire tests be position.
conducted by a nationally recognized testing laboratory, e
llistorically, during licensing reviews, the stafT had 4
FIRE PROTECTION accepted the use of fire barriers without reviewing the fire test results if the barriers w cre tested and approved REGULATIONS, GUIDANCE, by UL or FM. Such barriers included fire doors, fire AND INSPECTION walls, and penetration seals. As discussed in Section 4, PROCEDURES the guidance documents present approaches that are acceptable to the staff for meeting regulatory requirements. Ilow ever, liecusees can use approaches 4.I BHCkgr0Und that dilTer from those specified in the guidance document. Therefore, the stafT had also accepted barriers NRC requirements and guidelines for penetration seals that were tested by organizations other than UL and FM.
are contained in a number of documents. The extent to In such cases, the stalImay have reviewed the fire test which these requirements or guidelines are applicable to results."
a specific plant depends on the age of the plant and the commitments established by the licensee in developing NRC does not certify or accredit testing laboratories and its fire protection plan. Some of the potential problems hwat issued guidance for evaluating or assessing the that were raised about penetration seals reflected a poor acceptability of fire testing laboratories to perform fire Frasp of NRC fire protection regulations and guidance tests. In the 17th edition of the Fire Pmtection and the regulatory process. For example, Appendis R, Handbook,1991, NFPA stated that there are many
" Fire Protection Program for Nuclear Power Facilities laboratories in the United States capable of performing Operating Prior to January 1,1979," to Title 10 of the fire-related research and fire testing.1hese include Code ofFederalRegulations (10 CFR) Part 50, was private and industrial laboratories, university thought to be a generically applicable set of laboratories, and government laboratories. NFPA requirements; staff review guidance had been mistaken indicated that evaluations oflaboratories should be based for regulatory requirements, and the flexibility afforded on criteria that generally focus on their overall operation, by guidance documents had not been recognized.
including organization and technical direction, ethical and professional business practices, and the quality In 1971, the Atomic Energy Commission (AEC) control system used by the laboratory. Other more promulgated General Design Criterion (GDC) 3, " Fire specific criteria focus on the persormel, equipment, protection." GDC 3 states,in part," structures, systems, facility, procedures, and recordkeeping for performing and components important to safety shall be designed and reporting test results. The industry fire test standards and located to minimize, consistent with other safety requirements, the probability and effect of fires and explosions. Noncombustible and heat-resistant materials
'At that time,it appeared that UL and FM, two shall be used w herever practical throughout the unit, organizations with historical preeminence in the fire particularly in such locations as the contaimnent and testing field, were generally considered to be nationally control room." 1he AEC did not issue guidelines for secogniicd testing laboratories, implementing GDC 3.
'The staff review of the Watts Bar Nuclear Power On March 22,1975, the Brow ns Ferry Nuclear Power Plant fire protection program was a recent example of Plant had the worst fire ever to occur in a commercial this (see Sections 5.5.6 and 5.6.3).
nuclear power plant operating in the United States. Tuo 7
Regulations, Guidance, and Inspection Procedures reconunendations made by the Special Review Group result of its continuing review of fire protection matters, that investigated the 13 row ns Ferry fire penained to to retroactively apply the requirements for fire protection assurance that the fire protection programs at operating of safe-shutdow n capability, emergency lighting, and nuclear pow er plants conform to GDC 3. The first reactor coolant pump oil collection systems to all plants recommendation was that NRC should develop specific operating prior to January 1,1979, even if the sta!T had guidance for implementing GDC 3. The second was that previously approved an alternative approach. The the NRC should review the fire protection program at remaining sections were backfit to plants only to the each operating plant comparing it to the guidance extent needed to resolve the contested issues, the developed per the first recommendation.
Conunission having decided that the features previously approved by the staff provided an equivalent level of in response to the first recommendation, the staff safety to that provided under these specific provisions of i
developed 13 ranch Technical Position (BTP) Auxiliary Appendix R.
Power Conversion Systems Branch (APCSB) 9.5-1,
" Guidelines for Fire Protection for Nuclear Power Section Ill.M, " Fire barrier cable penetration seal Plants " May 1,1976; and its appendix, " Guidelines for qualification " of Appendix R resolved the disputed issue Fire Protecticn for Nuclear Power Plants Docketed Prior of fire barrier penetration seals and is, therefore, of to July 1,1976," Appendix A, February 24,1977. In interest here. It applied to 13 nuclear power plants.
response to the second recommendation, each operating plant compared its fire protection program to either the Section Hl.M states that penetration seal designs shall guidelines of BTP APCSB 9.5-1 or to the guidelines of utili/c only noncombustible material (see Section 5.8)
Appendix A to BTP APCSB 9.5-1 and the staf f reviewed and shall be qualified by tests that are comparable to the fire protection programs for compliance with the tests used to rate fire barriers. Section Ill.M contains the guidance. Most licensees complied with most of the following acceptance criteria:
implementing guidance. Ilowever, the stafIand some licensees disagreed on 17 issues. To resolve the (1)
Cable fire barrier penetration seal has withstood j
contested issues, on May 29,1980, the NRC proposed the fire endurance test without passage of flame or 10 CFR 50.48, " Fire protection," and Appendix R. " Fire ignition of cables on the unexposed side.
Protection Program for Nuclear Pow er Facilities Operating Prior to January 1,1979," to 10 CFR Part 50 (2)
Temperatures recorded on the unexposed side are (45 FR 36082). The NRC published in the Federal analyzed and the maximum temperature is Register (45 FR 76602) the final fire protection rule sufficiently below the ignition temperatore of the (10 CFR 50.48) and Appendix R to 10 CFR Part 50 on cable insulation temperature.
November 19,1980.
(3)
The fire barrier penetration seal remains intact and 4.2 Regulations d eS " ' "11 * " P' J"cti " r water beyond the unexposed surface during the hose stream test.
4.2.1 GDC 3 and 10 CFR 50.48 4.3 Rev.iew Gu. dance i
The basic fire protection regulation for nuclear power plants is Section 50.48 of 10 CFR Pan 50. It requires, ia The staff did not backlit Appendix R to plants licensed part, that each operating nuclear power plant have a fire to operate after January 1,1979. For these plants, the protection plan that satisfies GDC 3. It references staff reviewed the fire protection programs during Appendix R to 10 CFR Part 50 and several NRC fire licensing against the licensecs' commitments. Most protection guidance documents. GDC 3 and licensees for plants licensed to operate after 10 CFR 50.48 do not explicitly address penetration seals.
January 1,1979 committed to meet the combination of the guidance of Appendix A to BTP APCSB 9.5-1 and the criteria of cedain sectims of Appendix R. In such 4.2.2 Appendix R to 10 CFR Part 50 cases, the sections of Appendix R that the licensee mmnutted to meet apply to the plant as licensing When the staff proposed Appendix R, it intended that the wmmitments, but not as regulatory regmrements. The requirements be applicable only for the resolution of other licensees committed to meet the guidelines of miresolved disputed fire protection features. The stafT Section 9.5-1, " Fire Protection Program," of did not intend that the requirements be applicable to NUREG-0800, " Standard Review Plan" (SRP), w hich features that it had previously accepted. However, w hen inwrp rated the guidance of Appendix A to IrfP it issued Appendix R, the Commission decided, as a 1
Regulations, Guidance, and Inspection Procedures APCSil 9.5-1 and the criteria of Appendix R. 'lherefore, should be qualified by test to maintain the barrier plants licensed to operate after January 1,1979, can integrity under such conditions.
implement the guidance contained in SRP Section 9.5-1 to establish a fire protection program that complies with in addition. Position C.5 a, paragraph 3, specifies that 10 CFR 50.48 and GDC 3. In either case, the fire penetration designs should utilize only noncombustible pmtection programs are essentially equivalent from plant materials (see Section 5.8 of this report) and should be to plant. Ilowever, the regulatory process used to qualified by tests. The tests use the time-temperature establish the program can dilTer.
exposure curve specified by ASTM E-l 19.1he test acceptance criteria include:
s
'Ihe NRC guidance documents do not have the same status as NRC regulations or regulatory requirements.
(1) 1he penetration seal has withstood the fire Rather, the purpose of the guidance documents is to endurance test without passage of liame or ignition ensure the quality and uniformity of NRC stalT review s of cables on the unexposed side for the period of and to present a set of acceptable methods of complying time equivalent to the fire-resistance rating with the NRC regulations.1he guidance documents required of the barrier.
present solutions and approaches that are acceptable to the staff, but they do not represent the only possible (2) The temperature levels recorded on the unexposed approaches to solutions. Licensees can use approaches side are analy7ed and the maximum temperature that differ from those specified in the guidance does not exceed 325 "F.
document. In these cases, the staff perfonns more detailed review s to ensure that the ahemative approaches (3) 'the seal remains intact and does not allow are equivalent to the guidance.
projection of water beyond the unexposed surface during the hose stream test.1he hose stream can be 4.3.1 Appendix A to BTP APCSB 9.5-1 delivered through a 1 %-inch noule set at a discharge angle of 30 degrees with a noule in Position D.I.(j) of Appendix A to llTP APCSil 9.5-1, pressure of 75 pounds per square inch (psi) and a the stafT specified that floors, walls, and ceilings minimum discharge of 75 gallons per minute (ppm) enclosing separate fire areas should have a fire rating of with the tip of the noule a maximum of 5 feet 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br />. Penetrations in these fire barriers, including from the exposed face; or the stream can be conduits and piping, should be scaled or closed to delivered through a 1%-inch noule set at a provide a fire-resistance rating at least equal to that of discharge angle of 15 degress with a noule the fire barrier itself. In Position D.3.(d), the stafT also pressure of 75 psi and a minimum discharge of rpecified that cable and cable tray penetrations through 75 gpm with the tip of the noule a maximum of fire barriers should be scaled to give protection at least 10 feet from the exposed face; or the stream can be equivalent to that of the fire barrier itself.
delivered through a 2%-inch national standard playpipe equipped with a 1%-inch tip, noule 4.3.2 Standard Review Plan (NUREG-0800) pressure of 30 psi, located 20 feet from the exposed face.
In SRP Section 9.5-1, " Fire Protection Program,"
Position C.S.a, "lluilding Design," paragraph 3, the stafT 4.3.3 Generic Letter 86-10 stated that openings through fire barriers for pipes, conduits, and cable trays which separate fire areas should Generic Letter (GL) 86-10, " Implementation of Fire be sealed or closed to provide a fire-resistance rating at Protection Requirements," April 24,1986, provided least equal to that required of the barrier itself. In guidance for satisfying NRC regulatory requirements for conduits larger than 4 inches in diameter, openings fire protection. Enclosure I to GL 86-10 included should be sealed at the fire barrier penetration. In interpretations of Appendix R requirements.
conduits 4 inches or less in diameter, openings should be Interpretation 4, " Fire Area lloundaries," stated, in part:
scaled at the fire barrier unless the conduit extends at least 5 feet on each side of the fire barrier and is sealed The term " fire arca" as used in either at both ends or at the fire barrier with Appendix R means an area sufficiently noncombustible material to prevent the passage of smoke bounded to withstand the l fire] hazards and hot gases. Fire barrier penetrations that must associated with the area and, as necessary, maintain environmental isolation or pressure difTerentials to protect important equipment w ithin the area from a fire outside the area. In order 9
Regulations, Guidance, and Inspection Procedures to meet the regulation, fire area 5
TECHNICAL ASSESSMENT boundaries need not be completely scaled floor-to-ceiling, wall to-wall boundaries.
Ilowever, all unsealed openings should be 5.1 Rev.iew of Penetration Seal identified and considered [in] evaluating Part 21 Reports the effectiveness of the overall barrier.
Where fire area boundaries are not widt-NRC maintains a database of reports submitted in to wall, floor-to-ceiling boundaries with accordance with 10 CFR Part 21, " Reporting of Defects all penetrations scaled to the fire rating and Noncompliance." The stalT searched the database to required of the boundaries, licensees must find reports that involved penetration seal materials that perform an evaluation to assess the had been submitted since it completed its first adequacy of fire boundaries in their plants penetration seal assessment in 1988. The stair found only to determine if the boundaries will two Part 21 notifications. These were submitted by Dow withstand all hazards associated with the Corning Corporation?
area.
On November 17,1994 Dow Commg submitted a Part This regulatory position established that certain 21 notification cohcerning Dow Corning 96-081 RTV penetration seals need not have the same fire rating as Adhesive / Sealant and on Nevember 28,1994, it the barrier in w hich they are installed. Licensees evaluate submitted a Part 21 notification concerning such seals on a case-by-case basis. The engineering SYLGARD 170 Silicone Elastomer and SYLGARD 170 evaluations perfonned to assess the efTectiveness of the Silicone Fast Cure Elastomer. According to the penetration seals are based on the expected fire-resistive notifications, certain lots ohhe RTV Adhesive / Sealant performance of the seal and on the fire hazards and fire deviated from Dow Coming sales specifications for protection features in the fire area.
11ame self-extinguishing time and certain lots of SYLGARD deviated from Dow Coming sales 4.4 Inspection Procedures specifications for cure rata. Dow Corning also informed each ofits customers of the deviations.
NRC fire protection inspection procedures are contained in NRC Inspection Manual Inspection Procedure 64704, Later, on the basis ofits testing and analysis, Dow
" Fire Protection Program," March 18,1994; Inspection Coming determined that the deviations were traceable to and Enforcement Manual Inspection Procedure 64100, a pigment that was c<mtaminated with sulphur. Dow
" Post Fire Safe Shutdown, Emergency Lighting and Oil Coming also concluded that the deviations were limited Collection Capability at Operating and Near-Term to specific lots As part ofits technical review of the Operating Reactor Facilities," March 16,1987; and Dow Corning Part 21 notifications, the staff met with inspection and Enforcement ManualInspection Dow Coming representatives at NRC 1leadquarters Procedure 64150, " Triennial Post-Fire Safe Shutdown during a public meeting on January 31,1995. The staff Capability Reverification," March 16,1987.
also inspected Dow Corning facilities (see Section 5.6.1) and witnessed fire endurance testing activities that were The NRC inspection procedures do not give specific performed at UL to htermine if the deviations adversely guidance for inspecting fire barrier penetration seals.
impacted the fire-resiance performance of seals, if any, llowever, the stafT has routinely inspected fire barrier diat used the contaminatcJ component.
penetration seal programs during fire protection program and other inspections (see Section 5.3). Nevertheless, the 13y letter of July 21,1995, Dow Corning submitted the staff concluded that the lack ofinspection guidance UL fire test results. On the lusis of the fire endurance could be viewed as a potential weakness in the NRC tests, which consisted of sid eby-side tests of test reactor fire protection program. The stafTis now specimens constneted wiQ suspect and nonsuspect j
preparing the new Fire Protection Functional Inspection l
(FPFI) Program that it had described in SECY-95-034,
" Status of the Recommendations Resulting from O
'As explained in Section 5.6.1 of this report, the Reassessment of the NRC Fire Protection Program,"
deficiency reporting requirements of 10 CFR Part 21 are
)
February 13,1995. The staff will include guidance for not applicable to the products that Dow Corning supplied i
inspecting fire barrier penetration seal programs in the to nuclear power phmt fire barrier vendors. Ilowever,
^
FPFI procedures and guidelines for use by NRC Dow Coming has conservatively elected to inform the inspectors on an as-needed basis.
NRC and its customers of potential product deviations.
NUREG-1552 10
Technical Assessment materials, UL concluded that there were no significant problems concerning improper seal construction and d.ianons or irregularities in fire barrier performance failure to install seals occurred during original plant octween the penetration seal materials. UL also construction. In some cases, it appeared that licensees concluded that these materials would not be precluded may have conservatively reported such superficial from being used in UL-classified penetration seals. The problems as surface imperfections, and small cracks, staff reviewed the test results and concurred with the splits, and gaps. Such conditions would not have conclusions made by UL The staff also concluded that precluded the seals from perfonning their intended fire the material deviations regarding self-extinguishing time protection design function. In many other cases, the and cure rate do not have a significant afTect on material inherent fire-resistive capabilities of the penetration seal performance as a lire barrier. On the basis of its materials installed in nuclear power plants would have document review s, fire test observations, inspection provided some measure of fire protection. For example, activities, and discussions uith Dow Corning weaknesses with fire test documentation or missing a maimfacturing and corporate personnel, the staff also scheduled surveillance would not adversely impact the concluded that the actions taken by Dow Corning to fire-resistive capabilities of the penetration seals.
address the issues w cre appropriate, timely, and satisfactory.
The LERs did not indicate generie problems with penetration seal materials. In addition, the staff lound no 5.2 Review of Reactor Operating repons of sarety-signiticant railures or penetration seals.
On the basis ofits review of LERs, the stafTconcluded Expera.ence that licensee penetration seal surveillance programs have been effective in revealing penetration seal deficiencies.
5.2.1 Review of Licensee Event Reports The staff also concluded that licensees appeared to be taking timely and appropriate actions to correct Oak Ridge National Laboratory maintains a licensee identified discrepancies." It is the staft's opinion that event report (LER) database for the NRC. In 1994, the continued licensee surveillances in accordance w ith database contained about 58.0001.ERs that had been existing plant procedures are adequate to ensure that submitted since 1980. SNL searched the database in penetration seal problems are discovered and resolved.
1994 and found that 318 LERs, or about 0.5 percent of See also Section 5.3.
the LERs in the database involved fire banier penetration scalt in support of the assessment 5.2.2 Review of Reactor Fire Experience documented here, the staff searched the LER database and found that licensees for about 20 plant sites had The stalT reviewed the fire event databases compiled by submitted 14 i LERs related to fire barrier penetration SNL, w hich contained data from 1965 thorough 1985, seals between 1989 and 1993, inclusive." Since almost and the Electrie pow er Research Institute, w hich one-half of the LERs related to penetration seals have contair 4 data from 1965 through 1988. The staff found been submitted during this four year period. it appeared no reports of nuclear power plant fires that challenged that staff elTorts to alert licensees to potential penetration the ability of fire-rated structural barriers or fire-rated seal problems in 1988 (see Section 1.2) increased penetration seals to confine a fire in accordance w ith industry's awareness of penetration seal problems and their fire protection design function. The staff also resulted in more thorough surveillances. 'lhe types of reviewed the LER database discussed in Section 5.2.1, problems that had been reported by the licensees are which includes data from 1980 to the present, and again, shown in Table 2.
found no reports of nuclear power plant fires that caused the failure of a fire-rated structural barrier or a fire-rated The staff found that the predominant problems involved penetration seal.
improper installation, seal degradation, and seal breach.
Most of the problems associated with installed penetration seals involved seats constructed of silicone foam. To a lesser extent, problems involved the failure to install seals w here required. It appeared that most "This w as the period of time between when the staff "The staff also used the insights it gained from its had completed its first penetration seal assessment LER review to help plan the vendor and plant site (1988) md when it staned its substantive work on the inspections discussed in Sections 5.5 amt 5.6.
technical assessment documented here (1994).
1I NUREG-1552
~
Technical Assessment Table 2 Penetration Seal Problems Reported in LERs i
Reported Problems Number of LERs
% of total LERs Seal inoperable or deficient due to improper installation, 82 58 degradation, or seal breach 1
i l
Seal not installed or missing 37 26 Seal surveillances not performed 14 10 Inappropriate or unqualified penetration seats 6
4 Temporary or improper seal installed 2
2 Total number ofI.ERs 141 5.3 Review of Previous NRC that the licensee had addressed the seal degradation effectively, and the inspectors closed the unresolved Inspection Results item. Ai iP3, the inspectors had que iioned the methodology used by the licensee to detemiine the self-The staff reviewed region-based and resident ignition temperature of cables that pass through inspector-based reactor inspections that addressed penetration seals. Ilowever, the inspectors had found the penetration seal programs." These inspections are licensee's penetration seal analyses and supporting identified in Table 3.
documentation to be generally sullicient.
The inspections of Calvert Clif fs, Diablo Canyon (see The NRC is currently tracking corrective actions for Section 5.4.4), Ginna, Iladdam Neck, San Onofre, penetration seal deficiencies at Diablo Canyon and IP3.
Susqueharma, and Washington Nuclear Project 2 (see Section 5.5.5) w cre routine fire protection program The impection reports, like the I.ERs sununarized in inspections u hich included inspections of the penetration Section 5.2.1, revealed that licensees occasionally find seal programs. The inspections of Indian Point 3 (IP3),
plant-specific deficiencies; llowever, the inspection Oyster Creek, and River Bend Station (RBS) w cre reports also indicated that the licensees maintained special or routine resident inspector inspections. The satisfactory fire barrier penetration seal programs and inspectors reviewed the adequacy of penetration seal have taken appropriate and timely actions to correct any installations, qualification, and surveillances. They also penetration seal deficiencies found during surveillances.
followed up on issues reported in I.ERs and w eaknesses The NRC inspection report.s did not reveal widespread or noted during previous NRC inspections.
potentially generie problems of safety significance.
The inspection reports for San Onofre and Iladdam Neck stated that the licensees had completed penetration seal reevaluation programs in response to NRC and industry 5.4 Review of Plant-Specific concems regarding the adequacy of fire berrier Corrective Action Programs penetration seals in 1988. 'Ihe inspection reports indicated that these programs were comprehensive, The suff review ed the status of the penetration seal timely, and acceptable.
programs at several plants that had undenaken penetration seal corrective action programs since it At RBS, the inspectors had found that the licensee's completed the first penetration seal assessment. The staff corrective actions n ere not adequate in response ta the had origiudiv reviewed the programs for two of these i
misapplication of seal material in 1991. The seals were plants (Wolf' Creek Generating Station and V.C. Summer not designed for the high ambient temperatures to which Nwlear Smtion) during its first penetration seal they w ere exposed; therefore, the seals degraded. Later, ament. Two other plants (Vermont Yankee Nuclear during the 1995 inspections, the inspectors concluded Power Station and Diablo Canyon Nuclear Power Plant) initiated programs atter the stat! issued the infonnation notices in 1988 that addressed the findings of the first i
"Unlike the audits and inspections summarized in assessment.
Section 5.5, the staff did not conduct these inspections as part of this assessment.
NUREG-1552 12
Technical Assessment Table 3 NRC Inspections of Penetration Seal Programs Plant Report Dates Calvert ClitTs Nuclear Power Plant May 6,1994 Diablo Canyon Nuclear Power Plant Units I and 2 March 15,1994 and May 1,1995 R.E. Ginna Nuclear Power Plant June 13.1994 Iladdam Neck Power Station June 19,1995 Indian Point 3 Nuclear Power Plant July 26,1995 Oyster Creek Nuclear Generating Station July 21,1995 River Bend Station March 8, May 3, and June 9,1995 San Onofre Units 2 and 3 January 28,1994 Susquehanna Steam Electric Station July 31,1995 Washington Nuclear Project 2 February 25 and November 9,1994; and June 29,1995 The LERs discussed in Section 5.2.1, the NRC In 1987, the licensee had established a task force to inspections discussed in Section 5.3, and the develop. corrective action plan. The inspection plan plant-specific corrective action programs sununarized included the removal of damming boards and inspection below showed that the licensees knew and understood of accessible foam penetrations. The scope of the the fire resistive capabilities of the penetration seal program included inspections of more than 1700 silicone materials and configurations; potential penetration seal foam penetration seals. As a result of the inspections, the testing, design, installation, inspection, and maintenance licensee repaired more than 600 seals during 1987 Since problems; and possible remedies and corrective actions.
1987, the licensee has found only minor problems during
'Ihese findings also indicated that the actions taken by routine inspections. The licensee addressed these the r.aff in IN8 had increased industry an areness of problems promptly.
possible penetration seals problems, leading industry to more comprehensive inspections, maintenance, and 5.4.2 Virgil C. Summer Nuclear Station corrective actions.
In February 1987, after a vendor inspection at Brand 5.4.1 Wolf Creek Generating Station Industrial Services Company, Incoqw aied (see Section 5.6.2), the licensee for V summer Nuclear In December 1984, the licensee had issued a Station, had performed an evaluation of silicone foam nonconfonnance report because 22 penetration seals penetration seals. During the evaluation, w hich it lacked document traceability. The licensee had completed in July 1987, the licensee evaluated 642 sealt completed corrective actions in 1985. Later,in early it found that about 94 percent of the seals were 3-hour 1987, Promatec, the penetration seal installation qualified on the basis of fire endurance test results. It had contractor, notified the NRC that 20 of 40 seals inspected also accepted the configurations of 21 seals on the basis exhibited voids and shrinkage of the silicone foam of enginecting evaluations and modified 15 seals to material. It was found that the problems had involved achieve acceptable configurations.
installation methodology, inadequate quality control (QC) metbds, and rapid chemically induced silicone Problems identified earlier by visual inspections foam material expansion. The licensee issued LER 87-involved only minor degradation of the seal material, 010 on February 6,1987. Several other nuclear reactors these were readily repaired. During inspections of the were affected by this problem. Promatec infonned the fire protection program in 1987 and 1988, the regional industry of the problems and submitted a Part 21 stalTinspected a sampling of fire barrier seals and notification. Later, after the first penetration seal reviewed the inspection procedures u hich are used by assessment, the NRC had issued IN 88-56 to advise the licensee to perfonn periodic visual inspection ( No licensees of the problems discovered at Wolf Creek.
problems uere noted during these inspections.
13 NUREG-1552
l Technical Assessment 5.4.3 Vermont Yankee Nuclear Power and has clarified responsibilities for control of Station pendration seals. The staff had followed up on the licensee's activities during inspections in February 1994 i
on March 19,1992, during an inspection of fire barrier and March 1995. The inspectors concluded that the penetration seals at Vermont Yankee Nuclear Power licensee had taken appropriate corrective actions. The Station, the licensee found a penetration containing stalTis continuing to follow the licensee's actions.
i unapproved material. The next day, another penetration seal was found to be degraded. The licensee 5.5 Focused Audits and Inspections implemented compensatory measures and began an of Nuclear Plants i
investigation into the cause of the degradation.1 ater, w hile implementing corrective actions in in support of this generie assessment, the stafTaudited December 1992, the licensee found additional problems.
the penetration seal programs at Davis-Besse Nuclear it perfonned additional seat inspections and found that Pow er Station and Waterford 3 Nuclear Power Plant and the seal discrepancies w ere more widespread than inspected the penetration seal programs at Susquehanna l
originally believed. On January 15,1993, the licensee Steam Electric Station, Calvert Clifts Nuc! car Power issued LER 93-001. The licensee declared 57 penetration Plant, and Washington Nuclear Project 2 (WNP2). In seals inoperable and established a task force to inspect addition, as part ofits licensing review of the Watts Bar all fire barrier penstration seals. Ultimately, the licensee Nuclear Pow er Plant (WBN), the stalT review ed and repaired more than 900 of the 1400 fire barrier inspected the WBN fire barrier penetration seal program penetrations installed at Vermont Yankee and upgraded in detail.1he staff selected these plants on the basis of abnost 300 penetrations. The licensee attributed most of reports of problems (Davis-Besse, Waterford 3, and i
the as found unacceptable penetrations to inadequate Susqueharma), combination of old and new seal design or installations made by the installation contractor installations (Calvert Cliffs), significant corrective action between 1979 and 1980, ('lhe seal contractor is no program and rework by licensee after self-identification longer in business.) The licensee attributed the failure t of problems (WNP2), and new construction including identify these issues to madequate surveillance testing and engineering (WBN).
procedures. The licensee completed the repairs to atrected barriers and the required surveillances in During these audits and inspections, the staff May 1993.
(I) follow ed up on potential problems regarding fire barrier penetration seals; (2) gathered information on 5.4.4 Diablo Canyon Nuclear Power Plant qualified penetration seals; and (3) assessed w hether the j
seals w ere designed, tested, installed, inspected, and in January 1994, the licensee for Diablo Canyon Nuclear maintained in accordance w ith licensee commitments, l
Power Plant, found that certain fire barrier penetration NRC fire protection requirements and guidance, and I
seals may not have met the required 3-hour fire rating standard industry practice. The staff selected seals for because danuning boards w cre not installed on both inspection on the basis of several factors, including t
sides of silicone foam seals. This deficier.cy w as (1) seal type and material, (2) seal location, (3) seals that I
discovered and reported by utility construction personnel had been repaired or reworked, and (4) seals for which during routine repair of an existing penetration seal. The there w cre potential technical problems. The staff seal that needed the damming board w as repaired and an examined procurement documentation for penetration engineering review revealed that many of the silicone seal materials, seal compatibility with barriers in w hich foam seals needed damming boards to meet the 3-hour they w ere installed, fire endurance tests associated with criterion. A walkdown of additional seals was conducted the seal qualification designs, and training programs for and revealed approximately 100 representative silicone seal installers and inspectors, and review ed penetration foam tire barrier penetration seals with missinF amming seals installed at the plant sites, the QC and quality d
boards. The licensee initiated roving fire w atches as a assurance (QA) programs relating to installation and compensatory measure. It w as believed that this maintenance of penetration seals, deviations ofinstalled condition had existed since the plant was constructed. On seals from NRC requirements, and surveillance February 24,1994, the licensee issued LER l-94-001-00.
requirements and programs for tecimical specification penetration seals.
The licensee has established a program to qualify the penetration seals uith respect to fire endurance tests or During some of these audits and inspections the staff representative plant fire hazards, has completed found several minor weaknesses. Ilowever, the sta!T w alkdowns to document the adequacy of penetration seal concluded that the w eaknesses did not result in configurations, has review ed design and installation deficiencies w ith the installed penetration se ds. lhe staff procedures for penetration seals, has review ed did not find safety significant problems or potential engineering procedures and design change documents, problems with eneric implications. Moreover, during F
NUREG-1552 14
Tecimical Assessment these activities, the stalT found that the licensees and 5.5.5 Washington Nuclear Project 2 vendors are aware of and familiar with the possible problems that can exist with penetration seals, that fire In December 1993, the licensee for WNP2 started a test results and qualified fire-resistant penetration seal review of issues related to its penetration seal inspection designs and materials are widely available, and that program. The licensee found deficiencies w ith the licensees have the means to correct penetration seal original instdlations, periodic inspections, and repairs.
deficiencies and problems. The results of the plant site Licensee evaluations of the deliciencies involving audits and inspections are summari/ed below.
original seal construction found that some seals did not meet existing acceptance criteria and design drawings 5.5.1 Davis-Besse Nuclear Power Station and that work practices were not in accordance with the installation procedures.1he licensee identified five From May 9 through 12,1994, NRR staff audited the major contributing factors: (1) inadequate construction, penetration seal program at the Davis-llesse Nuclear (2) inadequate management methods, (3) inadequate Power Station. On the basis of the audit, the stafT design configuration and analysis (4) inadequate work concluded that the licensee had implemented and practices, and (5) inadequate training.1he licensee maintained an acceptable fire barrier penetration seal declared all penetration seals at WNP2 inoperable, j
program and that no significant problems existed with established compensatory measures, and initiated a l
the fire barrier penetration seal installations at comprehensive penetration seal upgrade program.
l Davis-Besse. The stafIdid not find infonnation that suggested problems with generic implications.
The penetration seal upgrade program included seal calculations backed by fire endurance tests; new seal 5.5.2 Waterford 3 Nuclear Power Plant design guide, typical seal details, and barrier functional list; revised plant specifications and procedures w hich NRR staff audited the Waterford 3 penetration seal reference the aforementioned documents; closure of program from July 11 through 14,1994. The stafT found penetration seal impairments; GL 86-10 engineering j
several minor w eaknesses with fire test results and evaluations for certain non-rated barriers; updated l
training records.1he stafT concluded, however, that the installation and surveillance pmcedurr for training seal fire barrier penetration seal program was satisfactory and installers and inspectors; and qualified ai operable that the discrepancies did not create any problems with penetration seals.
the penetration seal installations at Waterford 3. The l
stalT did not find safety-significant problems or evidence NRC Region IV had identified the penetration seal to suggest that generic problems existed with penetration problems as an unresolved issue pending completion of seals.
the penetration seal upgrade program and had conducted three inspections of the program (see Section 5.3). The l
l 5.5.3 Susquehanna Steam Electric Station inspectors had concluded that the licensee was taking aggressive corrective action to resolve this issue. Later, l
from August 7 through 17,1995,in support of the From January 30 through February 1,1996, NRR staff techmcal assessment documented here, an NRC inspected the fire barrier penetration seal program at mtegrated assessment team mspected the h,censee Susquehanna Steam Electric Station. The inspectors activities mentioned above. The team assessed licensee found the damming material missing from one elTectiveness in identifying issues, performing root cause penetration seal. The licensee took immediate corrective analyses, and implementing corrective actions.1he actions. The inspectors concluded that the licensee had inspection focused on the areas of maintenance and implemented and maintained an acceptable fire barrier engineering.1he team inspected activities involving penetration seal program. The inspectors did not find Procurement, storage, installation, quality control, and safety-significant problems or evidence of generic I ng-term maintenance associated with the installation problems with penetration sca*.5.
and maintenance of pe letration seals. The team l
"*I"d'O"' ** U"*"*** *""*"' P"'I """""* I" th*
i 5.5.4 Calvert Cliffs Nuclear Power Plant areas of receipt inspection and storage control, quality 9""
From February 13 through 15,1996, the NRR stafT The assessment team also considered the licensee's inspected the fire barrier penetration seal program at corrective action program on penetration seals to be a Calvert Cliffs Nuclear Power Plant.1he msPectors strength ~
concluded that the licensee had an acceptable fire barrier penetration seal program. The inspectors did not find safety-significant problems or evidence of generic problems. Ongoing licensee cfToits to improve the l
penetration seal program were seen as positive.
15 NUREG-1552
Technical Assesrment 5.5.6 Watts Bar Nuclear Power Plant or the quality of the services and materials that the vendors provide to the nuclear industry.
As part ofits licensing review of the WilN lire protection program, and in support of this technical 5.6.1 Dow Corning Corporation assessment, the staff reviewed and inspected the fire barrier penetration seal program for WilN in detail. As Dow Coming Corporation is the primary supplier of part of its review, the staf f observed a penetration seal silicone-based fire barrier seal materials to the nuclear fire endurance test program conducted by the licensee industry. The NRC inspected Dow Corning facilities in and Promatec (see Section 5.6.3). The stalT also Midland, Michigan, and Elizabethtown, Kentucky, reviewed the WilN engineering report on the penetration during March 23 through 24 and April 3 seal program, audited a number of typical seal details through 5,1995. The inspectors did not find any and the corresponding fire qualification test reports, and problems tha: could adversely alTect reactor safety and inspected in-plant penetration seal configurations.
detemuned that Dow Coming elTectively executed the portions of the product manufacturing controls that were The fire barrier penetration seal materials installed at reviewed.
WBN consist of silicone foam, silicone clastomers, and boot-type seals. Each mechanical and electrical fire A significant aspect of the inspection was the review of barrier penetration seal w as fabricated to a specific Dow Coming's processes and procedures for reporting design detail and each design detail is supported by one and resolving potential product defects (see also, or more fire endurance tests. In addition, for about Section 3.1). The inspectors determined that Dow 4 percent of the mechanical penetration seals, which Corning had not employed unique nuclear requirements deviated from the typical design details, the licensee for design, manufacture, testing, or supply of its silicone-
~,
performed additional engineering evaluations in based penetration seal products. Some customers had accordance with GL 86-10. The evaluations either contractually imposed the requirements of to CFR addressed the adequacy of the seals as designed or their Part 21 on Dow Corning for products supplied for use in adequacy to perform their intended design function on nuclear power plant fire barrier penetration seals.
the basis of the fire hazards and the fire protection iIowever, the inspectors determined that the seal features in the area.
products w cre neither safety-related nor basic components (as described in 10 CFR Part 21). Therefore, The staff had documented its review and evaluation of from a regulatory st.mdpoint, the deficiency reporting the WilN fire penetration seal program in Section 9.5.1, requirements of Part 2 I are not applicable, llow ever, the
" Fire Protection Section," of NUREG-0847, " Safety inspectcrs determined that the Dow Corning defect Evaluation Report Related to the Operation of Watts llar reporting system appeared to provide a mechanism for Nuclear Plant, Units I and 2." On the basis of its informing the fire barrier installation vendors of potential comprehensive safety evaluation of the WBN penetration deviations of the penetration seal materials manufactured seal program, the stafT had concluded that the program by Dow Corning Corporation.
satisfied applicable NRC requirements and guidelines.
5.6.2 Brand Fire Protection Services, 5.6 Vendor Inspections Incorporated
'the stalTinspected Dow Corning Corporation;Ilrand During January 1987, in support ofits first penetration Fire Protection Services, Incorporated; and il&B seal assessment, the stalT inspected Brand Industrial Progressive Materials and Technologi,, Incorporated Services Company (HISCO). The staff found that (Promatec),in support of this assessa st. In general, the penetration seal test documentation used by certain areas reviewed during these inspections were seal nuclear plants may not have represented the as-built
]
materials, dedication of commercial-grade seal materials, penetration seal configurations. The statTcommunicated i
storage and shelflife of materials, procurement this linding to the potentially afTected licensees and documentation control, quality assurance and quality included the issue in IN 88-04. Later, this issue w as I
control, design control, and methods for qualifying reviewed during NRC penetration seal inspections of penetration seal configurations. The inspectors also licensees (see Sections 5.3,5.4, and 5.5).
considered aspects of the vendors' programs that were in place during the 1980s, w hen most nuclear pow er plant illSCO is now lirand Fire Protection Services, penetration seals were installed, and timse that are in incorporated (Brand). In support of the assessment place today. As documented in the NRC inspection documented here, the stalT inspected Brand facilities in reports, and summarized below, the inspectors did not Addium, Illinois, from November 6 through 9,1995.
l find problems that could adversely alTect reactor safety The inspectors determined that the areas that were inspected were satisfactory. The inspectors did not find l
NUREG-1552 16
Technical Assessment issues that could adversely affect reactor safety or the inspect a portion of the total population of seals every quality of the services and materials that lirand provides refueling outage (about every 18 months). If penetration to its nuclear power plant customers.
seals are foum to be degraded or inoperable (e.g.,
breached, degraded, or improperly repaired), the 5.6.3 H&B Progressive Materials and licensees document the deficiencies and take appropriate Technologies, Incorporated wrmctive actions. If such conditions are found during pow er operations, the licensees establish such NRC-From December 6 through 9,1995, the stalTinspected appmved compensatory measures as fire watches until B&ll Progressive Materials and Technologies, the degraded condition is corrected.
Incorporated (Promatec), facilities in Cypress, Texas. As part of this inspection, the stalT also witnessed the During tlu.s assessment, the stafTreview ed procedures, construction and testing of 14 cable slot penetration seal specifications, and training programs for installation, test specimens at Omega Point Laboratories (OPL),
suncillance, maintenance, and repair of penetration seals Elmendorf, Texas. Six of the cable slots contained at both plant sites and seal vendor facilities. Most of the control and instrumentation cables, six slots contained Problems associated with installed penetration seals power cables, and two slots were empty spares (no cable f und by the staffinvolved silicone foam seals. Potential fill). The penetration seals consisted of fire-resistive innallaton problems melude voids within the seal, splits I
permanent damming boards and silicone foam. The test or gaps in f am caused by contaminat on or poor 1
specimens were subjected to a 3-hour fire endurance test installation techniques, and failure to find instell. tion 1
which confonned to the ASTM E-119 standard time.
Problems because they are hidden by permanent temperature curve followed by a fog nonle hose strearn damming matenais, test. The acceptance criteria ofIEEE 634 were used to Silicone foam and silicone clastomer seals with vo.ds or i
evaluate the fire-resistive performance of the seals. All of die test specimens met the acceptance criteria. On the holes can be repaired using like materials or silicone basis ofits observation of the construction and testing of caulk. In general, procedures developed by penetration the test specimens, and its review of the fire test reports, seal sendors for repair of silicone seals specify diat the stafT concluded that the silicone cable slot penetration rcPairs of holes or voids greater than 0.5 mch can be seals were acceptable for installation at WBN.
made using silicone caulk. Vendors have conducted satisfactory fire tests for this type of repair. Repairs of During its inspection of the Promatec facilities in holes or voids greater than 0.5 inch slauld be male Cypress, Texas, and the fire test program at OPL, the
"*I".g dm same mal matuial as eat useMo wndmet dm inspectors did not find problems that could afTect reactor ong nal penetratmn seat Us,ng matuials odmr than dm t
safety or the quality of the services and materials that nginal mal mataial wuld render the seal inoperable if i
Promatec provides to nuclear power plants. The um n paimd mnhguraten is not qualified by a fire test or inspectors determined that the areas inspected were justified with an engineering evaluation. For example, if satisfactory.1his inspection also provided a real-time a seal f a given depth and given seal matenal density example of a penetration seal vendor's ability to conduct was quaEmd as a 34mur seal, it may not be acceptable I use a difTerent seal matenal to repair the ongmal seal 1
a satisfactory penetration seal fire test program.
}
unless the altenative matenal was qualified m, a smular configuration.
5.7 Installation, Surveillance, Maintenance, and Repair Altimugh the stafTobserved several minor weaknesses dur;ng some ofits plant site inspections, it did not find j
Proper installation, surveillance, maintenance, and repair evidence that the weaknesses resulted in problems with are important to the ability of penetration seals to installed penetration seals. Overall, the stalT concluded 4
i perform their intended fire protection design function.
that licensees and vendors are awa;, of the i.nportance of Potential problems include (1) incomplete or inadequate Proper design, installation, surveillance, maintenance, a
fire test documentation, (2) in-plant penetration seal and repair of penetration seals, including installer and configurations not bounded by fire tests,(3) seals not inspector training. During its review of repair records installed w here required,(4) seals not installed properly, and plant walkdowns, the staff did not find any instances (5) seals not repaired, (6) seals repaired improperly, of repairs using improper or dissimilar seal materials.
(7) seals modified witimut a supporting engineering evaluation, and (8) seals not inspected in accordance The stafT had previously addressed potential problems in with plant surveillance procedures.
IN 88-04,IN 88-56, and IN 94-28 (see Appendix A). On the basis of the assessment docuaented here, it is the The licensees have fire barrier penetration seal staffs view that existing licensee and vendor seal surveillance and maintenance programs that are installation programs are adequate to prevent potential governed by written procedures. In general, the licensees Penetration seal installation problems. In the event seals 17 NUREG-1552 k
Technical Assessment are improperly installed or breached, or become (such as fire-resistant damming boards), if any, and the degraded, existing licensee surveillance, maintenance, air supply present. For the typical nuclear power plant and repair programs are adequate to reveal and correct design, silicone-based penetration seal materials potential problems.
contribute only a little to the overall combustible load in tenus of both quantity of material and surface area. For
"*P ' i" "'""Y ""'l'"' P"" P ant fire areu, the l
l 5.8 Combustibility of Silicone-Based surf ace area of the penetration seals is much less than the Seal Materials surface area of the cablejackets in the vicinity of the seals. In addition, the potential amount of fuel that can Although silicone-based penetration seal materials are be contributed by silicone-based penetration seal fire resistant, they are classined as " combustible" w hen materials is less than the fuel that could be contributed tested in accordance with ASTM E-136, " Behavior of by the cablejacket and insulation materials. Moreover, Materials in a Vertical Tube Furnace at 750 "C,"" which despite the fact that a silicone-based penetration seal is a combustibility test method accepted by the NRC. It assembly could contribute some fuel to a fire,its relative has been asserted that silicone-based seals should not be contribution to the overall tire severity would be installed in nuclear power plants because (1) NRC fire negligible.
protection regulations prohibit the use of combustible materials in nuclear pow er plants and (2) Appendix R In the unlikely event that a large fire exposes a silicone-and the SRP specify that penetration seat materials be based penetration seal to high temperatures for an noncombustible.
extended period of time, the silicone-based material will decompose and be replaced with char or ash. Due to the Section 50 48 of 10 CFR part 50 does not address the nature of the silicone-based materials and the limited air use of combustible materials. GDC 3 states that supply present within the seal assembly (as opposed to noncombustible and heat-resistant materials shall be used the air present around the burning combustibles outside w herever practical throughout the unit, particularly in the seal), the propagation of the fire through the seal locations such as the containment and control room.
assembly will be very slow. Again, this has been llowever, GDC 3 does not preclude the use of observed during and demonstrated by full-scale combustible materials. Examples of combustible qualification fire endurance tests of a wide variety of materials that are installed in nuclear power plants are silicone-based penetration seal c(mngurations? These cable insulation and cable jacket materials, diesel tests have also demonstrated that silicone-based seals cra generator fuel oil, turbine-generator lubricating and provide the necessary fire resistance and the reasonable hydraulic control Huids, reactor coolant pump assurance that a fire will not spread from one side of the lubricating oils, charcoal and other filters, and llanunable fire barrier to the other in conngurations where cables, gases and liquids. In general, w hen such materials are pipes, conduits, ducts, and other combustible and properly managed. are accounted for in the plant design noncombustible entities penetrate the silicone-based and operation, and are incorporated as integral penetration seal.
components of the plant fire protection program, including the fire hazards analysis, they are acceptable.
Silicone foam and silicone clastomer can be combined with other materials to fonn radiological shields; fill
'ihe staff evaluated the potential fire hazards associated complex irregular openings (e p., around cables in cable with silicone-based penetration seal assemblies and trays) and adhere to the penetration and the penetrants; concluded that properly tested, conngured, installed, and cure rapidly; and can be removed and restored to their maintained silicone-based penetration seal assemblies are original effectiveness (e g., w ben making such plant not credible fire lwards. Silicone-based penetration seal modineations as installing new cables); have high-materials are usually distributed throughout the fire area temperature stability; are Desible: and resist the effects (as opposed to representing concentrations of of radiation exposure and aF ng. Silicone clastomers can i
combustibles), are relatively difficult to ignite, and burn also be used as Good and pressure seals A wide variety slow ly. The rate of combustion and name propagation of silicone-based penetration seal designs have been depends on factors such as seallocation and tested and listed by material manufacturers and
~
connguration, total mass, surface area, surface coverinF installers: by UL in its Fire Resistance Directory and by FM in its FactoryManalSystem <lpprovalGuide. It is also notable that other countries. government agencies, "Dow Corning Corporation had reported the results j
of ASTM E-136 tests in a paper entitled Tiammability l
Characteristics of a New Silicone RTV Foam," Kathy M.
"For example. when exposed to an ASTM E-119 fire, Kelly, Society of plastics Engineers, progress in plastics w hich is a severe fire exposare, silicone foam burns at a Through Education 34th Annual Technical Conference, rate of about 3 inches of thickness per hour. Silicone April 26-29,1976, Atlantic City, New Jersey.
clastomer bums at a slower rate.
NUREG-1552 18
I Technical Assessment insurance bodies, and building codes accept the use of fomiula to improve the manufacturing process by l
silicone-based penetration seals. For these reasons, allowing wider tolerances for the amounts of several of silicone foam and silicone clastomers are accepted for the basic ingredients used in the foam.
l use in penetration seals in a wide variety of residential, commercial, and industrial buildings u here fire-resistive To demonstrate that the fire resistance of the modified separation is needed."
fonnulation was equivalent to that of the old fonnulation, Dow Corning conducted comparison tests at 1he stalTeoncluded that qualified silicone-based fire Construction Testing Laboratories (CTL). The stalT barrier penetration seals can accomplish their intended reviewed the results of five 3-hour fire endurance tests design function and are not credible fire hazards. The (10 test specimens) and supporting infonnation stafT also concluded that the benefits of the silicone-regarding the fonnulation change to detennine if the based penetration seal materials outweigh any potential change adsersely affected the fire-resistive performance concerns regarding material combustibility.
of Dow Coming 3-6548 Silicone RTV Foam in the tested configurations.
1he stafT also reviewed the requirements of Appendix R i
to 10 CFR Part 50 and the guidance of SRP The test specimens were subjected to the standard time-Section 9.5.1. The staff reviewed the record for temperature fire exposure specified in ASTM E-119.
Appendix R (and interview ed the principal author of Ilose stream tests were perfonned at the end of the full Appendix R) and found no technical basis for including 3-hour fire exposure and used a solid hose stream. On the noncombustibility criterion in Appendix R. The the basis of its review of the test reports, the stalT noncombustibility criterion is included in the SRP concluded that the tests were conducted in accordance because the SRP simply embodied the criterion of with accepted industry standards. On the basis of its Appendix R. The stafT uoted that the noncombustibility evaluation of interface, cable, cable tray, and seal criterion is not included in llTP APCSB 9.5-1, temperatures, the thicknesses of unburned silicone seal Appendix A to llTP APCSB 9.5-1, or the industry fire materials, and the other observations documented in the endurance test standards. The ability of a particular test reports, the stalT conchided that the change in penetration seal to achieve its intended design function formulation of Dow Corning 3-6548 Silicone RTV Foam (i.e., to contain a fire), as determined by a fire endurance did not materially affect the fire-resistive perfonnance of test conducted in accordance with an industry standard the 'oam in the tested configurations. The stalT also (see Section 3.1), is the foremost design consideration. In concluded that the tests were an appropriate method for addition, because of the severity and duration of the fire assessing the etTects of the formulation change.
exposure, the industry standards would ensure that fire-resistant seal materials are used and would preclude the 5.10 Aging and Shrinkage qualification of materials that present lire hazards. 'lhe stafT recommends, therefore, that the material in its letter report entitled " Aging of Fire Barriers in noncombustibility enterion be removed fnnn Nuclear Power Plants," September 30,1994, SNL Appendix R and the SRP.
reponed that many fire barrier materials are resistant to thennally accelerated aging and that the material 5.9 Dow Corning Corporation properties or silicone-based materials, which dominate Silicone Foam Formulation the industry, are particularly age independent. SNL conclud'ed that these materials are not expected to exhibit Change problems as they age. Moreover, on the basis of its review of operating experience and the tecimical in a letter of November 12,1984, Dow Corning literature, SNL. did not find any penetration seal informed its customers that it had refornmlated Dow problems that were directly related to aging. SNL Corning 3-6548 Silicone RTV Foam. During a meeting reported that it did not find infonnation on thermal aging with the stafTon January 31,1995, Dow Coming representatives informed the stalT that it changed the
The NRC staff reviews nuclear power plant fire protection features within the scope of nuclear power "There are configurations for which silicone-based plant-specific applications after the licensee has materials may not be appropriate. For example,it may determined that the feature meets NRC regulations and l
not be appropriate to seal a diesel generator exhaust pipe its licensing commitments. Therefore, staff comments penetration with silicone foam because during operation on the CTL tests should not be interpreted as NRC staf f I
the exhaust pipe could exceed the upper temperature approval or rejection of the test results for specific I
limit for the silicone foam (see IN 88-04, Supplement 1).
nuclear power plant applications.
19 NUREG-1552
Technical Assessment or radiation testing of grout, cement, and gel-type seals.
immediate vicinity of the cablejacket (the silicone SNL did not recommend an experimental aging program.
material is affected but the cablejacket is not). Seal installers prevent this condition by coating the cable The stalT review ed additional infonnation on shrinkage jackets with a releasing agent before installing the of silicone foam penetration seals after they are installed.
penetration seal materials.
As discussed in Section 2.2, some shrinkage is nonnal.
Dow Corning, the major manufacturer of silicone-based During its vendor inspections, the stafT found that seal materials, has informed its customers that shrinkage materials vendors are w cll an are of conditions and occurs and has stated that shrinkage at interfaces of %-
circumstances that can cause curing problems and take inch-wide or less while extending not more than one appropriate steps to avoid or correct such problems. For third of the seal thickness (into the seal) is acceptable for example, the vendors have strict controls on the fillers fire protection purposes. On the basis of the information and other ingredients that they use in their penetration that the staff has reviewed, and the experience of the seals. the vendors also send random samples of the industry regarding shrinkage in silicone penetration materials they receive to independent laboratories for seals, the stafT has concluded that normal shrinkage does amdysis against their design specifications and test not have a significant impact on the function and samples of their finished products for structure and capabilities of silicone foam or elastomer as a fire barrier density, to ensure that they have cured properly.
penetration seal material.
The staff also reviewed this issue during its plant site It is the stalTs position that vendor and licensee audits and inspections. The staff addressed a potential penetration seal surveillance and repair programs, as problem that material impurities could have affected the described in Section 5.7, are adequate to address original installation of penetration seals. The inspectors potential penetration seal problems associated with seal found that sullicient material controls were in place aging and shrinkage.
during the installation of penetration seals to prevent cure inhibition. Evidence ofincomplete curing, such as 5.11 Silicone-Based Material Curing ald flaw (a slow flowing or creeping orthe seal material from the penetration due to retarded or As part of this assessment, the staff considered potential inc mplete curing) or other seal deficiencies, was not curing problems in silicone-based penetration seal f und in direct seal inspections by the NRC, or in the materials. Vendors may add ingredients (such as lead seal surveillance records review ed by NRC inspectors.
fines and iron oxide) to the basic silicone components to Interviews witu licensee and vendor personnel indicated impart special properties to the finished penetration seals that these types of problem were rare, and most (such as radiation shielding). Silicone foams, clastomers, personnel ould not recall having ever encountered such l
and gels use a platinum catalyst that causes the two pr blems.
components to react and solidify. The catalytic in its reviev, oil.ERs (see Section 5.2), the staff found mechanism can be adversely affected by moisture and i
contaminants. Sulphur is the most prevalent no repmts of pr blems related to lead content, cure time, contaminant. When present at high enough levels,
" f*".cti ns between cablej,ackets and penetratmn seal sulphur can inhibit the curing of silicone-based materials matenals. Although certam cablejacket matenals can during penetration seal installation. Some amines can inhibit or prevent curing at the cablejacket-scal also inhibit cure. In one case that the stafTis aware of, a mterfaw, the stalT fotmd no operating experience to seal vendor tested a sample of a filler product from a indicate that this is a problem within industry. It has been supplier and found it to be satisfactory according to the asserted by some that cure inhibition is created simply by the addition oflead fines to the silicone materials.
vendor's specifications. It was later discovered that the Ilowever, f r the reasons stated above, this assertion vendor received an inferior product from the supplier, and the sample that the vendor tested was not appears to be wrong.
representative of what it had received. The use of this contaminated filler led to curing problems in some The stalT concluded that industry, including material silicone products. Dow Corning has experienced cure manufacturers, penetratmn seal installers, and licensees, time deviations with its96-081 RTV Adhesive / Sealant, am ud aware of the potential causes and problems associated with cure inhibition.
SYLGARD 170 Silicone Elastomer, and SYLGARD 170 Silicone Fast Cure Elastomer (see Section 5.1). These problems were also traced to sulphur contamination.
5.12 Comparison of Tested to As-In addition to cure inhibition that can be caused by material contamination, certain cablejacket types can As discussed in Sections 3 and 4 of this report, to prevent silicone seal materials from curing in the pmvide reasonable assurance that a fire barrier a
NUREG-1552 20
Technical Assessment penetration seal can accomplish its intended fire On the aforementioned bases, the staff reconunends that protection design function, a penetration seal test guidance be included in any future fire protection assembly is subjected to a fire endurance test. 'Ihe guidance document (e g., a regulatory guide) to clarify accepted industry standards specify that the penetration the important parameters for designing and qualifying seal test specimens be representative of the design and fire barrier penetration seals. Examples of the design construction for w hich a fire ratig is desired. Ilow ever, considerations that could be included as guidance are in view of the large numbers of posdble penetration seal presented in the follow ing subsections. 'Ihese configurations that are installed throcehout the nuclear considerations are not existing stalTpositions, but are industry (e.g., a change in the cable fill in i; cable tray proposed as starting points for preparing guidelines that penetration represents a change in configuration), the could be used for designing fire test programs, for stalT recognized that it was not practical to test and assessing fire test results, and for performing engineering qualify each and every penetration seal configuration evaluations of penetration seal designs installed in the j
installed in nuclear pow er plants. Therefore, the staff has future.
l accepted die results of fire test programs that included a limited selection of test specimens that had been 5.12.1 Size of Scaled Opening specifically designed to encompass or bound the entire population of in-plant penetration seal configurations.
In some cases, a successful fire endurance test of a particular fire barrier penetration seal configuration for a Using such test results, licensees and vendors have particular size opening may be used to justify the same performed engineering evaluations (such as those contiguration for smaller openings. The converse may addressed in GL 86-10) to demonstrate that in-plant tire not be true.
barrier penetration seals are comparable to or bounded by fire-tested configurations. In some cases, the vendors 5.12.2 Penetrating Iterns or licensees had used the results of two or more fire endurance tests to justify a single in-plant penetration in some cases, a satisfactory test of a seal configuration
~
seal configuratmn. In such cases, the engineermg that contains a particular pattern of penetrating items can evaluation that the licensee had performed to justify the be uwd to quMify variations of the teued pattern.
in-plant seal design considered the results of fire tests Ior Variations that may be acceptable without additional l
a number of test specunens that were similar but not testing include eliminating or repositioning one or more identical to the m-plant seal assembly. Design of the penetrating items, reducing the size (cross-parameters and attributes that should have been wiond m) of a particular penetrating item, or ccmsidered m such evaluations are not explicitly stated in increasing the spacing between penetrating items.
existing NRC fire protectmn regulations or review Ilow ever, because penetrating items provide structural guidance. It is the stafl's opinion that, in general, the fire support to the seal, the free area of the seal material and test standards themselves and good engineering practice the dimensions of the largest free span may also be were adequate to identify the penetration seal design factors that alTect the fire-resistive perfonnance of the parameters that should have been considered m such seal assembly. In some cases, the thickness of the seal engineering evaluations. Nevertheless, the lack of material needed to obtain a particular fire rating may also specific NRC review guidance for comparing tested be a function of the free area or the distance between the configurations to as-built c(mfigurations can lead to penetrating items and outside edge of the seal assembly, techmeal questions regardmg the adequacy of a.
takes on specialimportance because of the heat sink they In other cases, consideration of the penetrating items particular seal design. Ilus is a potential, albeit mmor, weakness in the NRC fire protection program pmvide.
As part of the assessment documented here, the staff 5.12.3 Cable Type and Fill revisited a draf.t version of. IN 88-04 that it had prepared in 1987. The draft contained general considerations about the use of fire test results to qualify tire barrier I".smne can a satisfactory test of a seal configmation with certain electneal penetratmns contauung a specified penetration seal designs. Even though these cable fill ratio (cable cross-sectional area divided by the censiderations were not included in the final version of e tray or conduit cross-sectional area) and cable ty pe ca the infonnation notice, the draft infonnation notice appears to be widely available to industry. In addition, IP""?r, contml, or mstrumentation) can be used to quahly sinular contigurations contammg the same or a industry fire protection engineers infonned the stalT that sm lier cable fill ratio and the same cable jacket matenal some licensees follow the considerations stated in the draft infonnation notice even though the staff did not or a less gmbustible jacket material. The thennat conductivity of the penetrating cables is also important.
issue them.11iis indicates that such guidance would be 12 r example, a penetration seal fire test of a cable tray useful to the industry f or future penetration seal design with a 30-percent power cable fill would be more evaluations.
21 NUREG-1552
Tecimical Assessment Technical Assessment challenging (thennally) than a test of a tray with a 5.13 Comparison of Thermo-Lag 30-percent instmmentation cable fill due to the higher g
thennal mass of the power cables.
Seals 5.12.4 Damming Materials During this assessment, it was reported that there are The fire-resistive perfonnance of a given seal similarities between Thermo-Lag fire barriers and configuration can be improved if a fire-resistant penetration seals with respect to technical issues and damming material covers one or both surfaces of the potential problems. The staff evaluated these assertions.
seal. A satisfactory test of a seal configuration without a pennanent fire-resistant dam can be used to qualify the The principal purpose of1henno Lag fire barriers i
same configuration w ith a permanent fire-resistant dam, ditTers from that of penetration seals. 'Ihenno-Lag fire I
all other seal attributes being equal. The converse is not barriers are typically used to enclose one train of I
true.
redundant electrical cables that are located in the same plant fire area and needed to achieve and maintain 5.12.5 Configuration Orientation shutdown after a fire. The intended design function of the Thenno-Lag banier is to provide reasonable L
A satisfactory test of a particular seal cordiguration in assurance that the safe-shutdown train it encloses will the horizontal orientation (with the test fire below the remain free of fire damage despite the fire and, therefore, seal) can be used to qualify the same configuration in a will remain available to achieve shutdown." Penetration vertical orientation if the symmetry of the design seals are used to close openings through such structural configurations are comparable. For example, if a fire barriers as walls and floor-ceiling assemblies. The nonsymmetric penetration seal configuration (e.g., a seal intended design function of the penetration sealis to with a damming board on the bottom, but not on the top) confine a fire to the area in which it started and to protect is qualified for a floor-ceiling orientation with the important equipment within the area from a fire outside danuning board on the tire side of the test specimen the the area. This difference in design function is significant.
configuration could only be qualified for a w all Protecting the functionality of a component located orientation if a damming board w as installed on both within a relatively smalllhenno-Lag enclosure (as sid. 4 of the seal or if the potential fire haf ard is limiteJ compared to the volume of the fire area), which is to ts % with the danuning board.
designed to be totally engulfed in a fire, is technically more challenging than preventing the spread of fire 5.12.6 Material Type and Thickness through a fire-resistive barrier that is exposed to the fire on only one surface.
Satisfactory testing of a particular seal configuration with a specific seal material thickness can be used to Thermo-Lag fire barriers, which wcre manufactured and qualify the same configuration with a greater seal tested by one company, Thermal Science, incorporated material thickness of the same type of seal material.
(TSI), have been installed in most plants. In 1991, when iIow ever, the converse is not true.
the staff 11rst identified generic concerns with 1henno-Lag fire barriers, it questioned the validity of the 5.12.7 Type Testing available fire test data and the fire-resistance ratings of the lhenno-Lag fire barriers. For example, the sta!T j
In cases in u hich a single test of a particular seal could not fnd evidence that Thernm-1.ag had been tested configuration is to serve as a qualification test for the and certified as a fire w rap by third-party testing same or similar design configurations with different laboratories, such as FM and UL. (Although such tests design parameters, the tested conliguration should be the are not required by the NRC, the results of such tests can worst-case design configuration with the worst-case help establish the capabilities and limitations of products combination of design parameters. This would test and absent other credible information and data.) Conversely, qualify a condition that would fail first, if failure occurs a number of companies manufacture, test, and install
(
at all. Successful testing of the worst-case condition can penetration seals and a larFe number of penetration seal then serve to qualify the same or similar design designs and penetration seal materials have been tested configurations for design parameters within the test and approved by UL and FM.
range. In some cases,it could be appropriate to conduct multiple tests to assess a range of design parameters.
" Fire barriers that are used to enclose safe shutdown equipment are commonly called " fire wraps."
NUREG-1552 22
Technical Assessment in addition, in 1991, there wcre questions regarding the (4)
The general condition of penetration seal test standards, methods, and acceptance criteria that had programs in industry (licensees and vendors) been used to conduct fire endurance tests of the appears to be satisfactory.
Thenno-Lag fire barriers for the protection of electrical raceways. On the other hand, at that time, industry (5)
P'an%pecific deficiencies have been, and will consensus test standards, methods, and acceptance centinue to be found on occasion during criteria for determining the fire-resistance ratings of licensee surveilhmees and NRC inspections.
penetration seals had existed for decades. Furthennore, Fire protection defense in depth provides fire endurance tests conducted by the staff and the reasonable assurance that such deliciencies will nuclear industry after the staff raised concerns about not present an undue risk to public health and Thermo-Lag revealed that many Lenno-Lag fire barrier
- safety, configurations, even w hen installed in accordance with the procedures recommended by the vendor, could not (6)
A large body of fire endurance tests has estab-achieve their intended fire-resistance ratings. Dese tests lished the fire-resistive capabilities of the also demonstrated that certain Thenno-Lag fire barriers penetration seal materials, designs, and confi-were susceptible to structural failure. Com ersely, a large gurations installed in nuclear power plants. He body of qualification-type fire endurance tests of a wide test results support the conclusion that the variety of penetration seal materials and designs that are regulatory requirements can be met by these used in the nuclear industry have been successfully materials.
completed by various manufacturers, installer s, and test laboratories. On the basis of its direct observations of fire (7) 11 penetration seals are properly designed, endurance tests and its reviews of numerous fire tested, configured, installed, inspected, and endurance test reports, the staff has concluded that maintained, there is reasonable assurance that suitable fire endurance tests have established the fire they will provide the fire resistance of the tested endurance ratings of a large number of fire barrier configuration, maintain the fire-resistive penetration seal designs, configurations, and materials.
integrity of the tire barriers in which they are Properly designed penetration seals are not susceptible to installed, and confine the fire to the area of structural failure.
origin."
On these bases, the staff concluded that the technical (8)
Operating experience and inspection results issues and potential problems associated with fire barrier show that the licensees and vendors understand penetration seals and Thenno-Lag fire barriers are not the fire-resistive capabilities and limitations of comparable. He staff also concluded that the the penetration seal materials and Thermo-Lag experience does not in any way provide configurations; potential penetration seal bases for questioning the ability of fire barrier testing, design, installation, inspection, and penetration seals to achieve their fire protection design maintenance problems-and possible remedies function.
and corrective actions.
6
SUMMARY
OF FINDINGS (9)
The tenn " nationally recognized testing laboratory" is undefined and obsolete. There is need for the NRC fire protection guidance to n
(1)
Fire barrier penetration seals are not unique nuclear components. They are universally accepted for use in residential, conunercial, and industrial buihlings wherever fire-resistive separation is needed.
n,,Pmperly tested" means that a representative seal had been tested in accordance with an accepted fire (2)
There are no reports of fires that challenged the endurance test standard. " Properly conhgured" means ability of nuclear power plant fire-rated that the design of the mstalled seal had been detennmed
)
structural barriers or fire-rated penetration seals by a fire test and/or an engineering evaluation. " Properly to confine a fire.
inst:dled" means that the seal had been installed in accordance with the methods and procedures used to (3)
Here is no evidence of problems with the construct the test specimen (typically the seat vendor's materials used to construct nuclear power plant recommended installation procedures). " Properly fire barrier penetration seals.
maintained" means that the quality and configuration of the barrier had been maintained through routine surveillances and, as appropriate, maintenance and repair.
23 NUREG-1552
Findings reference fire endurance tests by a nationally and continued NRC inspections are adequate to maintain recognized testing laboratory, public health and safety.
(10)
There is no basis for the criterion in The technical assessment documented here has been the Appendix R and the SRP that specifies that subjeci of substantial public and industry interest. He penetration seal materials be noncombustible.
staffinformed the Commission of the findings of this report in SECY-96-146, " Technical Assessment of Fire (II)
Overall, satisfactory stalT review guidance and llarrier Penetration Seals in Nuclear Power Plants," dated industry practices, methods, and procedures are July 1,1996. (See Appendix E.)
available and are used to meet the regulatory requirements for fire barrier penetration seals.
8 RECOMMENDATIONS New guidance for comparing fire tested seal configurations to as-built configurations may be (1)
Revise the NRC fire protection guidance useful to the industry.
documents to reflect the current NFPA position (12)
The potential problems that were raised about penetration seals have been addressed. He staff (2)
Remove the noncombustibility criterion from did not find safety-significant plant-specific Appendix R to 10 CFR Part 50 and SRP Section problems nor did it find problems with potential 9.5.1. (Section 5.8) generic implications.
(3)
Develop and issue guidance for comparing fire 7 CONCLUSIONS test configurations to as-built configurations.
(Section 5.12)
On the basis of the totality of the information it found and assessed, including the " Report on the Reassessment (4)
Make this technical assessment report available of the NRC Fire Protection Program" that had been to the general public and industry.
conducted by NRR, the review of fire barrier penetration seals that had been conducted by AEOD, reports that had 9 BIBLIOGRAPilY been prepared by SNL on the population of fire barrier types installed in nuclear power plants and penetration American Nuclear lasurers, Standard 4n6, "NEL-seal aging, and the other documents referenced here, the PIA /MAERP Standard Method of Fire Tests of Cable staff concluded that the general condition of penetration and Pipe Penetration Fire Stops."
seal programs in industry is satisfactory. The staff did not find plant-specific problems of safety significance or American Society for Testing and Materials, Standard concerns with generic implications.
E-84," Standard Test Method for Surface Burning 1
Characteristics of Building Materials "
Even though the staff found the condition of penetration seal programs in industry to be satisfactory, it expects American Society for Testing and Materials, Standard i
that plant-specific deficiencies will occasionally be E 119," Standard Test Methods for Fire Tests of found during future licensee surveillances and NRC Building Construction and Materials "
inspections. Ilowever, potential fire barrier penetration seal problems are understood; indust y consensus fire American Society for Testing and Materials, Standard test standards are available and are followed; and fire test E-136, " Behavior of Materials in a Vertical Tube results and qualified fire-resistant seal materials and Fumace at 750 *C."
designs are available. Herefore, licensees have the
/
means to correct problems, and staff oversight will American Society for Testing and Materials, Standard continue to ensure corrections on a case-by-case basis.
E-814," Standard Method of Fire Tests of Through-Fire protection defense in depth provides reasonable Penetration Fire Stops."
assurance that such deficiencies will not present an undue risk to public health and safety. Finally, the stalT Dow Corning Corporation, " Flammability concluded that the actions it had taken in 1988 and 1994 Characteristics of a New Silicone RTV Foam," Kathy M.
to address potential penetration seal problems increased Kelly, Society of Plastics Engineers, Progress in Plastics industry awareness of such problems and resulted in urough Education,34th Annual Technical Conference, more thorough smveillances, maintenance, and April 26-29,1976, Atlantic City, New Jersey.
corrective actions. These actions together with continued licensee upkeep of existing penetration seal programs NUREG-1552 24 a
l Bibliography Dow Corning Corporation, Fonn No. 10-003-82, Pacific Gas and Electric, Letter of February 24,1994, to "Information About Materials for High Technology NRC Document Control Desk, submitting Licensee Applications: Dow Corning 96-081 RTV Event Report 1-94-001-00: " inadequate Fire Barriers l
l Adhesive / Sealant."
Penetration Seals Resulting From a Lack of Darmning Boards."
l Dow Corning Corporation, Letter of November 12, 1984, to Dew Corning Power Applicators, armouncing Pacific Gas and Electric, Letter of August 11,1994, to fonnulation change in Dow Corning 3-6548 Silicone NRC Document Control Desk, submitting Licensee l
RTV Foam.
Event Report 194-001-01: " inadequate Fire Barrier l
Penetration Seals Resulting From a Lack of Damming Dow Corning Corporation, Fonn No.10-051B-86, lloards due to Programmatic Deficiency."
"Information About Materials for iligh Technology Applications: SYLGARD 170 A & B Silicone Sandia National Laboratories, Letter Report of Elastomer "
May 29,1992, from William Lowrey, to NRC,"A Determination of the Population of Fire Barrier Types in Dow Coming Corporation, Form No. 61-320F-93, Generating Stations."
"Infonnation about Dow Corning 3-6548 Silicone RTV Foam."
Sandia National Laboratories, Letter Report of September 30,1994, from Tina J. Tanaka, to NRC, Dow Corning Corporation, Letter of November 17,
" Aging of Fire Barriers in Nuclear Power Plants."
1994, to NRC Document Control Desk, regarding a Part 21 notification concerning Dow Coming 96-081 RTV Underw riters Laboratories, Incorporated, Fire Resistance Adhesive / Sealant.
Directory,1995, Volume 2.
Dow Corning Corporation, Letter of November 28, Underw riters Laboratories, incorporated, Standard 1479, 1994, to NRC Document Control Desk, regarding a
" Standard for Fire Tests of nrough-Penetration Fire Part 21 notification concerning SYLGARD 170 Silicone Stops."
Elastomer and SYLGARD 170 Silicone Fast Cure Elastomer.
U.S. Nuclear Regulatory Commission, Branch Technical Position, Auxiliary Power Conversion System Systems Dow Corning Corporation, Letter of July 21,1995, to Branch,9.5-1, " Guidelines for Fire Protection for NRC Document Control Desk, regarding an update on Nuclear Power Plants," May 1,1976.
i SYLGARD 170 Silicone Elastomer, SYLGARD 170 Silicone Fast Cure Elastomer, and DOW CORNING 96-U.S. Nuclear Regulatory Conunission, Branch Technical 081 RTV Adhesive / Sealant.
Position, Auxiliary Power Conversion System Systems Branch,9.5-1, Appendix A," Guidelines for Fire Factory Mutual Research Corporation, Factory Mutual Protection for Nuclear Power Plants Docketed Prior to System <fpproval Guide,1995.
July 1,1976," February 24,1977.
Institute of Electrical and Electronics Engineers Standard U.S. Nuclear Regulatory Commission, " Fire Protection 634," Standard Cable Penetration Fire Stop Qualification Program for Nuclear Power Plants Operating Prior to Test."
January 1,1979," FederalRegister, Vol. 45, No.105, May 29,1980, pp. 36082-36090.
International Organization for Standardi/ation, Intemational Standard 9002, " Quality Systems - Model U.S. Nuclear Regulatory Conunission, " Fire Protection for Quality Assurance in Production and Installation,"
Program for Operating Nuclear Pow er Plants," Federal First Edition, 1978-03-15.
Register, Vol. 45, No. 225, November 19,1980,pp.
76602-76616.
National Fire Protection Association. Fire Protection l
IIandbook, Fifteenth Edition, September 1981.
U.S. Nuclear Regulatory Commission, Generic I etter l
(GL) 86-10, " Implementation of Fire Protection l
National Fire Protection Association, Fire Protection Requirements," April 24,1986.
//andbook, Seventeenth Edition, July 1991.
I U.S. Nuclear Regulatory Cormnission. SECY-95-034, National Fire Protection Association, Standard 251,
" Status of the Recommendations Resulting From the
" Standard Methods of Fire Tests of Building Reassessment of the NRC Fire Protection Program,"
Construction and Materials."
February 13,1995.
25 NUREG-1552 E
. _ =
I Bibliography U.S. Nuclear Regulatory Commission, Information U.S. Nuclear Regulatory Conunission, Inspection Notice (IN) 88-04, " Inadequate Qualification and Report No. 50-286/95-10, inspection of Indian Point 3 Documentation of Fire Barrier Penetration Seals,"
Nuclear Power Plant, July 26,1995. Inspection February 5,1988.
conducted May 23-26, and June 19-20,1995.
i U.S. Nuclear Regulatory Commission, lufonnation U.S. Nuclear Regulatory Commission, inspection Report
)
Notice (IN) 88-04, Supplement 1, " Inadequate No. 50-317/318 94-15, Inspection of Calvert Clifts Qualification and Documentation of Fire Barrier Nuclear Power Plant, May 6,1994. Inspection conducted Penetration Seals," August 9,1988.
April 4-8,1994.
U.S. Nuclear Regulatory Conunission, Infonnation U.S. Nuclear Regulatory Commission, Inspection Report i
Notice (IN) 88 56," Potential Problems With Silicone No. 50-317/318 96-201, inspection of Calvert Cliffs j
Foam Fire Barrier Penetration Seals," August 4,1988.
Nuclear Power Plant, May 6,1996. Inspection conducted February 13 - February 15,1996.
U.S. Nuclear Regulatory Commission, Information l
Notice (IN) 94 28, " Potential Problems With Fire Barrier U.S. Nuclear Regulatory Commission, Inspection Report Penetration Seals," April 4,1988.
No. 50-361/362 94-01, Inspection of San Onofre, January 28,1994. Inspection conducted i
U.S. Nuclear Regulatory Commission, Inspection January 10-14,1994.
i.
Manual, inspection Procedure 64704, " Fire Protection Program," March 18,1994.
U.S. Nuclear Regulatory Commission, Inspection Report No. 50-387/388 95-14, Inspection of Susquehanna Steam U.S. Nuclear Regulatory Commission, Inspection and Electric Station, July 31,1995. Inspection conducted Enforcement Manual, Inspection Procedure 64100, June 5-9,1995.
"Postfire Safe Shutdown Emergency Lighting and Oil Collection Capability at Operating and Near-Term U.S. Nuclear Regulatory Comeission, Inspection Report Operating Reactor Facilities," March 16,1987.
No. 50-387/388 96-201, inspection of Susquehanna Steam Electric Station, Aptd 15,1996. Inspection U.S. Nuclear Regulatory Commission, Inspection and conducted January 30 - February 1,1996.
Enforcement Manual, Inspection Procedure 64150,
" Triennial Posttire Safe Shutdown Capability U.S. Nuclear Regulatory Commission, Inspection i
Reverification," March 16,1987.
Report No. 50-397/94 08. Inspection of Washington i
Nuclear Project 2, Febmary 25,1994. Inspection U.S. Nuclear Regulatory Conunission, Inspection Report conducted January 31 - February 4,1994.
No. 50-213/95-09, inspection ofIladdam Neck Power 4
Plant, June 19,1995. Inspection conducted April U.S. Nuclear Regulatory Conunission, inspection Report 10-14,1995.
No. 50-397/94-28, Inspection of Washington Nuclear Project 2, November 9,1994. Inspection conducted U.S. Nuclear Regulatory Conunission, Inspection September 26 - October 7,1994.
Report No. 50-219/95-11, inspection of Oyster Creek Nuclear Generating Station, July 21,1995. Inspection U.S. Nuclear Regulatory Commission, inspection Report conducted May 22 - June 25,1995.
No. 50-397/95-18, Inspection of Washington Nuclear Project 2, June 29,1995. Inspection conducted U.S. Nuclear Regulatory Commission, Inspection Report May 15-19,1995.
No. 50-244/94-14 Inspection of R.E. Ginna Nuclear J
Plant, June 13,1994. Inspection conducted U.S. Nuclear Regulatory Conunission, inspection Report May 9-13,1994.
No. 50-397/95-201, Washington Nuclear Project 2 i
Integrated Assessment Team Inspection,
{
U.S. Nuclear Regulatory Commission, Inspection Report October 3,1995. Inspection conducted No. 50-275/323 94-01, Inspection of Diablo Canyon August 7-17,1995.
Units I and 2, March 15,1994. Inspection conducted hauary 31 - February 10,1994.
U.S. Nuclear Regulatory Commission, Inspection Report No. 50-458/95-01, Inspection of River Bend Station, U.S. Nuclear Regulatory Conunission, inspection Report March 8,1995. Inspection conducted January 1 -
No. 50-275/323 95-03, inspection of Diablo Canyon February 11,1995.
Units I and 2, May 1,1995. Inspection conducted March 27-31,1995.
NUREG-1552 26
Bibliography U.S. Nuclear Regulatory Commission, inspection Report U.S. Nuclear Regulatory Commission, NUREG-0847, No. 50-458/95-02, inspection of River Bend Station.
" Safety Evaluation Report Related to the Operation of May 3,1995. Inspection conducted February 12 -
Watts Bar Nuclear Plant, Units 1 and 2," Supplements 18 March 25,1995.
and 19.
U.S. Nuclear Regulatory Commission, inspection Report U.S. Nuclear Regulatory Commission," Proceedings, No. 50-458/95-17, inspection of River Bend Station, NRC Regulatory Information Conference," April 9-10, June 9,1995. Inspection conducted April 10-14,1995.
1996.
U.S. Nuclear Regulatory Conunission, inspection Report U.S. Nuclear Regulatory Commission, Memorandum of No. 99901020/87-01, inspection of Brand Industrial February 27,1993, from Ashok C. Thadani, NRR, to Services, incorporated (BISCO) and V.C. Summer Timmas E. Murley, NRR, " Report on the Reassessment Nuclear Station, May 22,1987. Inspection conducted of the NRC Fire Protection Program."
January 20-23,1987, and February 25-27,1987.
U.S. Naclear Regulatory Commission, Title 10 of the U.S. Nuclear Regulatory Commission, inspection Report Code offederalRegidations, Part 21, " Reporting of No. 99901020/95-01, inspection of Brand Fire Defects and Noncompliance."
Protection Services, February 6,1996. Inspection conducted November 6-9,1995.
U.S. Nuclear Regulatory Conunission, Title 10 of the Code ofFederalRegulations, Part 50, General Design U.S. Nuclear Regulatory Commission, inspection Report Criterion 3, " Fire protection."
No. 99901284/95-01, inspection of Dow Corning Corporation, May 31,1995. Inspection conducted U.S. Nuclear Regulatory Conunission, Title 10 of the March 21-24, April 3-5, and April 18-21,1995.
Code offederalRegulations, Part 50, Section 50.48,
" Fire protection."
U.S. Nuclear Regulatory Conunission, inspection Report No. 99901292/95-01, inspection of Promatec U.S. Nuclear Regulatory Cornmission, Title 10 of the incorporated, April 8,1996. Inspection conducted Code offederalRegulations, Part 50, Appendix R," Fire December 6-8,1995.
Protection Program for Nuclear Power Facilities Operating Prior to January 1,1979."
U.S. Nuclear Regulatory Commission, Memorandum of October 7,1994, from Amarjit Singh, Plant Systems Vermont Yankee Nuclear Power Corporation, Letter of Branch, to Conrad E. Neuacken, Chief, Plant Systems January 15,1993, to NRC Document Control Desk, Branch, " Trip Report, Fire Barrier Penetration Seal submitting Licensee Event Report 93-001: " Degraded Audit, Waterford 3 Nuclear Power Plant."
Vital Fire Barriers."
j 1
U.S. Nuclear Regulatory Commission, Memorandum of Vermont Yankee Nuclear Pow er Corporation, Letter of November 23,1994, from Amarjit Singh, Plant Systems March 5,1993, to NRC Document Control Desk, Branch, to Conrad E. McCracken, Chief, Plant Systems submitting Licensee Event Report 93-001-01:
Branch," Trip Report, Fire Barrier Penetration Seal
" Degraded Vital Fire Barriers due to inadequate Audit Davis-Besse Nuclear Power Station."
documentation of assumptions and inadequate procedures."
U.S. Nuclear Regulatory Commission. Memorandum of February 9,1995, from Conrad E. McCracken NRR, to Vermont Yankee Nuclear Power Corporation, Letter of Gary M. Ilolahan, NRR, " Summary of January 31,1995 July 7,1993, to NRC Document Control Desk.
Meeting Concerning Products Manufactured by Dow submitting Licensee Event Report 93-00102:
Corning Corporation Used for the Construction of Fire
" Degraded Vital Fire Barriers Due to inadequate Barrier Penetration Seals."
Documentation of Assumptions and inadequate Procedures."
U.S. Nuclear Regulatory Commission, Memorandum of May 23,1995, from Charles E. Rossi, AEOD, to Wolf Creek Nuclear Operating Corporation, Letter of Gary M. Ilolahan, NRR,"AEOD Review of Fire Barrier February 6,1987, to NRC Document Control Desk, Penetration Seals (Fire Seals)."
submitting Licensee Event Report 87-001-00:
" Discovery of Breached Fire Barrier Seal."
U.S. Nuclear Regulatory Commission, Section 9.5-1,
" Fire Protection Program," of NUREG-0800, " Standard Wolf Creek Nuclear Operating Corporation, Letter of March 24,1987, to NRC Document Control Desk, Review Plan."
submitting Licensee Event Report 87-001-01:
" Discovery of Breached Fire Barrier Seal."
27 NUREG-1552 b
13ibliography l
Wolf Creek Nuclear Operating Corporation, i.etter of
" Technical S wilication Violation Inoperable Fire March 30,1988, to NRC Docurnent Control Desk, 13arriers Cau oy Personnel Errors."
rubmitting Licensee Event Report 87-001-02:
i l
l NUREG-1552 28
Appendix A Summaries of NRC Generic Communications Regarding Penetration Seals
%e NRC has issued a number of generic caught fire, and Davis-Besse where a penetration seal communications regarding fire barrier penetra' ion seals.
around a main steam line baked and pulled away from i
This included Generic Letter (GL) 86-10, the pipe.
" Implementation of Fire Protection Requirements " April 24,1986 (see Section 433 of technical assessment Information Notice 88-56 report), and four infonnation notices (ins). Summaries of the issues that were addressed in the information Infonnation Notice 88-56," Potential Problems With notices are presented below.
Silicone Foam Fire Barrier Penetration Seals," August 4, 1988,infonned licensees of the possibility that silicone Information Notice 88-04 foam penetration seals may contain nonconforming conditions such as splits, gaps, voids, and lack of fill.
Information Notice 88-04, " Inadequate Qualification and Specific example was the May 1987, Part 21 notilication Documentation of Fire Barrier Penetration Seals,"
by ll&B Promatec regarding nonconforming silicone Febnsary 5,1988, infonned licensees that some installed foam seals at Wolf Creek. The IN stated that the "NRC fire barrier penetration seal designs may not bc believes that if generic problems exist, then they may be adequately qualified for the design rating of the limited to only silicone foam fire barrier penetration penetrated fire barriers. The IN also indicated that seals but not to any pas ticelar vendor or installer."
deliciuncies included test qualification docmnentation being unavailable, incomplete, or inadequate. The IN Information Notice 94-28 also summarized existing staff guidance related to seals.
Information Notice 94-28, " Potential Problems With Fire information Notice 88-04, Supplement i Barrier Penetration Seals," April 5,1994, informed licensees of potential problems that could go undetected Infonnation Notice 88-04, Supplement 1, " inadequate as a result ofinadequate surveillance inspection Qualification and Documentation of Fire Barrier procedures and inadequate acceptance criteria. Plants Penetration Seals," August 9,1988, addressed specifically mentioned were Nine Mile Point, James A.
misapplication of silicone foam materials and resultant Fitzpatrick, and Vennont Yankee, w here nonconforming exposure of penetration seal materials to ambient or degraded conditions were discovered during licensee temperatures above design specifications. Specific inspections of penetration seals. The IN listed where examples of this included Diablo Canyon where seal NRC requirements and guidelines for fire barrier material in place around a diesel generator exhaust pipe penetrations could be found.
A-1 NUREG-1552
Appendix B Action Plan Summary Technical Assessment of Fire Barrier Penetration Seals
==
Description:==
Action plan for technical assessment of fire barrier penetration seals installed in nuclear pow er plants.
Background:
In 1988, the staff had completed an assessment of fire barrier penetration seats. Since 1992, the NRC received new reports of potential problems regarding seals. On the basis of the assessment it had completed in 1988, NRC inspections, and licensee event reports, the staff assumed that it would find plant-specilie deficiencies regarding documentation of fire tests, comparisons ofin-plant seals to fire tests, seals not installed where required, seals not installed or repaired properly, seals modified uithout a supporting engineering evaluation, and seals not inspected in accordance with plant surveillance procedures. The staffinitiated a technical assessment to j
determine if the actions it had taken in 1988 to address potential penetration seal problems had increased industry an areness of such problems, if there were any widespread or generic problems of safety significance, and if NRC requirements, review guidance, and inspection procedures for penetration seals are adequate.
Proposed Actions:
Inspect reactor and vendor penetration seal programs; observe fire endurance tests, review operating experience and previous NRC inspection results; assess the data and information obtained from the field uork and document reviews; identify commonality or correlation of evidence,if any, that suggests trends, widespread plant-specilie problems, or generic concerns of safety significance; detennine if NRC requirements, review guidance, and inspection procedures for penetration seals are adequate; and determine if existing industry (licensee and vendor) programs are adequate.
Regulatory Msessment:
Each reactor uses the defense-in-depth concept to achieve a high degree of fire safety.
Each reactor has an NRC-approved fire protection program that, if properly designed, implemented, and maintained, satisfies Section 50.48, " Fire protection," and General Design Criterion 3. " Fire protection," of Title 10 of the Code offederalRegidations Part 50. Therefore, each reactor has an adequate level of fire safety pending completion of the assessment.
B-1 NUREG-1552
1 l
Action Plan Summary
SUMMARY
TASK NOTES 1.
Identify types of seals in(talled in Sandia National Laboratories, i.etter Report of May 29,1992, from William nucbar power plants.
Lowrey, for NRC, "A Detennination of the Population of Fire Ilanier Types in Generating Stations "
2.
Identify and prioritize pote:9ial Materials.
technicalissues and problems.
Seal design and configuration.
Qualification tests.
Comparisons of tested to as-built.
Installation.
Surveillances and inspection.
Maintenance and repairs.
Configuration control.
Aging.
3.
Determine w hether or not there Obtain data from licensee event reports, NRC inspcetion reports, Part 21 are safety-significant problems database regarding reports of materials problems.
with penetration seal materials.
Conduct a vendor inspection of a materials marmfacturer. (Dow Corning Corporation was selected, in part, because (1) it is the principal manufacturer of the silicone-based penetration seal materials and (2) it had submitted Part 2 I reports.)
Conduet vendor inspections of seal installation vendors. (Brand and Promatec w cre selected, in part, because of the length of time in business, volume of business, and current activities.)
4.
Detennine w hether or not there Review results of previous NRC inspections of penetration seals.
are safety-significant problems regarding seal design, Observe fire endurance tests.
qualification tests, seal installation, seal surveillances and Review during vendor inspections and during new focused inspections at inspection, seal maintenance and representative sample of nuclear plants. Review reported concerns, if any; repairs, and configuration control.
gather information on qualified seals; and detennine if the seals were designed, tested, installed, inspected, and maintained in accordance with licensee j
commitments and NRC requirements.
Examine procurement documents, seal compatibility w ith barriers, lire j
cndurance tests associated u ith the seal qualitication designs, engineering evaluations, installer and inspector training programs, sample of installed seals.
quality control and quality assurance programs for installing and maintaining seals, deviations from NRC requirements, and sur.eillance requirements, and programs for technical speciliention seals.
Select seals for inspection based, for example, on seal type and material; seal location; seals that had been inspected, repaired or rew orked; and seals for w hich there w ere reports of specific concerns.
1 Select plants based on reports of problems (Davis-Ilesse, Waterford 3. and Susquehanna), old and new seal construction (Calvert Cliffs), significant rework by licensee after self-identification of problems (WNP2), and new construction including testing and engineering (Watts llar).
NUREG-1552 11-2
Action Plan Summary
SUMMARY
TASK NOTES 5.
Detennine whether or not there Review industry standards.
are concerns or problems regarding comparisons of tested Review NRC review guidance to as-built seal configurations.
Review industry practice during vendor and plant site inspections. Review in real time during Watts 13ar licensing.
4 6.
Identify and assess sundry Silicone foam formulation change.
I technical issues.
Dow Coming Part 21 reports.
Combustibility of silicone-based seal materials.
7.
Assess potential problems Sandia National Laboratories, i.etter Report of September 30,1994, from regarding seal aging.
Tina J. Tanaka, to NRC, " Aging of !> ire Barriers in Nuclear Power Plants."
8.
Assess the data and information obtained from the field work and document reviews; identify commonality or correlation of evidence, if any, that suggests trends, widespread problems, or generic concerns of safety
]
significance.
9.
Detennine if NRC requirements, review guidance, and inspection procedures for penetration seals are adequate.
- 10. Document results of technical Technical assessment report.
assessment with Peer review.
recommendations.
Independent management review panel.
NUREG-1552 report.
11-3 NUREG-1552
Appendix C Comparison ofIndustry Fire Endurance Test Standards Standard ASTM E-119 ASTM E-814 ANI4n6 UL 1479 IEEE 634 Title StandardTest Methods for Standard Test Method for Fire NELP A MAERP Standard Standard for Fire Tests of IEEE Standard Cable Fre Tests of Building Tests of Through-Penetration Men' :f Fire Tests of Cable Through-Penetration Fire Penetration Fire Stop Construction and Matenals Fire Stops and Prpe Penetration Fire Stops Qualification Test Stops NRC NUREG-0800, Standard information Notice 88-04 None None information Notice 8S-04 Re4rence Review Plan, Section 9 51 (1981)
Test
- 8. The test specimen shall be
- 7. Construction of the test fire 2 A.1 A wall or floor 41 Each representative 5 2.2 Selection of the sizes.
Specimen truly representative of the stops shall be of sufhcient size construction of previously construction type of through-construction, and matenals of Construction construction for which the and include aR conduits, pipes, proven fire resistance rating of penetration fires'op for which the cable penetration opening classification is desired, as to cables (jacket types, sizes.
at least 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> is to be used rat:ng is desired shall be fill to be used in the test shall materials, workmanship, and conductor types, percent fills) for the test. It may be modified tested. When a through-be representative of the cables details such as dimensions of required supports, ur other to a minimum acceptable size penetration firestop is used in the fire stop under 9
parts, and shall be built under through-penetrating items so as of 3' by 3' with the intended for use in both floor actualinstalled conditions It is conditions representative of to produce a truly representattve understanding that this mit and walls, each onentation is not the intent that differetd those obtaining as practically fire stop for which the evaluation result in approval by NEL.
to be tested unless it is construction types, that is, applied in butiding is desired PIA /MAERP for restricted size demonstrated that testing in instrumentation and medrum construction and operation.
applications in the field a single onentation does not voltage power cable, b6 The physical properties of the affect the test results.
instatted in the same test matenals and angredients 2.A 2 Size and configuration cable penetration unless this is indicat ve of actual conditions.
used in the test specimen of test penetrations to be as 4.2 Penetrating items are to i
shall be determined and shown in test standard be installed so that they recorded.
extend 12 21 inch from the exposed s:de, and 3611 inch from the unexposed side. The extended portions of the penetrating items on the unexposed side are to be supported by methods intended to be employed in field installation Time Temp ASTM E-119 ASTM E-119 ASTM E-119 ASTM E-119 ASTM E-119 Curve ZC h.
9 c:n
Z O
C h
Standard ASTM E-119 ASTM E-814 ANI 4/76' UL 1479 IEEE 634 r
G Temperature 17.1.3 Transmession of heat 10 2.1 A fire stop shat be C 2 No individual For a T rating-Foreword - The maximum
=
i y
Acceptance through the wall or partition considered as meeting the thermocouple of the allowable temperature e
Creena dunng the 6re endurance test requirements for the T rating unexposed surface of the fire 7.1 A througf>-penetration selected for a cable
]
shall not have been such as when it remams in the dunng stop shall exceed 325 'F Brestop shan remain in the penetraton fire stop should be
- c. '
to raise the temperature on the fire test. wittun the following above ambient conditions.
opening dunng the 6re based on the self-ignaion L
Rs unexposed surface more kmdations:
test, and shall comply with temperature of the outer cable 30 i
than 250 *F above as mitial the followog:
covenng the fire stop matenals E
temperature 10 2.1.1 The transmission of in contact with the cable p
heat through the fire stops A. The transmtsson of heat penetration fke stop, E
6 4 Where the conditons of dunng the rating penod shaB through the sampie dunng
,whichever has the lower self-w-
e acceptance place a hmdaten have not been such as to raise the ratmg penod shat not ignition temperature. For cable on the nse of temperature of the temperature of any raise the temperature penetrabon fire stops the self-the unexposed surface, the thermocouple on the unexposed measured by any ignition temperatures of the temperature end point of the surface of the fire stop or on any thermocouple on the outer cable covenng and fire l
fire endurance penod shall be penetrating item more than 325 unexposed surface of the fire stop matenal are generally determmed by the average of "F above as mshal temperature.
stop or on any penetrating above 700 *F. The maximum the measurements taken at Also the fire stops shat have tem more than 325 *F allowable temperature is the individual ponts; except that withstood the passage of flame above its initial temperature.
actual measured temperature if a temperature nse 30% in through openmgs, or the on the unexposed side and not excess of the specified hmet occurrence of flaming on any the temperature nse.
occurs at any one of these element of the unexposed side points, the remander shall be of the 6re stops.
6.12 Transmission of heat ignored and the Sre through the cable penetraton endurance penod judged as fire stop shalt not raise the n
ended temperature on is unexposed h
surface above the self-igndion temperature as determined in ANSI K65111-1971 of the outer cable covenng, the cable penetraton fire stop material, or matenalin contact with the cable penetraten fire stop etc i
k
Standard ASTM E-fl9 ASTM E-814 ANI4n6 L4.1479 IEEE 634 -
Flame Cntena 17.1.1 The wat or partiton 101.1 A fire stop shall be C.1 Fire shaR not propagate For an F rating-6.1 The test can be shat have withstood the considered as meeting the to the unexposed side of the considered acceptable and the endurance test without requirements for an F rating test assembly nor shall any 6.1 Athrough-penetration cable penetration fire stop passage of flame or gases when it remains m the opening visible flarnog be observed.
firestop shall remam m the sudable for use in accordance hot enough to ignite cotton durmg the flre test and hose opening dunng the fire test with the fire rating provided the waste, for a penod equal to stream test within the following and hose stream test and following is met:
that for which classsfication is hmitations:
shau comply with the desired following.
61.1 The cable penetration 10.1.2 The fire stops shall have fire stop shall have withstood withstood the fire test for the A. The sample shall
.the fire endurance test as rating penod without permitting withstand the fire test for the specified without passage of the passage of flame through rating period without the flame or gases hot enough to openmgs, or the occurrence of passage of flame through ignite the cable or other fire flammg on any element of the openogs, or the occurrence stop matenal on the unexposed side of the fire stops.
of flaming on any element of unexposed side for a penod the unexposed side of the equal to the required rating 4
10 t.3 Dunng the hose stream sample.
test, the fire stop shall not develop any opening that would B. The sample shall not permit a projection of water from develop any opening dunng the stream beyond the the hose stream test that unexposed side.
would permit a projection of water from the stream 10 2.1 A fire stop shall be beyond the unexposed side.
considered as meeting the g'
requirements for the T rating For a T rating:
when d remains in the dunng the fire test and hose stream A....the sample shall test within the following withstand the fire test dunng hmatations:
the ratmg penod without permitting the passage of 10.2.1.2...the fire stops shall flame through operungs, or have withstood me fire test the occurrence of flaming on dunng the rating penod without any element of the permitting the passage of flame unexposed side of the through the openings, of sample.
unexposed side of the fire stops.
B. See B above 10 212 See 1013 above f"':
2 5
- 4..
a
?
2C
~
9 s.
1 e
O 5
5 y
Standard ASTM E-119 ASTM E-814 ANI 4/76 UL 1479 IEEE 634 Ther nocouple Outs.de Fumace Outside Fumace Outside Fumace Outside Fumace w
Locations Thermocouple iocatens not 6 2 Temperature readings As specified in test standard, specified, However, 414 Temperature 5.3.10 Temperatu es on the i
shaR be taken at not less
" Temperature Measurement ANLMAERP Standard Fire measurements are to be penetration cold side surfaces 7
than 9 ponts on the surface Locatsons" Endurance Test Method to made by thermocouples shat be measured with E
[ war, floor,etc] Five of these Qualify A Protective Envelorg placed ca the unexposed thermocouples. A mornum of 3
shat be srTrnetricaPy inside Fumace for Class 1E Electncal Circuits side of the test sample and three thermocouples shan be Ei disposed, one to be..at the states in Section 3.4 4 5 test assembly.
located on the surface of each E.
center of the specimen, and 6 2M Minernum of three "Thermocouples shan be fire stop under test The 4
four at..the center of its thermocouple with not fewer located strategcally on the Inside Fumace
. maximum temperature on the quarter sections. The other than five thermocouples per 100 surface and at one foot face of the cabie penetration four shat be located at the ft'of floor surface and not fewer mtervals in the cable system 4 9 A mmimum of three fire stop shaR be measured.
descretion of the testog than noe thermocouples per and temperatures recorded thermocouples are to be As a minimum, temperatures authonty to oNam 100 ft* of wall specimen surface throughout the test
- used, and there are to be no shat be measured at the cable representative information on fewer than five jacket, cable penetration, fire the performance of the thermocouples per 100 stop mterface, the interface construction under test. None square feet of floor surface, between the fire stop and of the thermocouples shat be and no fewer than noe through metalhc components, located nearer to the edges thermoccupies per 100 other than the insulated cable of ti.e test specimen than one square feet of war surface.
conductor, and on the surface and one-half times the The floor surface or waN of the fire stop material.
thickness of the construction, surface area is to be the or 12 in.
gross area of test-assembly inside Fumace and sample areas.
9 inside Fumace 5.3 7 The temperature fixed by A
the curve shall be deemed to 5.1 The ternperature fixed by be the average temperature the curve shaR be deemed to obtained from the reading of be the average temperature not less than three obtained from the reading of thermocouples symmetncally not less than nine disposed and distnbuted to thermocouples for a floor, show the temperature for each roof, war, or partsbon and not cable penetration fire stop.
less than eight Additional thermocouples shal thermoccupies for a structural be used as necessary, for column syrnmetncally larger test specimens s
drsposed and distnbuted to show the temperature near au parts of the sample, etc
l l
~
Standard ASTM E-119 ASTM E-814 ANI4n6 UL 1479 IEEE 634 Hose Streara 101 Where required by the 9 31 Subject a dupicate B Immediately following the 5.3 The stream is to be 5 3.12 A hose stream test Ten conditon of acceptance, specimen to a fire exposure test fire endurance test the fire delivered through 2% inch shall be conducted subject a duplicate specimen for a penod equal to one half of stops shall be subjected to a hose and discharged through immediately following the end to a fire exposure test for a that indicated as the resistance hose stream applied to the a National Standard playpipe of the fire endurance test and penod equal to one half of penod in the fire test, but not exposed surface for a penod of corresponding size removal,if necessary of the that indcated as the more than 60 minutes, 4alculated on the basis of 2%
equipped with a 1-1/8 inch test slab.
resistance penod in tne fire immediately after whch subject
' minutes for each 100 sq ft of discharge tip of the endurance test, but not for the specimen to the impact, exposed area The hose standard-taper, smooth bore For power generating stations more than one hour, erosson, and cooling effects of a stream shall comply with one pattem without a shoulder at including nuclear-generating immediately after whch hose stream as described in of the following procedures:
the onfice. The water stations, a 1% in. hose subrect the specimen to the Table 1: "Pressare and Duration pressure and duration of discharging through a nozzle impact, erosion and cooling
- Hose Stream Test? The
- 1. The stream shall be appicaten is to be as approved, for use on fires in effects of a hose stream stream is directed first at the delivered through a 1% inch specified in Table 51 electncal equipment producing directed first at the middle middle and then at all parts of nozzle set at a discharge
" Pressure and Duration -
a long-range narrow-angle (30-and then at all parts of the the exposed face, with changes angle of 30* with a nozzle Hose Stream Test?
90* set at 30* angle) high exposed face, changes in in direction being made slowly.
pressure of 75 psi and a velocity spray only shall be directon teing made slowty.
minimum discharge of 75 gpm used. The hose stream shall 9 3.2 The test sponsor may with the tip of the nozzle a be applied to the exposed 10 4 The stream shall be elect with the advice of the maximum cf 5 ft from the side The water pressure shall delivered through a 2% in.
testing body, to have the hose exposed face OR be 75 psi, calcutated, at the hose discharging through a stream test made on the base of the nczzle and National Standard playpipe of specimen subjected to the fire 2 The stream shall be minimum flow of 75 gal / min corresponding size equipped test and immediately following delivered through a 1% inch with a duration of application with a 1-1/8 in. discharge tip the fire test nozzle set at a discharge of 2% minutes per 100 ft* of f
of the standard-taper smooth-angle of 15' with a nozzle test slab a'
bor= pattem without shoulder 9 3 3 Deliver the stream pressure of 75 psi and a at the onfice. The water through a 2% in. hose and minimum discharge of 75 gpm pressure and duration of discharge through a National with the tip of the nozzle a appication shall be as Standard playptpe of maxirnum of 10 ft. from the desenbed in Table 1:
corresponding size equipped exposed face OR
" Conditions For Hose Stream with a 1-1/8 in. discharge tip of Test,"of the standard standard taper, smooth bore
- 3. The stream sha!! be pattem without a shoulder at the delivered through a 2% inch From Table 1:
onfice. The water pressure and National Standard playpipe duration of appbcation shall be equipped with 1. inch tip, For a desired resistance as specified in Table 1 (of the nozzle pressure of 30 psi, penod of greater than 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> standard).
located 20 feet from the and less than four hours, the exposed face pressure at the base of the nozzle is to be 30 psi with For acceptance-No opening g
2-1/2 minute duration for develops that permets a y
each 100 ft' exposed area projection of water beyond the is unexposed surface dunng the
]-
hose stream test 8m k
2:
n C
z h
5 a
E L
4
?
w
v--
._,a
._,,_g Z
2 C
g
---s f
m Standard ASTM E.119 ASTM E-814 ANI4n6 UL 1479 IEEE w4 4
"9 g-r G
Nozzle 10 5 The nozzle onfice shall 9 3 4 The nozzle onfice shall be See Hose Stream Test section 5 4 The nozzle onfice is to 5.3.12 The nozzle distance m
U Distance be 20 ft from the center of the 20 feet from the center of the above for Nozzle Distance be 20 feet from the center of shall be 10 ft from the center o
+
exposed surface of the test exposed surface of:he test specifications the exposed surface of the of the exposed surface of the q
specimen if the nozzle is so specimen if the nozzle is so test specimen if the nozzle is test specimen Q
located that when directed at located that when directed at so located that, when the center its axrs is normal the center, its axis is normal to dwected at the center, its D
to the surface of the test the surface of the test axis is normalto the surface specimen if otherwise specimen if otherwise located, of the test specanen. If located, its distance from the its distance from the center shall otherwise located, its 3.
center shall be less than 20 be less than 20 feet by an distance from the center is to feet by an amount equal to 1 amount equal to 1 foot for each be less than 20 feet by an foot for each 10* of deviation 10* of deviation from the amount equalto 1 foot for u
from the normal normal-each 10* of deviation from the normal t-nb i
+
Appendix D Acronyms and Abbreviations l
AEC Atomic Energy Commission AEOD Oflice for Analysis and Evaluation of Operational Data ANI American Nuclear insurers ANSI American National Standards institute APCS 13 Auxiliary Power Conversion Systems 13 ranch ASTM American Society for Testing and Materials BISCO Brand Industrial Services Company BTP Branch Technical Position CFR Code ofFederalRegidations i
CTL Construction Testing Laboratories FM Factory Mutual FPFI Fire Protection Functional Inspection GDC General Design Criteria GL generic letter IIDSE high-density silicone elastomer IEEE Institute of Electrical and Electronics Engineers IN information notice IP3 Indian Point 3 LER licensee event report LDSE low-density silicone elastomer NFPA National Fire Protection Association NMSS Office of Nuclear Material Safety and Safeguards j
NRC U.S. Nuclear Regulatory Commission NRR Oflice of Nuclear Reactor Regulation OPL Omega Point Laboratories PSTS penetration seal tracking system QA quality assurance QC quality control RBS River Bend Station SNL Sandia National Laboratories l
SRP Standard Review Plan TSI Thermal Science, Incorporated UL Underwriters Laboratories, Incorporated WBN Watts Bar Nuclear Power Plant WNP2 Washington Nuclear Project 2 D-l l
t
i I
1 Appendix E i
Technical Assessment of Fire Barrier Peneteration Seals in Nuclear Power Plants I
J 4
1 4
i I
?
pn RE%q
~
~
POLICY ISSUE (Information)
July 1, 1996 SECY-96-146 FOR:
The Comissioners fA05:
James M. Taylor Executive Director for Operations 1
SUBJECT:
TECHNICAL ASSESSMENT OF FIRE BARRIER PENETRATION SEALS IN NUCLEAR POWER PLANTS PURPOSE:
To inform the Comission that the U.S. Nuclear Regulatory Comission (NRC) staff has completed its technical assessment of nuclear power plant fire barrier penetration seals.
The staff documented its assessment in a report entitled: " Technical Assessment of Fire Barrier Penetration Seals in Nuclear Power Plants," June 14, 1996. A copy of the report is attached, l
BACKGROUND:
As part of fire protection defense in depth, nuclear power plants are divided into separate fire areas by fire-rated walls and fire-rated floor-ceiling assemblies.
These fire barriers offer reasonable assurance that a fire will not spread from one plant area to another.
Openings in these fire barriers, known as fire barrier penetrations, allow such items as cables, conduits, cable trays, pipes, and ducts to pass from one fire area to another.
Fire barrier penetration seals are installed to seal these openings and maintain the fire-resistive integrity of the fire barriers.
Penetration seals are not technically complex, nor are they unique to the nuclear industry.
In fact, they are universally accepted building components that are used in a variety of residential, comercial, and industrial buildings wherever fire-resistive separation is needed. The same penetration seal materials, fire test CONTACTS: Steven West, NRR NOTE:
TO BE RELEASED AT COMMISSION MEETING 30 15-1220 ON TUESDAY, JULY 9, 1996 Chris Bajwa, NRR 301-415-1237 E-1 NUREG-1552
Fire lhurier Penetration Seals The Commissioners standards, and installation techniques that are used by the nuclear industry are used in these other industries. A large body of fire test results and fire experience (non-nuclear) has proven the fire-resistive capabilities and effectiveness of penetration seals.
In about 1985, the staff had become aware of the possibility that some i
licensees may not have been complying with NRC requirements and guidance for fire barrier penetration seals.
In response to these concerns, in 1987 and 1988, the NRC staff assessed fire barrier penetration seals. This assessment involved reviewing relevant data such as licensee event reports, inspection findings, and fire test reports; interviewing industry staff; inspecting licensees and vendors; and reviewing a sample population of as-built fire barrier penetration seal installations and the substantiating documentation.
Although it did not find safety-significant generic issues, the staff identified potential problems.
These included, for example, incomplete test documentation and improper seal installation techniques.
The staff addressed the potential problems in a series of information notices that it issued in 1988.
Since 1992, similar potential problems have again been reported.
In response, the Office of Nuclear Reactor Regulation (NRR) conducted a second technical assessment of fire barrier penetration seals.
The principal purposes of the second assessment were to address the potential problems, to determine if there were any problems of safety significance or with generic implications, and to determine if NRC regulatory requirements, review guidance, and inspection procedures for penetration seals were adequate.
DISCUSSION:
In support of its second technical assessment of penetration seals, the staff inspected reactor and vendor facilities; witnessed fire endurance tests of penetration seals; reviewed operating experience and previous NRC inspection and assessment results; and assessed the data and information obtained from the field work and document reviews.
The staff found several minor weaknesses with some of the plant-specific penetration seal programs that it reviewed.
These included, for example, inadequate documentation of seal installer training and failure to mark in-plant seals with their seal identification numbers.
The staff also found several potential weaknesses with the NRC fire protection inspection and review guidance.
These potential weaknesses, which were also minor, included:
(1) the NRC fire protection guidance documents do not reflect the current National Fire Protection Association (NFPA) position on fire testing laboratories; (2) there is no technical basis for the noncombustibility criterion for penetration seal materials that is specified in the NRC fire l
protection regulation and review guidance; (3) there is no staff guidance for comparing fire-tested penetration seal configurations to as-built configurations. (See recommendations below.)
Neither the plant-specific nor the programmatic weaknesses caused concerns that the penetration seals installed in the plants would not accomplish their fire protection function.
NUIEGl552 E-2 l
_ _ ~ - _ _ _ _ -
l' ire Harrier Penetration Seals The Commissioners On the basis of its review and assessment of available information, including the " Report on the Reassessment of the NRC Fire Protection Program" that had been conducted by NRR, the review of fire barrier penetration seals that had been conducted by the Office for Analysis and Evaluation of Operational Data (AE00), reports that had been prepared by Sandia National Laboratories on the population of fire barrier types installed in nuclear power plants and penetration seal aging, and the other documents referenced in its assessment report, the staff concluded that the penetration seal programs in industry remain satisfactory.
The staff found neither plant-specific problems nor generic problems of safety significance.
The staff expects that plant-specific deficiencies will occasionally be found during future licensee surveillances and NRC inspections.
However, licensees know what potential fire barrier penetration seal problems to look for during surveillance inspections; industry consensus fire test standards are available and are followed; and fire test results and qualified fire-resistant-seal materials and designs are available.
Therefore, licensees have the means to correct problems as they are found, and staff oversight will continue to ensure corrections on a case-by-case basis.
In addition, the multiple layers of protection provided by the fire protection defense in depth concept provide reasonable assurance that penetration seal deficiencies will not present an i
l undue risk to public he;1th and safety.
Finally, the staff concluded that I
actions it had taken in 1988 to address potential penetration seal problems increased industry awareness of such problems and resul.ted in more thorough surveillances, maintenance, and corrective actions. These actions together with continued licensee. upkeep of existing penetration seal programs and continued NRC inspections are adequate to maintain public health and safety.
On the basis of the results of its second technical assessment the staff will:
(1) revise the NRC fire protection guidance documents to reflect the current National Fire Protection Association position on testing laboratories; i
(2) delete the noncombustibility criterion for penetration seal materials from the NRC fire protection regulation and review guidance; (3) develop guidance for comparing fire-tested penetration seal configurations to as-built l
configurations; and (4) issue an Information Notice that summarizes this l
Commission paper and states that the attached technical assessment is available in the public document room.
i The Fire Protection Engineering Section of NRR conducted the technical assessment documented in the report.
The Special Inspection Branch of NRR and Brookhaven National Laboratory helped with the reactor and vendor inspections.
i Staff of NRR, AE00, the Office of Nuclear Material Safety and Safeguards (leiSS), Region I, Region II, Region III, and Region IV conducted a peer review of the assessment report. An Independent Management Review Panel that was j
l chaired by NRR and represented by NMSS and the Office of Nuclear Regulatory l
Research conducted a final review of'this report.
l The staff of the Fire Protection Engineering Section made presentations on i
fire barrier penetration seals and this assessment at the International
)
Conference on Fire Protection and Prevention in Nuclear Facilities, Barcelona, E-3 NUREG-1552
~
i Fire Barrier Penetration Seals The Commissioners Spain (December 5-7, 1994); the Nuclear Energy Institute Fire Protection Forum, St. Petersburg, Florida (January 29, 1996); and NRC Regulatory Information Conferences (May 1994 and April 1996). On March 7, 1996, the staff of the Fire Protection Engineering Section presented the results of this technical assessment to the Advisory Committee on Reactor Safeguards, Fire Protection Subcommittee.
The technical assessment report addresses concerns identified in outstanding penetration seal allegations.
The staff will use the assessment report as the basis to close these allegations.
The staff will also provide copies of the assessment report to cognizant technical staff.
This completes the staff actions on its technical assessment of nuclear power plant fire barrier penetration seal programs.
sf
_W
~
es M. Ta or xecutive Director for Operations
Attachment:
As stated DISTRIBUTION:
Commissioners OGC OCAA OIG OPA OCA ACRS ASLBP REGIONS EDO SECY l
NUREG-1552 E-4 b
NRC FORM 335 U.S. NUCLEAR REGULATORY CoMMisslON
- 1. REPORT NuM8ER (2-89)
(Assigned by NRC, Add Vol., Supp., Rev.,
NRCM 1102, and Addendum Numbers. If any )
32oi. 22o2 BIBLIOGRAPHIC DATA SHEET (See estruchons on the reverse)
- 2. TirLE AND SuBrlTLE NUREG-1552 Fire Barrier Penetration Seals in Nuclear Power Plants 3.
DATE REPORT PuBLISFED
' MONTH YEAR
_. July. _ _ _.
1996_.__
4 FIN OR GRANT NUMBER 5 AUTHOR (S) 6 TYPE OF REPORT C.S. Bajwa and K.S. West Technical
- 7. PERIOD COVERED (inctusve Dates) 8 PERFORMING ORGANIZATION - NAME AND ADDRESS (it NRC. provee Dwson, omce or Reg,on. u S Nuceear Regulatory Commesson. and mahng address. itcontractor, I
prowne name and mahng address )
Division of Systems Safety Analysis j
Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission l
Wishington, DC 20555-0001
- 9. SPONSORING ORGANil.ATION. NAME AND ADoRESs (it NRC, type Same as acove*, itcontractor, peowde NRC owson, omce or Regon, u S NucJear Regulatory Com/msson.
6nd meeng address )
S:me as above
- 10. SUPPLEMENTARY NOTES
- 11. ABSTRACT (200 mords orless)
Nuclear power plants are divided into separate fire areas by fire-rated structural barriers. Fire-rated penetration seals are installed to seal certain openings in these barriers. The seals maintain the fire-resistive integrity of the barriers and provide reasonable assurance that a fire will be confined to the area in which it started. The U.S. Nuclear Regulatory Commission conducted a comprehensive technical assessment of penetration seals to address reports of potential problems, to determine if there were any problems of safety significance, and to determine if NRC requirements, review guidance, and inspection procedures are adequate. The staff did not find plant-specific problems of safety significance or concerns with genenc Implications. The staff concluded that the general condition of penetration seal programs in industry is satisfactory. The staff tiro concluded that actions it had taken in 1988 and 1994 to address potential penetration seal problems increased industry awareness of such problems and resulted in more thorough surveillances, maintenance, and cc,rective actions. These previous staff actions, together with continued licensee upkeep of existing penetration seal programs and continued NRC inspections, are adequate to maintain public health and safety.
j
- 12. KEY'
'DS/DEScRIPTORS (bst words or phrases tnat we assst researchers a locanng the reporf )
13 AvAiLAaiuIY Si A1EMLNI unlimited F
mier Penetration Seals Silicone Foam 14 SECURITY CLASSIFICATION Fire Barriers (Th,s vage)~
unclassified (TnIs Reportl ~
unclassified 15 NUMBER OF PAGES 16 PRICE NRC F OHM 335 (2 49)
Th s form was electroncally produced by Ehte Federal Forms Inc
i i
A i
)
i i
1 1
i i
Printed on recycled paper i
i i
I, Federal Recycling Program
NUREG-1552 FIRE BARRIER PENETRATION SEALS IN NUCLEAR POWER PLANTS JULY 1996 1,
UNITED STATES g;-h551 y5,1 FIRST CLASS Mall I"c-d[C-Ncy
- I I # I 1 f< ; a L 2 NUCLEAtt REGULATORY COMMISSION Dfv POSTAGE AND FEES PAlO
,'t.
[#
um WASHINGTON, DC 20555-0001 09 (brwic'N'mrq L I ^ 4 7 cs,
PERMfT NO. G47
" f r o
,,4,7 S yc -
OFFICIAL BUSINESS PENALTY FOR PfWATE USE $300
'C
. - -