ML20210N558
| ML20210N558 | |
| Person / Time | |
|---|---|
| Issue date: | 07/05/1994 |
| From: | Mccraken C NRC (Affiliation Not Assigned) |
| To: | AFFILIATION NOT ASSIGNED |
| Shared Package | |
| ML20210N260 | List: |
| References | |
| FOIA-97-180 NUDOCS 9708250362 | |
| Download: ML20210N558 (2) | |
Text
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- B 5 '! NUCLEAR REGULATORY COMMISSION ky.....,/ wAswiwotos, o.c. nosss-oooi July 5, 1994 .
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e Dear Mr.
SUBJECT:
CONCERNS REGARDING THE APPLICATION OF SILICONE FIRE BARRIER PENETRATION SEALS IN NUCLEAR POWER PLANTS On April 18, 1994, during a phone conversation with Mr. Patrick H. Madden you expressed concerns regarding the application of silicone fire barrier penetration seals,. Our understanding of your concerns is as follows:
- 1. .During a presentation regarding engineering evaluations for penetration seals (made during the week of April ll,1994) Electric Power Research 4
Institute (EPRI) promoted performance-based fire modeling techniques for evaluating fire barrier penetrations in lieu of the prescriptive extrapolation of test result methods recommended by Generic Letter (GL) 86-10.
- 2. Fire barrier penetration seals in nuclear power plants may have the same problems as Thermo-Lag fire barriers in that the various fire barrier penetration seal configurations may not be bounded by fire tests.
With respect to item 1 above, Enclosure 1 to GL 86-10, " Imp 1 mentation of Fire Protection Requiremer.ts," Interpretation 4 " Fire Area Boundries," defines the term fire area as it is used in Appendix R to 10 CFR 50. The regulation does -
not require fire area boundries to be wall-to-wall or floor-to-floor barriers.
This interpretation defines a fire area as an area sufficiently bounded to withstand the fire hazards associated within the area and, as necessary, is capable of protecting important equipment within the area from a fire outside the area. Where fire area boundries are not bounded by wall-to-wall or floor-to-ceiling barriers with all penetrations sealed to the fire rating required of the boundary fire barrier, these unsealed opening (s) should not permit flame, radiant energy, smoke and hot gases to pass through the barrier.
Licensees having these conditions should assess the adeqe.cy of their fire area boundries to determine if they are capable of withstanding the fire This GL guidance is somewhat hazards associated with the fire area.
performance-based and would not prohibit the use of fire modeling approaches to evaluated the adequacy of fire barrier penetration seals or unprotected
-openings. Licensee evaluations of these conditions are required to be Our acceptance of these evaluations would maintained on site for NRC audit.
depend upon the quantity and nature of combustible material on either side of the barrier; the location of the penetration seal or opening; the location, vulnerability and importance of shutdown systems on either side of the <
barrier; and the mitigating fire protection features in the area.
9708250362 970814 #
PDR FOIA / l GUNTER97-180 PDR O
LIMITED DISTRIBUTION Mr.; ] Ey Q With respect to item 2 above, the Plant Systems Branch is currently evaluating the fire penetration seal programs at two plants. This program will focus on the design, installation, qualification testing, and the adequacy of supporting engineering evaluations justifying fire barrier penetration seal designs that deviate from tested configurations. From these two assessments, the staff expects that sufficient information will be obtained to make a determination regarding the generic adequacy of fire barrier penetration seals installed at nuclear power plants. After we have completed our on-site audits and evaluated the insights, we will advise you of our findings regarding the general application of penetration seals at nuclear power plants.
If you have any questions or if the above summary of your concerns is incorrect, please contact Mr. Patrick Madden at (301) 504-2854. Thank you for bringing these issues to our attention.
Sincerely, WWW Conrad E. McCracken, Chief Plant Systems Branch
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