ML19345G434
| ML19345G434 | |
| Person / Time | |
|---|---|
| Issue date: | 10/22/1980 |
| From: | Bender M Advisory Committee on Reactor Safeguards |
| To: | Ahearne J NRC COMMISSION (OCM) |
| Shared Package | |
| ML19295E769 | List: |
| References | |
| FOIA-81-80, FRN-45FR76603, RULE-PR-50 NUDOCS 8104070242 | |
| Download: ML19345G434 (4) | |
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NUCLEAR REGULATORY COMMISSION g[,., g W
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- j ADVISORY COMMITTEE ON REACTOR SAFEGUARDS WASHING TON. D. C. 20555 Oh @"Ef..
October 22, 1980 Y1.'wr I2?.=..
Honorable John F. Ahearne Chairman U. S. Nuclear Regulatory Commission
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Washington, D. C.
20555
Dear Chairman Ahearne:
Thank you for the opportunity on October 16 to participate in the discussion of the proposed rulemaking concerning fire protection.
I believe that it was the first time than an ACRS member was privileged to participa+ 3 as an 3s individual in the rulemaking process. Nevertheless, I found myself frustrated by the style of the meeting and the lack of any frame of reference for discussion. The Commissioners may have been adequately conversant with fire protection practice in nuclear power plants, but when I recall the garbled nature of the presentation, it is difficult to believe that anyone present at
..e the meeting could have really understood what the NRC staff was using as the Ese basis for its recommendations.
.s I want to emphasize a few points:
1.
The basis for Appendix R and the requirements of tne Branch Technical Position (BTP 9.5-1) is not adequately set forth in the regulator
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criteria. No one challenges the need for fire protection. Where circumstances permit, the use of separation by wide distance, three-
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hour fire resistant barriers, automatic sprinklers, and manual fire
.K 1 fighting capability may all be of value. The overall need is to s5mi provide good fire protection in existing plants, but the crucial need is to reduce the probability of fire initiation and the orooogation
"=Eit of small fires into large ones.
Initiation is avoided by using non-Ei.....
combustible materials, avoiding electrical short circuits, preventing T
EH combustible lubricants from contacting hot surfaces, and limiting fire initiating activities such as welding, testing with burning candles MMf and electri. cal arcing to circumstances where there is a full fire 5
watch, standby fire fighting equipment and temporarily installed 7
protective barriers. The NRC rules should emohasize these controls
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over other reouirements. The " burn to extinction" principle rather than suppression should be the public safety basis wherever possible and especially in new designs.
If fires can be extinguished, fine,
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but public safety should not be highly dependent on this capability.
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The pos.ibility is adtr.itted that combustible materials will occasionally s... <
be brought into the plant from outside, including solvents, wood scaffolding, cleaning rags and even mattresses. NRC needs to emphasize
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r, Honorable John F. Ahearne October 22, 1980
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housekeeping and inspection practices to limit the potential for s==
such fire hazards. This is especially important during plant shut-
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downs, plant revisions, and when new construction is proceeding EE ".
concurrently with plant operations. Pre-evaluation of fire
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initiators and potential combustibles when nonoperational work is 3.g..
underway should be especially emphasized.
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A fundamental safety principle should be to shutdown the reactor _
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when a fire occurs, no matter what its size, in order to minimize
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the amount of eouioment and facilities imoortant to public safety
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that might be vulnerable to fire damage. This principle is essen-
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tially ignored in the rules.
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Fire protection inside containment is hardly covered by the rule, p 7...~"
but combustibility levels are low and lubrication systems, the main is =:-
sources of combustibility, have been examined under PTB 9.5-1.
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However, the distribution of hydrogen igniters, which must be tested f# ~
periodically, throughout the containment violates the princip'e of S"#.t eliminating fire initiators.
I am thus uncomfortable with their use
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e,ven if they could reliably prevent containment uverpressure due to
_5 hydrogen combustion.
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4.
The use of fire retardant coatings is an excellent fire protection i2 9
provision that will be most effective in eliminating fire initiators.
They won't and were never expected to be effective against r.eally hot or _ deep-seated fires. They are intended to prevent small fires from spreading and they have been shown to work.
If they did not is.=i interfere with inspection and maintenance access, I would want to
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extend their use in preference to sprinklers and caseous fire F~
suppressants. The staffs concern with controllino the scread of hot k~~
fires by suporession devices is misolaced emchasis.
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- 5. ' Alternate shutdown capability is certainly a desirable feature for F E+
fire contingencies and other reasons, but it is not the primary P'"!
public safety need to offset inability to limit the spread of hot
. _V fires. Prompt shutdown on detection will satisfy virtually all of i:a= =.
the shutdown capability needs that would be offset by the fire l7"-
protection of fire resistant barriers, sprinklers or other fire con-
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-trol measures. Fire detection is not fully reliable but neither are sprinklers, barriers and manual fire fighting features. All depend E_
major alterations in the control circuitry of ooerating olants.
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upon detection reliability. There is reason to be concerned about The safety risk in making such alterations because of inadvertent
- q installation errors has public safety imoortance that can offset much
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of the anticipated public safety improvement.
Furthermore, if the plant is shut down, only e few safety areas would be vulnerable.
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Honorable John F. Ahearne October 22, 1980 Es-coolant systems could be deoressurized and external fire water EEE supolies brought in to protide cooling water makeuo to the core,
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serious consequences of a fire micht be neoligible from a oublic mJ,_;
safety standpoint. Why isn't this acoroach being considered,
?Qif especially for new designs?
6.
Total fire protection response is a basic public safety issue.
The proposed rule places so much emphasis on the five-man fire
[i brigade that one would believe this level of manpower will assure adequate fire fighting capability.
It will only be a minor improvement over a three-man brigade.
Basically, it provides u.23 for two hose operators and two fetch-and-carry helpers who are
- j;;;T directed by a chief firefighter. That was enough personnel to fight the fire at Brown's Ferry, but that level of manpower wasn't
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needed for a long time, and by the time it was naeded, the whole ET ke regional fire fighting capability wa et the site but wasn't used.
The emphasis should be on the total fire fighting resource needed.
When there is a very limited outside resource, the plant may need Ec;,
its own fire department or full capability to follow application
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of the " burn to extinction" principle foilowing promot shutdown.
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The work load on the staff and the hearing process will not be diminished by the rulemaking. The proposed rule as presented will mainly prescribe requirements for water mains, fire barrier alternatives, size of the fire N
brigades, battery capacity, and some administrative measures. For most of 4
these matters, exceptions will be required to tiie proposed rule because the physical-circumstances do not permit rigorous conformance in most of the cases DJ "=
not yet settled. The route for establishing how exceptions are admitted is not
'i, clear to anyone.
If, as the legal staff implies, the process is the same as
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that for challenging an order, then nothing will result from the existence
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The ACRS has recommended against the proposed rule because it is excessively ese prescriptive and inconsistent with other regulatory practices.
I oppose it
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on those grounds, too, but my real-concern is that the imalementation of the rule is adverse-to public safety because:
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It places too much emphasis on controlling consequences of a large hot fire and not enough on the initiation and spread of small fires
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where the fire risk really should be controlled.
2.
It does not put sufficient emphasis on shutting down the reactor when a fire occurs, no matter what its scale, even though early T
shutdown will obviate concern with most associated circuits and will
.f limit the portions of the plant that really need protection.
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3.
It does not address adequately the emergency response capabilities needed to fight a significant fire.that exceeds fire brigade capabilities including the availability of external fire fighting and supplemental core cooling provisions.
144.r ae paa
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Honorable John F. Ahearne October 22, 1980 4.
The extensive physical modifications to plant structures, water
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systems and shutdown controls if broadly implemented introduce
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the risk of engineering and construction errors that may be more
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of a public safety risk than the large hot fires that are postulated to require supplemental-fire protection.
r I urge the Commission to reexamine the problem in its broader aspects and avoid amplifying the narrow concerns of fire protection specialists beyond their appropriate consideration in public safety nuclear risk control.
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'Thank you again for giving me an opportunity to state my personal views on these matters.
av ii.=ii Sincerely,
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-M. Bender
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MB/cw NE cc:. R..F. Fraley
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