[ RadSafe ] Risk Communication

Sat May 11 16:25:17 CDT 2013

beyond design basis accident?
why don't design beyond that basis?

On Sat, May 11, 2013 at 4:42 AM, Jaro Franta <jaro_10kbq at videotron.ca>wrote:

> Thanks,
>
> The Canadian PARs units are installed in Candu stations and some LWR
> stations overseas.
>
> PAR units are installed in nuclear plants in:
> Canada
> Finland
> France
> Korea
> Ukraine
>
> I don't know what size the IP-2 PARS units are, but a typical Candu station
> requires close to thirty PARs, which are boxes roughly two feet square each
> (like an oversize ashtray).
>
> As new self-start threshold  2% H2 with available oxygen
> Operating range  1% to ~8% hydrogen
> Capacity increases about linearly with hydrogen concentration
> Capacity increases with pressure
>
> http://enertechlibrary.cwfc.com/libdocs/literature/1307.pdf
>
>
>  Jaro
> ^^^^^^^^^^^^^^^^^^^^^^^^^
>
>
>
>
> -----Original Message-----
> From: radsafe-bounces at health.phys.iit.edu
> [mailto:radsafe-bounces at health.phys.iit.edu] On Behalf Of Steve Schulin
> Sent: May-11-13 4:08 AM
> To: The International Radiation Protection (Health Physics) Mailing List
> Subject: Re: [ RadSafe ] Risk Communication
>
> Hi Jaro - Well, I see that USNRC's draft "Director's Decision", issued last
> month, denies the NRDC petition, but not because NRC disagrees that the
> PARS
> at Indian Point-2 (with its two installed PARS units) would be an ignition
> hazard in some severe accidents. NRC staff has concluded that the benefits
> of PARS in coping with design basis accidents -- station blackout in
> particular -- outweighs the risks added in the case of beyond design basis
> accidents, because severe accidents are so unlikely.
>
> Your message seemed to point to beyond design basis accident at Fukushima
> as
> rationale for PARS. I appreciate your comments and your knowledge of how
> Chalk River analyzed PARS. Was it the isotope production reactor there that
> you were working on? If you didn't have to install thirty-to-sixty IP-2
> sized PARS units (each one is capable of handling several grams of hydrogen
> per second), then you were dealing with less maximum hydrogen than the big
> US LWRs. NRDC says the two PARS units at IP-2 are sufficient for
> design-basis accidents. And NRC does not contest that they would be
> overwhelmed in more severe accidents, in which hydrogen production is
> projected to be as much as 10 kilograms/sec.
>
> The draft DD is available via NRC's ADAMS document ACN ML130501596
> http://www.nuclear.com/archive/2013/04/02/ML130501596.pdf
>
> Very truly yours,
>
> NUCLEAR.COM
>
> Steve Schulin, Founding Editor
> http://www.nuclear.com
> info at nuclear.com
> 301-433-4211
>
> http://www.linkedin.com/in/nuclearcom
> http://twitter.com/nuclearcom
> http://facebook.com/nuclearcom
>
> On May 10, 2013, at 7:28 PM, Jaro Franta wrote:
>
> > Hi Steve,
> >
> > You don't seriously believe *any* of the BS spread by the Natural
> > Resources Defense Council ?
> >
> > Having been involved in preparing licensing-related documentation for
> > PARs installation in Canada, I would like to share some basic
> > information that I reviewed & used in my documents, referenced from
> > numerous development & test reports written by the folks who developed
> > the Canadian version of PARs, in Chalk River Nuclear Laboratories.
> >
> > First of all, PARs can NOT increase the likelihood of a hydrogen
> > explosion in a beyond design basis accident, because they self-start
> > at a hydrogen concentration that is well below that required for an
> explosion.
> > Once PARs self-start, they have a high capacity for hydrogen
> > recombination, which heats them up to roughly the same temperature as a
> barbecue.
> >
> > A plant-specific analysis is prepared by the licensee for the
> > regulator, to indicate how many PARs need to be installed, and in
> > which specific locations, to ensure that adequate recombination
> > capacity is available under all circumstances.
> >
> > Secondly, US NPPs already have electric-powered hydrogen "igniters".
> > The problem with those is not that they will blow up the pant, but
> > that they don't work in a total station blackout situation, like
> Fukushima.
> >
> > Regarding the issue of containment vent filter clogging, sure, a
> > poorly designed filter can clog.
> > A similar issue arose in past years regarding containment cooling
> > water
> > recirculation: New pump intake filters had to be designed, built and
> > installed at nuclear plants, to ensure that even under the worst
> > conceivable circumstances adequate water could be circulated from the
> > containment sump, to maintain cooling.
> >
> > Ignoring appropriate solutions is simply another way of saying
> > dragging your feet.....
> >
> > Jaro
> > ^^^^^^^^^^^^^^^^^^^^^^^^^
> >
> >
> >
> >
> > -----Original Message-----
> > From: radsafe-bounces at health.phys.iit.edu
> > [mailto:radsafe-bounces at health.phys.iit.edu] On Behalf Of Steve
> > Schulin
> > Sent: May-10-13 6:43 PM
> > To: The International Radiation Protection (Health Physics) Mailing
> > List
> > Subject: Re: [ RadSafe ] Risk Communication
> >
> > Hi Jaro, and all. One reason I don't support use of PARS is because
> > such devices can actually increase the likelihood of a hydrogen
> > explosion in a beyond design basis accident. See "passive
> > autocatalytic recombiners could act as hydrogen igniters in beyond
> > design basis accident" at
> > http://news.nuclear.com/blog7.php/indian-point-2-passive-autocatalytic
> >
> > I'm also not so keen to put filters on the hardened vents. The safety
> > function of the vents is so important that it seems unwise to risk
> > clogging up the vent path. I'm no engineer, but as a radiation
> > protection technician, and as a homeowner, it it has been my
> > experience that filters clog.This concern about filter-clogging was
> > raised in at least one of the post-Fukushima ACRS meetings (NRC's
> > Advisory Committee on Reactor
> > Safeguards) where the filtered vent issue was discussed, but I haven't
> > noticed any studies or reports on the subject.
> >
> > As to contributors to public outrage, I'd rank several items as of
> > much greater significance than the explosions. The admission by TEPCO
> > that they purposefully did not improve tsunami protection to guard
> > against increased max credible tsunami height is one example. That the
> > reasoning included not wanting to alarm the public was an especially
> > egregious aspect of this, and I see this raised in many more recent
> newspaper pieces than the explosions.
> >
> > Very truly yours,
> >
> > NUCLEAR.COM
> >
> > Steve Schulin, Founding Editor
> > http://www.nuclear.com
> > info at nuclear.com
> > 301-433-4211
> >
> > http://www.linkedin.com/in/nuclearcom
> > http://twitter.com/nuclearcom
> > http://facebook.com/nuclearcom
> >
> >
> > On May 10, 2013, at 5:36 PM, Jaro Franta wrote:
> >
> >> Thanks for the link.
> >>
> >> It seems to me that a very big part of the "Outrage" following
> >> Fukushima came from the public seeing images of one reactor after
> >> another
> > blowing up.
> >>
> >> Does anyone dispute that assertion ?
> >>
> >> Anyway, a fairly easy and relatively inexpensive way to combat that
> >> specific outrage is to make sure that NPPs subject to total station
> >> blackout do not blow up, because of hydrogen accumulation.
> >> Now why on earth is the US nuclear industry dragging its feet on
> >> installation of Passive Autocatalytic hydrogen Recombiners (PARs),
> >> while everyone else around the world is installing them, is totally
> >> beyond
> > me.
> >>
> >> Similarly for containment venting filters.
> >>
> >> How about some leadership for a change ?
> >>
> >>
> >> Jaro Franta
> >> ^^^^^^^^^^^^^^^^^^^^^^^^^^^
>
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