ML20137D609

Discusses Foundation Problems at Site.Testimony Given During 1974 Show Cause Hearings Re Pervasive Fracturing,Remedial Drainage Problems,Temp Change Effects & Risk from Prolonged Rains Described

ML20137D609
Person / Time
Site:	North Anna, 05000000
Issue date:	07/11/1977
From:	Mueller R AFFILIATION NOT ASSIGNED
To:	Coufal F Atomic Safety and Licensing Board Panel
Shared Package
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References
FOIA-85-363 NUDOCS 8508220522
Download: ML20137D609 (2)

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A - R:uto 1, B:x 253 Staunton, Virginia July 11, 1977 Mr. Frederic Coufal Chairman

• Atomic Safety and Licensing Board U. S. Nuclear Regulatory Commission Washington, D. C. 20555 ,

Re: Foundation Problems at the North Anna Nuclear Station ,

Dear Mr. Coufal:

Since I was an expert witness at the "Show Cause" hearings of 1974, I have followed the tortured spectacle of North Anna. At this time, I feel compelled to bring to your attention the testimony given by me then as well as some additional points which, I believe, pose further difficulties for this power station. ,

Pervasive Fracturing At the Show Cause hearing, I stated that I observed 1

the foundation rocks at North Anna to be so fractured that the reactors would "be supported only by gravity and friction since the rock appears to have little large scale coherence." Subsequent events such as the numerous settling problems have, I believe. borne out the pertinence ,

of this testimony. '

Remedial Drainage Problems .

Although " remedial drainage" has been attempted as a solution to the groundwater problem, it is clear that

• any attempt to drain 'the rock either by active methods such as pumping or passive methods involving horizontal drains will lea'd to the same results: namely, loss of fine clay particles and eventual further settling.

.Similarly, the expansion couplings designed to avoid pipe rupture give no assurance that rupture will not oc- ,

cur when the designed expansion is taken up.

At this point, it should be emphasized also that fractured rock with clay or other fine porous fracture -

fillings, such as prevail at North Anna, is in many ways more subject to settling than homogeneous sediment since each clay-rock interface may be the locus of an erosion channel. .

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Temperature _ Chance _ Ef fects In 1974, I also warned of the consequences of dis-regarding the effects of change in the temperature regime on the coherence properties of the rocks and saprolite.

Of course, this problem has not surfaced yet since t rs it de-

' pends on the presence of warm water f rom the reac o and its mingling with the groundwater af ter start-up.

It is likely that settling problems will be multiplied at that time.  !

Risk from Prolonced Rains _

Given the behavior of the saprolite, I also wonder what would happen should the area be vissed by prolonged rains such as might accompany a. succession What of frontal will the flushing systems or tropical storms.

action of rapidly infiltrating waters do to the fine -

particles which have been disturbed or exposed by new channels?

It is unfortunate that the proceedings on North Anna have always had the foregone conclusion that these This attitude has reactors must be built at this spot.

resulted in the covering up of hazards ar.d biased testi-the State mony by the applicant, I fear agencies which seem to be continuing to ,this day.

the consequences for the public interest will be grave.

Sincerely yours, bxau-Robert F. Hueller, Ph. D.

RM/hs o 4 .

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