ML19284A678
| ML19284A678 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 02/28/1979 |
| From: | Duflo M NRC ATOMIC SAFETY & LICENSING APPEAL PANEL (ASLAP) |
| To: | |
| References | |
| NUDOCS 7903150189 | |
| Download: ML19284A678 (13) | |
Text
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NRC PUBLIC EXCMT ROOM UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION g g ATOMIC SAFETY AND LICENSING APPEAL BOARD o
Yh Alan S. Rosenthal, Chairman jh
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- ',,.ep [8 Dr. John H. Buck Michael C. Farrar h
2 1979 e?.*> 7 s
SERVED oAA b
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In the Matter of
)
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VIRGINIA ELECTRIC AND POWER
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Docket Nos. 50-338 OL COMPANY
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50-339 OL
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(North Anna Nuclear Power
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Station, Units 1 and 2)
)
)
MEMORANDUM AND ORDER February 28, 1979 (ALAB-529)
Six months ago, after reviewing the record in this operating license proceeding involving the first two units of the North Anna facility, we reserved judgment on two safety issues which we had taken up on our own motion.
ALAB-491, 8 NRC 245 (August 25, 1978).
In virtually all other respects, we affirmed the Licensing Board's judgment --
which had not been challenged before us -- that there were no barriers to the staff's issuance of the requested oper-ating licenses.
O M'
_1/ We also had to keep open the radon-release issue which is pending in a number of cases.
See ALAB-491, supra, 8 NRC at 250, fn. 12, and Philadelphia Electric Co.
(Peach Bottom Units 2 and 3), ALAB-509, 8 NRC (December 1, 1978), and ALAB-512, 8 NRC (December 21, 1978).
. One of the pending safety issues concerned the ability of the plant to withstand damage from missiles generated either inside or outside the plant.
The other involved the settlement of the land under the pumphouse.
In both respects, we solicited and obtained over the course of these past months further information from the parties. 1'/
Having studied all the papers now before us, we find it necessary to explore both matters further at an evi-dentiary hearing before we can pass final judgment on the merits.
The concerns still remaining involve, principally, the areas which are set forth later in this opinion.
Although the parties should focus on those areas, their prepared testimony must be broader in scope.
For, while we already have before us a wealth of material on both issues, that material has come before us in somewhat informal fashion.
Moreover, particularly with respect to pumphouse settlement, the information is somewhat dis-jointed in the sense that it is necessary to locate and peruse a large number of varied documents to obtain a full picture of the problem and its proposed resolution.
In order to create a formal record which will lend itself to
--2/ In addition, the Union of Concerned Scientists sought and was granted leave to file briefs amicus curiae on the missile question.
The staff and applicant have duly responded to those briefs.
. ready review by higher tribunals, we request the parties to make their prepared testimony reasonably self-contained.
In other words, the prepared testimony should itself con-tain significant background information and references and be structured so that it can be understood with mini-mal reliance upon documents filed at earlier times.-3/
If that is done, then, at the conclusion of the upccming hearing, all the evidence necessary to understand and decide the issues will be found in 'the formal record made before us.
Having indicated how the testimony should be struc-tured, we turn now to an outline of our principal con-4 cerns.- /
These are the topics which should receive the parties' primary attention.
_3/ Of course, this is not meant to exclude the possibility that we and the parties may find it necessary to utilize those prior documents for other purposes, e.g.,
as a basis for testing the validity of positions taken at the hearing.
--4/ As in our prior order (see 8 NRC at 247, fn. 3), we do not recite in this opinion background information sufficient to allow anyone other than the parties (and those who have been following the proceeding closely) to understand fully the nature of the problems troubling us.
It is our intention, however, when we ultimately decide the pending issues, to write an opinion suffi-ciently comprehensive to be understood by the more casual observer.
_4_
A.
Missilec.
Based on what is now before us, the only troubling aspect of the missile question appears to involve the possibility of damage caused, not by objects originating outside the plant, but by pieces of the turbine breaking loose.
The staff has made preliminary calculations of the probability that unacceptable damage to a safety system will result from such a turbine missile.
These calcula-tions indicate that the probability of that occurring may be greater than the guideline the staff generally follows. 5[
The staff takes the view, however, that continued operation of the facility under existing conditions is justified in light of certain conservatisms inherent in its analysis.
In our judgment, greater elaboration and probing of the reasons underlying that opinion are needed before we can pass upon the validity of the staff position.
Against this background, the staff's testimony should address at least the following major areas.
_5/ To be specific, the staff estimates that the " upper limit probability for unacceptable damage by turbine missiles is about.2 x 10-5 per turbine year" (SER Supp.
No.
2, p. 10-2).
This is larger than the guideline of 10-7 provided in Regulatory Guide 1.115,
. (a)
The staff's elaboration of its analysis should be made as quantitative as possible.
Where appropriate, it can tell us of the possible imprecision of its estimates and provide an evaluation of the uncertainties associated with those estimates.
In other words, the staff should provide its best assessment of the magni-tude of each of the conservatisms it has identi-fied in its analysis.
In this connection, the staff should expand on the analysis provided in its submittal of January 5, 1979. 5/
(b)
The staff should describe how the relevant Task Action Plans are expected to lead to improvements in its estimates or modify the methodology used in its analyses.
In doing so, it can elaborate generally on its explanation of how the relevant Task Action Plans function in the regulatory process.
6 / See affidavit of Kazimieras A. Campe dated January 5, 2.979, attached to NRC Staff Response to UCS Supplemental
-~
Erief.
The staff should explain how its expanded analysis conforms to the Standard Review Plan sections referred to in this affidavit.
. (c)
The staff should tell us why it believes to be incorrect the applicant's lower estimate of the probability of turbine failure generating mis-siles which might impact on " class 1" safety components.
In furnishing its testimony on the turbine missile question, the applicant may wish to furnish its own views oa the above subjects.
B.
Pump House Settlement.
1.
Relationship to Public Safety.
Our study of the numerous documents relating to pump-house settlement has revealed very little that furnishes any perspective as to the potential seriousness of the problem from a safety standpoint.
In other words, the reports and analyses do not indicate what would happen if the subsidence of the land were to lead to a failure of the service water system.
As background, then, the parties should discuss the extent of the safety problem involved.
In doing so, they should tell us, inter alia, (a) what are the upper limits of functional requirements and system capabilities of the service water system (e.g.,
pump and pipe flow requirements and capacities) both during normal
. operation and under accident conditions; (b) which service water systems or components could fail as a result of further settlement; (c) where and how might they fail and what leak rates might be expected; (d) how such failures would be detected and what actions would be taken; and (e) how failure of the service water system affects other plant safety systems under ncrmal operation and accident conditions.
2.
Settlement History.
We have had difficulty in relating the various stages of construction activity to the timing and rate of the settlement that has taken place.
This stems from the fact that the records are fragmented over time and contained in various documents.
Because of this, it is also difficult to correlate the settlement of the pumphouse itself with the settiement of other significant portions of the service water system.
In order to aid our understanding, then, the parties should prepare two separate charts, one for the pumphouse and one for other relevant points (e.g.,
exposed pipe ends and any other monitoring points on the pipes), each showing the amount of settlement that has taken place with the passage of time.
In that regard, the span of time involved
. should be labelled not only by date but also in terms of the construction activities that were taking place at various points. 1!
3.
Soil Mechanics.
The parties should discuss their current understanding of the engineering properties of the soils underlying the pumphouse, the reservoir dikes and the service water lines.-8/
This discussion should include an indication of how their knowledge of this subject has developed in terms of the timing of the studies and investigations that have led to their current understanding.
4.
Dewatering.
The record reveals considerable dispute over the need for and long-term effectiveness of dewatering the soil under the pumphouse and the service water lines.
The
_7/ Including, especially, such foundation-related activ-ities as excavation and backfilling, building of the pumphouse, laying the service water lines between pumphouse and reactor buildings, dewatering for reactor or other major building construction, build-ing of the cooling pond and dikes, and dewatering of the ground under the pumphouse and service water lines.
_ / In this connection, we need to know precisely what 8
the term " secondary consolidation" is intended to mean.
, staff should: (a) provide the bases upon which its require-ments for groundwater control were developed, and (b) indi-cate, with appropriate supporting references, the safety factor normally required to protect against seismic-induced soil liquefaction.
5.
Monitoring.
It is not clear to us precisely how the extensive monitoring of the settlement of class I structures is con-ducted.
We should be provided with: (a) a description of the type of instruments and methods by which settlement of these structures are monitored, together with an evalu-ation of the accuracy of such monitoring; (b) information as to how the movements of buried service water pipes are monitored or estimated. SI '
9/ We are particularly interested in whether the "47' elbows" in the service water lines near the pumphouse have been monitored.
These appear to be within the area dewatered around the pumphouse; the staff should inform us whether, and if so how much, these elbows settled before and after dewatering.
. 6.
Stress Analysis.
The parties should cover the topic of stress analysis, so that we may learn what the impact of varying amounts of settlement will be.
In this regard, they should describe the types of loads assumed and methodology used in analyzing stress limits for service water piping, indi-cating whether stresses due to the apparently greater settlement of pipes relative to that of the pumphouse are included in the load analysis.
In addition, the staff should (a) provide a full justification for selecting the differential motion limit of 0.22 feet between corners of the north side of the pumphouse and the expansion joint, and explain how this satisfies the staff's concerns on stress limits in the flexible couplings (see staf f evalua-tion, pp. 5-6); (b) explain how limiting the absolute elevation of the exposed ends of the expansion joints to 0.22 feet (measured from August 3, 1978) satisfies the staff's concerns on stress limits in the buried pipes (see staff evaluation, pp. 7-8); and (c) with respect to all the established linits, set forth the basis for choosing 75% of the limit as the level which triggers the reporting requirement.
M
As may be seen, some of the information we have asked for is more readily available to one party than the other; in any event, some of our questions would be better addressed in the first instance by one rather than the other.
We leave it to the sound judgment of the applicant and the staff to determine which areas each should cover in its prepared testimony.1S/
Some areas need to be covered 10/ During the course of this proceeding, the North Anna Environmental Coalition -- which is not a party to the case -- has sent a number of letters either to the staff or to us, stating its position on and raising questions about the pumphouse settlement issue.
As the Board's Secretary recently informed the Coalition's spokesman, Mrs. June Allen, we are not permitted to consider such communications directly in passing on matters before us.
(See letter of January 11, 1979).
But, as a result of the action we are taking today, the parties will now be preparing written testimony covering the entire pumphouse settlement question.
In these circumstances, it will be convenient for them to insure that their testimony contains sufficient information to resolve the questions the Coalition has posed in its written communications.
Compare Iowa Electric Light & Power Company (Duane Arnold Energy Center), ALAB-108, 6 AEC 195, 196 fn. 4 (1973) (indi-cating that " limited appearance" statements made under 10 C.F.R. 2.715 can " alert the Board and the parties to areas in which evidence may need to be adduced")
and Public Service Electric & Gas Company (Hope Creek Units 1 and 2), ALAB-251, 8 AEC 993, 994 (1974) (where the parties were invited to comment on the concerns expressed by a non-party to the case).
Cur interest is in seeing to it that all legitimate concerns are dealt with in the course of the testimony; we leave to the parties the selection of the format for doing so.
In calling for responses in this general way in this instance, we are not expressing any judgment on the perceptiveness or significance of particular ques-tions the Coalition has posed; if the parties believe that certain questions are irrelevant or otherwise not deserving of a response on the merits, they may say so.
. by both; with respect to other topics, perhaps one can take principal or sole responsibility.
We offer the sug-gestion, however, that they confer to make sure that all subjects are covered properly.
Given the amount of study that the parties have already given the two issues remaining before us, it should be possible for both the applicant and staff to file their prepared testimony by April 6, 1979.11/
Within two weeks from the date of this order, any other party to the operating licensing proceeding who wishes to participate in the upcoming hearing must notify us of that fact and advise us of the nature and extent of its planned partici-pation.
Those who wish to do so will then be given the opportunity to file prepared testimony in response to that to be filed by the applicant and staff.
And, to the extent that either the applicant or staff wishes to respond on subjects which were within the other's principal responsi-bility (see the preceding paragraph), they will be given the chance to do so.
After all prepared testimony is in hand, we will confer with the active participants about scheduling the hearing.
11/ If this period proves insufficient, they will be free to seek an extension of time.
. It is so ORDERED.
FOR THE APPEAL BOARD 4A.cnAj/ b Margpet E.
Du Flo Secretary to the Appeal Board
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