ML19351D710
| ML19351D710 | |
| Person / Time | |
|---|---|
| Site: | Oconee, Mcguire, McGuire, 07002623  |
| Issue date: | 10/06/1980 |
| From: | Jeffrey Riley CAROLINA ENVIRONMENTAL STUDY GROUP |
| To: | Atomic Safety and Licensing Board Panel |
| References | |
| NUDOCS 8010140587 | |
| Download: ML19351D710 (12) | |
Text
.
\\
/
0
+
\\
/<
UNITED STATES OF AMERICA 4%%mt3 g
NUCLEAR REGULATORY COMMISSION usupe OCT.
BEFORE THE ATOMIC SAFETY AND LICENSING BOAR N>
Y2
$ g [b. %
D.ne In the Matter of
)
N,34mm j
)
DUKE POWER COMPANY
)
'Ns/ g 9
)
(Amendmcat to Materials License
)
Docket No. 70-2623 SNM-1773 for Oconee Nuclear Station
)
g}; ()c' h jgy;j Spent Fuel Transportation and
)
Storage at McGuire Nuclear Station )
)
CESG'S MOTION TO REOPEN RECORD The evidentiary hearing in this matter closed April 29, 1960 Preposed findings of fact and conclusions of law have been submitted by the parties.
A safety related matter bearing on the conclusion as to whether a criticality incident may occur in the McGuire spent fuel pool is reported in the most recent issue of POWER REACTOR EVENTS.
As the-licensee involved in the reported event is the Applicant in this proceeding, and as the event is directly relevant to testimony and to 4he findings of fact, CESG respectfully requests this Board to reopen the record.
CESG would be satisfied to have the record include the event as described foregoing and Applicant's letter referred to therein.
- However, CESG would have no objection to receiving further testimony in a reopened proceeding if the Applicant so requests._.,
"UnplannedBoronDilution"isthetitl[of'aniteminPOWER REACTOR EVEUTS-United States Nuclear Regulatory Commission, Vol. 2, No. k/ July 1980, p. ll.(Attachment 1).
A degineralizer was supplying water to the low pressure injection system at 800 ppm boron.
The initial reactor coolant system boron in Oconee Unit 2 was reduced from 1895 ppm to 1539 ppm boron before the problem was detect,ed n..
and corrective measures taken.
- 1-
'e os QSoS B101014005 5#/
I
2nyd,WAE ~
,. y' r.
m-o v:.
--. *f '
... p... 'is '
~
The Board, interested in pursuing the question of possible
)
T criticality in a cask drop incident, admitted a revision to CESG's contention 2 (CESG's Proposed Elem.ents of Fact, etc., May 28, 1960,
- p. 12).
CESG showed that a cask falling from the far edge of the i
cask pi-t (case 3) had Sufficient energy to gyrate over the wall separating the pit from the fuel pool and onto whatever fuel might be placed in racks in that part of the fuel pool.
A collapse of the racks would permit fuel assemblies to approach sufficiently i
close that criticality would become a consideration.
If the fuel pool boration were maintained sufficiently high, criticality would not occur.
However the k,ff 's of various fuels, McGuire first core, Oconee spent fuel, etc., were such that a sufficiently large reduction in boron concentration would, under the circumstances, 4
permit criticality.
Clearly, one factor in the avoidance of an accidental criticality incident is the maintenance of the fuel pool boron level above a specific minimum requirement.
Applicant and Staff are in essential agreement in regard to k
values cf 0.92 for McGuire spent fuel (Applicant's Proposed p
Findings, Etc., May 19, 1960, L60)(LRC Staff Proposed Findings, Etc.,
June 17, 1960, tl39) and for Oconee spent fuel of 0.95 (Applicant Exhibit 33 at pp. 5-6).
Applicant and Staff are also in agreement that a decrease in boron concentration of 100 ppm would increase k,ff 1% (Applicant ibid. S61, NRC Staff Exhibit 40).
If the lattice structure of the fuel pins is maintained, with corresponding k,ff's ranging from 0.92 to 0.96 (Staff ibid. L;6.2), boron concen-tration reductions of as little as'200 ppm, and no more than 600 ppm, could result in criticality.
~%
_ _ _. The testimony in this proceeding developed a number of factors which would determine whether criticality could occur in the dropping of a fuel cask onto assembly containing racks in the fuel pool.
Criticality is the condition in which the flux of fission generated neutrons neither increases nor decreases.
It is represented by k,ff equal to 1.0000.
The initial technical specification for McGuire called for a fuel pool k,77 of 0.91 (F3AR 5 12.2) in unbarated water.
k,7f increases with the con.
centration of U-235 and of Pu-239 in the fuel; with decreasing the distance between fuel assemblies; with decreasing the boron concentration in the pool water.
k is decreased by the eff material present in the racks; by defects in the uniformity of the lattice structure of the fuel pins; and by the presence of poison pins in the assembly.
Intervenor contended that in the event that a cask feli en assembly containing racks in the. fuel pool that the assemblies would be brought clos ~er together as a consequence of crushing the rack structure, that in part the lattice gecmetry woula be retained, that there was a likelihood of a reduced pool boron concentration (the present technical specification calls for 2000 ppm of boren),
and that criticality could occur.
In response the ERC Staff relied on an administrative control to prevent the cask from reaching a position frc:r.hich it could topple into the fuel pool (NRC Proposed Findings of Fact, Etc.,
June 17, 1980, t169).
Such reliance is not sufficient.
"The
[TMI Lessons Learnedj Task Force concluded that the need for improved operations reliability is the most important lesson learned from the accident at TMI-2."
(NUREG-0376, July, 1979, p. 12)
-k-As to the continuing effectiveness of an administrative control, the requirements have existed, but the implementation has been unsatisfactory."
(ibid. p. 14)
The additional fact of the Applicant's noncompliances (CESG Exhibit 2) indicates that the Staff's. dependence on administrative control is misplaced.
In the absence of an appropopriate physical barrier, and given the unresolved differences in the record as to whether the cask could topple into the fuel pool, it is conserative to proceed on the basis that it could.
The Staff testified that a cask d: op would aff ect 76 assemblies (NRC Findings, 5156).
Applicant testifies that a drop of the cask in an axis vertical position would affect 63 assemblies.
A drop with the axis horizontal would affect 226 (Tr. 5062-k).
This final tes timony repudiates Applicant 's earlier testimony tnat a cask drop would cause local deformation only, at the top of the rack (Tr. kh27, 11. *-11).
Applicant 's cas' drop witness agreed with Intervenor that beyond the zone of impact of the cask with the racks, racks would be brought close together without distortion of the fuel pin lattice (Tr. 3065-6).
It seems conservative to conclude that, in the event of a cask drop, some assemblies would be brought close together without suffering lattice distortion.
The consequence 1
1 would be an increase in k eff' 1
Soth Applicant and Staff maintained that it was unlikely that the pool boron concentration would fall below the technical spec-ification level of 2000 ppm.
"It's really hard to get bcron out of that pool water." (Tr. k963)
Staff's witness estimated tha-
-7
-d the probability of criticality was 10 to 10 (Tr. 49c7).
This i
~.... _ _. _
"l'
- )
- was less emphatic than testimony a half year earlier, before the Board Order of October 31, 1979, seeking more quantitative analyses in the areas of criticality.
At that time it was testified that nothing could make the assemblies go critical, "They would be far suberitjeal."
(Tr. khk2)
Although, at that time, another Staff witness in cross examination stated, Well, we tried to prevent the spent pool be (sic) critical by preventing the cask going over into the spent fuel pool.
That's only way to crevent scent fuel beinc danaced and become (sic) critical. (Tr. a2cO.
Empnasis supplied.)
Applicant's witness testified that in the years which Oconee has operated that the concentration of boron in the fuel pool had never fallen below 2000 ppm (Tr. 5081-2).
Both Staff and Applicant testified that the only way for the fuel pool boron to be reduced in concentration was by dilution.
They stated that volume of water in the fuel pool decreases due to evaporation, but the boron remains with the result that the_ concentration increases.
Makeup water restores the boron co.ncentration to normal.
Alarns are present in the fuel pool "which would alert the operators to any significant reduction in boron concentration."
(NRC Findings, t16k)
However these alarms are fuel pool level alarms and provide information about boron concentration only by inference (Tr. 5084).
This testimony was given on April 29, 1980.
On May 7, 1980, just nine days after Applicant testified that there "was not a mechanism for removing large quantities of water from the pool [vis-avis $Iakeup with unborated water]--the boron stays behind" (Tr. 5077), and "So there's no way of removing boron from the pool without removing the water.
.", and "You would have to dilute some way with unborated water" (Tr. 508k),
/
Applicant experienced a reduction in the boron concentration in Oconee-2 reactor coolant system to 1539 ppm.
At this time it was being supplied with water at 800 ppm boron, although it was mistak-enly. thought that the boron level was more than 1000 ppm higher.
Boron was removed from coolant water by a deionizer that had not been properly conditioned.
Fuel pool water is continuously cooled, filtered and treated i n a deionizer.
The rate of circulation is 310 gal / min through an 80 ft3 deionizer containing h0 ft' of Amberlite 1RN-277 or equivalent mixed bed ion exchange resin (FSAR Table 9.1 3-1,e).
This fuel pool demineralizer, if not properly conditioned to yield a 2000 ppm boron outflow, will remove boron from the fuel pool.
Can such an improperly conditioned deionizer bring the fuel pool level down to the critical region of 1500 ppm?
There is no evidence in the record in this regard.
Applicant testified to daily analyses of fuel pool b6ron during refueling (Tr. Sc95).
This does not provide sufficient assurance because, in the May 7th incident, the sampling technique was defective ( Attach. 1,
- p. 12) and had led to misleadingly high bcron values; further the chemistry records had not been updated.
It has also been testified that the fuel pool water volume is about 400,000 gal and that of the containment at refueling 350,000 gal (Tr. 5093).
The fuel pool is circulated at a rate of 2000 gal / min or greater (FSAR Table 9.1 3-1, a).
Any dilution of fuel pool boron from admixture with boron deficient containment side water will soon be experienced throughout the pool.
The event of May 7 illuminates concerns expressed by the Board in a colloquy in regard to the likelihood of a criticality
2
-7_
s incident:
" Highly unlikely.
Is it fair for me to translate that as also saying, not impossible?"
"Well, I guess so, but highly unlikely.
It's close but you're probably right."
"These gentlemen haven't done a calculation which guarantees something."
"That's right.
We haven't proven it."
Tr. E987-8)
In view of the foregoing fact, CESG urges this Board to reopen the evidentiary record to, minimally, include Attachment 1 from Power Reactor Events.
CESG would also urge the Board to take i
official notice of NUREG-0576, sections 2.2.1, p. 12, and 2.2 3, l
- p. Ih, which present Staff conclusions as to the reliability of I
operations.
If, in the opinion of this Board, corrective actions are required in the cask drop matter, a reopened evidentiary hearing concerned with the efficacy of the proposed remedy would i
i seem to be apposite.
i hespectfully submitted, 7
Abi{ Y Y Jesse L. Riley, Prd2ident Carolina Environmental Study Group At. Charlotte, N. C.
October 6, 1980 I
I a
( -
,y.
Attacnment i y
1 30W._ R
,R _.:
R
_: :N__S g
t
. /
United States Nuclear Regulatory Commission 3
Vol. 2, No. 4/ July 1980' This cocument is a bi. monthly summary of sel~ted events that have cccurred at nuclear power plants.
Tnese events have been taken from public information sources, namely Licensee Event Reports and NRC inspection Reports, and are or have been under review by the NRC. They are considered infor-mative to persons interested n the nuclear industry and may concern safety related matters,,such as cersonnel errors and gcuipment malfunctions. Although most summaries are published shortly after ne events have occurred. i, is sometimes necessary to publish otners several months later. This nfay ce cue. for instance. to generic problems noticeable only after an extenced period of time, or because of lengtny re",olution of certai.1 concerns. All events are reported in the belief that open coimmunica-tion benefit' all parties.
200;'.".TD g\\
L*S?:Pc
~
9 "C
- [ Of[:: c!the g' 8 Tg,
g TABLE OF CONTENTS if em N
u\\
" Loss of RCP Cooling and Natural Circulation Cooldown".................
1
" Safety injection on Loss of Vital Bus"...............................
5
" Decay Heat Removal System inoperability"............................
7 "Structu ral Defect in Auxiliary Building"..............................
9
" Unplanned Boron Dilution"....................
11
" Broken Fuel Assembly Holddown Sr rings".................
12 "Cor. trol Element Assembly Malfu nctions".............................
14
" Co n c e n ser Le a k a g e" I..............................................
16 References Editor: Sher"i A. Massaro Office of Management and Program Analysis U. S. Nuclear Regulatory Commission
- :or the May-June 1980 Period Wasnington. DC 20555
^
{
E UNPLANNED BORON DILUTION At Oconee Unit 2* on May 7, 1980, the spare debora' ting demineralizer was started up for chloride removal from-the low pressure injection (LPI)
The reactor was in cold shutdown, and the reactor coolant system.7 system (RCS) was partially drained for reactor coolant pump traintenance.
Tne demineralizer was first run for 10 minutes to allcw a chemistry Chemistry records indicated that the demineralizer sample to be taken.
was boron-saturated to about the same concentration as the LPI system (1895 ppm), and the chemistry sample taken showed a demineralizer outlet concentration of 1884 ppm.
The demineralizer was returned to service following the sample result, The demineralizer was promptly f
and two more chemistry samples were taken.
bypassed and isolated when the last evaluation showed an LPI The RCS deboration from 1895 to 1539 ppm left a margin of of 800 ppm.
295 ppm above that necessary to maintain the 1% Ak/k shutdown margin In addition, given the required by Ocenee's technical specifications.
initial boron concentration of 1895 ppm, and assuming an RCS volume at approximatley 30,000 galions, a new demineralizer would become saturated at about 1400 ppm, which is still above the concentration for a 1% Ak/k j
- An 887 MWe PWR located 30 miles, west of Greenville, South Carolira.
, :q It is probable that the sampl' ng technique did not take into account the potential for higher concentrations in the sample line, which should have been flushed before samples were taken.
Also, the chemistry records which Indicated that the deborating demineralizer was boron-saturated apparently had not te:
- pdated, and did not pros 'de up-to-the-minute i
The end result was an unpionned positive reactivity boron concentration <.
insertion during cold shutdown.
As stated, the immediate corrective action was to bypass and 'solate the ceborating demineralizer. Makeup to the RCS was also initiated to restore its original co-cation. Administrative controls were implemented concerning updating of t ecc.Js and prevention of demineralizer use whi?e i
the RCS is in a drained-down condition. Since the source range alarm would provide an early warning in the unlikely event of unplanned criticality,
)
a req;irement for checking the alarm's operability once per shift was l
This shift check will be added to the procedure for deemed adequate.
instrument surveillance during shutdown.
l 4
1 i
7 Duke Power company, oconee 2, Docket :;o.30-270, LER co-03, June 3, 1960.
i l
j r
l 4
i
-~
~
=mm-
UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION BEFORE THE ATOMIC SAFETY AND LICENSING BOARD In the Matter of
)
)
I'G DUKE POWER COMPANY
)-
Docket No 70-262 D
)
(Amendment to Materials
)
~"" "-
T, License SNM-1773 for Oconee
)
Usc-Nuclear Station Spent Fuel
)
9
- 3 Jg g y q._.
Transportation and Storage at
)
Difi:
00dsgr:;an:8 cf t'e se McGuire Nuclear Station) q c r: --
/
AFF1RFAriuN OF SERVICE 4
I v-u 1 affirm that copies of "CESG's Motion to Reopen Record" in tn above-captioned matter have been served on the ro11owing by deposit in the United States mail this 6th day or October, 1960:
Marshall E. Miller, Chairman
- Edward G.
Ketchen, Esq.
Atomic Safety and Licensing Counsel for NRC Adgulatory Eoard Staff U.S.
I;uclear Regulatory Office of the Executive Commission Legal Director Washington, D.C.
20555 U.S.
Nuclear Regulatory Commission Dr. Emmeth A.
Luebke Washington, D.C.
20555 Atomic Safety and Licensing Board William L.
Porter, Esc.
U.S.
Nuclear Regulatory Associate General Counsel Cc= mission Duke Pcwe. Company Washington, D.C.
20555 Port Office Box 2178 Charlatte, North Carolina 28242 Dr. Cadet H. Hand, Jr.
Director Chairman Bodega Marine Laboratory Atomic Safety and Licensing of California Board Panel Post Office Box 247 U.S.
Nuclear Regulatory Bodega Bay, California 94923 Commission Washington, D.C.
20555 J. Michael McGarry, 111, Esq.
Debevoise and Liberman David S. Fleischaker, Esq.
Natural Resources Defence Council 1200 Seventeenth Street, N. W.
1735 Eye Street, N.W.
Washington, D.C.
20036 Suite 709 Washington, D.C.
20006
2-Chairman, Atomic Safety Chase R.
Stephens and Licensing Appeal Board Docketing and Service U.S. Nuclear Regulatory Section Cornission Office of the Secretary Washington, D.C.
20555 U.S.
Nuclear Reg; 2r.ory Ccemission Washington, D.C.
20555 9
[esseL.Riley h
9 r