ML20206C517
| ML20206C517 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 11/10/1988 |
| From: | Gad R ROPES & GRAY, VERMONT YANKEE NUCLEAR POWER CORP. |
| To: | Atomic Safety and Licensing Board Panel |
| References | |
| CON-#488-7484 OLA, NUDOCS 8811160310 | |
| Download: ML20206C517 (12) | |
Text
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s FUed: November 10,1988[C(g[i[g USN"C UNITED STATES OF AMERICA
'88 iTR 14 P3 :08 NUCLEAR REGULATORY COMMISSION before the pn r:.
ATOMIC SAFETY AND LICENSING BOARD
)
In the Matter of
)
)
VERMONT YANKEE NUCLEAR )
Docket No. 50-271 DLA POWER CORPORATION
)
)
(Spent Fuel Pool (Vermont Yankee Nuclear
)
Expansion)
Powee Station)
)
)
MEMORANDUM OF VERMONT YANKEE NUCLEAR POWER CORPORATION IN RESPONSE TO MEMORANDUM AND ORDER OF 10/24/88 AND MOTION FOR LEAVE TO FILE THE SAME I.
Introduction.
After disposing cf the issue with which 'its ' Memorandum and Order (Sur,plemental Opinion Concerning Response to NECNP Interrogatory 5)"
(10/24/88) deals, the Board adds this observeion:
"In addition, the current lack of schedule for the enhanced fuel pool cooling system leaves in place for an indefinite time period the present alleged (and apparent) sfolation of the single failure criterion which seems to be occurring routinely, through reliance on the residual heat removal system every time there is a partial core offload. See Tr. 55-56, 59, 77-78 (first prehearing conf erence); ALAB-869,26 NRC 13,21, n.4 (1987).*
Memo and Order at 7 (emphasis added).
While the Board concludes that the ' apparent violation
- is 'beyond our authority to remedy in this proceeding (which is limited to consideration of the storage of more than 2004 fuel assemb!!es in the spent fuel pool)," /d.,
the Board's apparent pre-judgment of the merits of Contention I in this proceeding is not mere dictum, Prescindtng from its implication for the 8811160310 0011jo DR ADOCK O5000271 PDR
admission of the contention in the first place,1 this statement of the Board's predisposition is troubling for two reasons: First, the point in question is central to the defense of the proposed amendment.8 Second, the Board's conclusion is completely and demonstrably erroneous. For these reasons, and for the additional reason that Vermont Yankee is not content to leave the Board under the misimpression that it willingly violates the rules (or safe practice) with every refueling, Vermont Yankee respectfully moves for leave to submit the fellowing information to the Board.
II.
Factual Statessents.
A.
The existlag SFP cooling systess, even after a single active failure, has adequate cooling capacity to carry the heat load of the must critical case at both 2,000 and 2,870 assemblies in the SFP.
In order to determine the sufficiency of a spent fuel pool cooling system, one has to know three parameters: (i) the heat carrying capacity of the cooling system (in its various modes, if more than one is possible), (ii) the heat load imposed by discharged spent fuel assemblies at relevant times after shutdown of the nuclear reaction (since the decay heat generated by a spent fuel assembly decreases with the passage of time since the shutdown of the nuclear reaction), and (iii) how quickly the facility is capable of 1A' the Board views things, it is the use of the RilR for augmentation of SFP, necessitated by SFP heat carrying capacity insufficiency, that is the single failure criterion violation.
This is a correct interpretation of Contention 1.
However, were it so, as the Board is apparently inclined to find, that this is a violation that is equally inherent in present operations as it would be under authority to increase the spent fuel pool inventory above 2,000 assemblies (in that is now occurs 'every time there is a partial core offload"), then the proposed license amendment would not envision any change and the Contention should have been excluded.
8While it is true that, subsequent to the admission of Contention 1 Vermont Yankee has committed to the NRC Staff to install a supplemental spent ft el pool cooling sub system, with enhanced cooling capacity, Vermont Yankee has previously indicated its intention to defend against the Conten-tion on the ground that even the existing cooling system is more than adeq.: ate to carry anticipated heat loads, that there is no prospect of having to rely upon RilR for augmentation of SFP even in the event of a single active failure in the SFP system, and for this reason the Contention has (and had) no merit.
2
being refueled 'that is to say, the number of days of decay available before reliance upon the SFP cooling system will be required).
The existing SFP cooling system consists of two pumps, two heat exchangers, and piping sufficient to connect either or both of the heat exchangers to either of the pumps. It can operate in either of three modes:
(i) Two pumps and two heat exchangers; (ii) One pump and two heat ex-changers; and (iii) One pump and one heat exchanger. The heat exchangers and piping are ccnsidered passive components, while the pumps are con-sidered active components.
Given the most critical single active failure, therefore, the configuration of the system is one pump and two heat ex-changers.
The heat carrying capacity of the existing system, in each of three possible modes of operation and at a nominal inlet temperature of 125'F, has been calculated to be as follows:
Table 1r 1 P - 1 HX:
2.23 MBtu/hr @ 450 spm i P - 2 HXs 3.56 MBtu/hr @ 450 spm 2 Ps - 2 HXs 4.46 MBtu/hr @ 900 gpm.
See FSAR, Table 10.5.1.
All other parameters held constant, however, the heat carrying capacity of a heat exchanger increases as inlet temperature increases; as pool temperature increases to a limiting value of 150'F, the heat carrying capacity of the existing system, in each of three possible modes of operation, has been calculated to be as follows:
Table 2:
1 P - 1 HX:
5.7 MDtu/hr @ 450 spm 1 P - 2 HXs 9.1 MBtu/hr @ 450 spm 2 Ps - 2 HXs 11.5 MBlu/hr @ 900 spm.
See the response to Question IB contained in Attachment 2 of the Warren Murphy letter of 3/2/88. (Note that the 1 P - 2 HXs value in Table I is j
derived by interpolation.)
The critical case for determining the heat load that must be carried by the spent fuel pool cooling system is, as the Board correctly notes, at the time of restart following a 1/3 of the core offload (normal refueling). The feat load generated as a result of inserting 1/3 core freshly discharged o
+
spent fuel in the SFP depends primarily upon the number of days th'
.ve elapsed since shutdown of the nuclear reaction (and secondarily ur,.m t..
number of old spent fuel assemblies in the pool). Assurning a value of 50 days since shutdown of the nuclear reaction, the heat loads generated by this 1/3 core rejection have been calculated to be 8.12 MBtu/hr given an SFP inventory of 2,000 assemblies and 9.10 MBtu/hr given an SFP inventory of 2,870 assemblies. Viewed a slightly different way, the number of days from shutdown of the nuclear reaction required to reach the heat carrying f
capacity of the existing SFP caling system in each of its three modes of operation is as follows:
Table 3:
No, SFAs in Pool Days Decay to Capacity of:
After Refuel l P - I HX
) P - 2 HXs 2Ps - 2 HX, 2,000 43 6-7 3
2,870 69 10-11 4-5 t
4 While values of 6 and 10 days are often used for calculational purposes to determine heat loads, it is highly unlikely (and perhaps impossible) for 4
Vermont Yankes to be shut down, opened, defueled, refueled, readied for re-start, and restarted in 10 days after shutdown of the nuclesr reac'Ln, In j
fact, refuelings at Vermont Yankee have historically averaged 44 days in l
duration.
l The foregoing data demonstrates that, even given the most critical single 1
active failure, the existing SFP cooling system has adequate heat carrying capacity to carry the heat load generated by the rejected 1/3 ?f the core by f
the time the reactor will be ready for restart. This is truc Loth at 2,000 and at 2,870 spent fuel assemblies in the pool. It follows that relia"- - *n one of the trains of the RHR system to augment SFP cooling on cS"" :a r
an inadequacy in the SFP cooling system's heat carrying capacity hk. r...
occurred and will never occur, eitner prior to or after authorization to increase the maximum SFP inventory from 2,000 assemblies to 2,870 assem-
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Y, B.
Contrary to the Woerd's assertion, use of an RHR trala to augment SFP coolles on account of an leadequacy la the 4
SFP coolies system's heat carr>les capacity has meter occurred.
The Board's assertion that VYNPS relies 'on the (RHR] system every time there is a partial core offload," if latended in the sense of relying upon the capacity of one of the RHR trains to be switched to SFP cooling to c
augment the heat carrying capacity of the SFP cooling system during power J
operation, doet not occur at every refueling. In fact, although it is correct that the VYNPS RHR system does have this d) sign capacity, it has never been used due to spent fuel pool cecling inadequacy.' Nor do the materials cited by the Board, or the Appeal Board in roaching a similar conclusion, support this prow.ition of fact, though we perceive a measure of confusion as to how VYN' is operate.$ during a refueling.
I The Board should understand that the spent fuel pool is a water-containing sessel located essentially along-side of the reactor cavity.
JoinMg the SFP and it.e reactor cavity is a canal, the floor of which is above the top of sgnt fuel in the pool. While the reactor is operatlal. the SFP and the reactor are separue fluid systems, each depending upon separate cooling systems.
j i
For refueling, the following steps occur: the head is removed from the i
reactor vessel. The level of water in the reactor is increassd to fill the cavity and the canal with water. Finally, a gate in the canal ssparating the l
seactor cavity and the SFP is removed. At that polni the reactor and the
}
SFP become joined in that water can pass directly from one to the other (through the canal). (It is by this means that a spent fuel assembly can be removed from the reacter and placed in the pool whilst being kept under i
water during the entire operation.)
t While the systems are joined, the RHP. system, which would have been started prior to removal of the reactor henc' to :arry the re.idual heat in i
the reactor, remains runn53. The heat carryir.4 capacity of the RHR system l
is so large that the E ~ ) sys'em is capable of carrying the entire heat load i
m.ity to C %.CR Train A suction to the SFP sin fact, the syst i
h 15. The purpose at that time
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1 of the reactor and she SFP and one could shut off the SFP cooling system.
(The SFP system is normally left on, but this is related to water clarity and visibility, not cooling capacity.) However, so long as the reacMr and the SFP remain a single fluid system, any reliance upon the RiiR system to carry the heat from the SFP does not implicate the single failure critenlon, since both RHR trtins are available to do the job and since either RHR train is capabit of carrying the load. Assuming it is otherwise applicable to spent fuel pools, the single failure criterion does not become a fector until the operator wishes to insert the gate in the canal and separate the reactor and the SFP into separate fluid systems (requiring separate cooling systems).4 It is this description of how VYNPS (and,*in fact, all BWRs) operate that was the point of the langauge from the transcript first pre-hearing conference that the Board (and the Appeal Board) cited. The language at page 59 (cited both by this Board in its most recent Memo and Order and by the Appeal Board at 26 NRC at 21 & n.4), namely:
"That is true, it's true today and it's what we do when we offload a third of a core today and it's what has been going on in this plant for some time.'
refers to this proposition, though (given the imprecision of the transcription and the imprecision of the oral discussion then in progress) we admit that it is susceptible of being misinterpreted. However, immediately thereafter, at page 61 (cited by the Appeal Board loc. cit supra but not cited by this Board in its most recent Afemo and Order) the same speaker makes it clear what he is referring to:
"What's the difference whether we use it for a full core off-load or one-third core offload. We will use it any time that -- you don't have to hase a full core or a third of a core of anything.
You're designing for any possible offload, and the utilization of the RHR to cool the combination of the -- remember, the biggest prob-lem is when the gate is down and you're cooling both the RHR and the water in the vessel itself.
At that time we have historically used the RHR system and we have the right to use the RHR system l
for some time.'
l (Emphasis added.)
l Actually, even assuming its applice.bility, the criterion would not be-4 come applicable until the reactor were restarted, since prior to that time there is no requirement of redundant RHR trains on the reactor..
This Board also cites pages 55-56 and pages 77-78 of the transcript (not cited by the Appeal Board). At those pages the speaker is not a person associated with VYNPS, nor a person who anderstands how the reactoi is operated. The statements made on those pages are not factually correct.s C.
Even were an RHR train switched to SFP coollag, restart of the reactor cannot occur because it is precluded by the VYNPS Technical Specifications.
As noted above, overlooked by apparently everyone is the fact that the scenario of concern cannot occur consistent with the existing VYNPS techni-cal specifications. This, indeed, is pointed out in the same language as that cited by the Appea! Board:
- [The t}echnical specifications say that you can't restart the reactor without both RHRs being available. So there just simply is -- even if the single failure t.riterion applied to spent fuel pools..., it's met."
Tr. 01. It is also pointed out in one of the responses cited by the Appeal Board.'
'The Appeal Board also cited the response to items 13.17 and 18 contabed in a letter of Vermont Yankte to the Staff dated 11/24/86. With all due respect to the Appeal Board, it has misinterpreted thost responses.
The response to item 13 describes how YYNPS is capable of being operated, not how it has been operated in fact. It is true that, as a exercise in design flexibility and conservatism, YYNPS has the capability of switching one train of RilR from the reactor to the SFP (directly, that is, not via the refueling canal). That capability has never been used (for cooling).
l The response to item 17 is a calcalation of how long it would take decay heat to reach the point where it could be carried by the existing 3FP cooling system given a configuration of I pump and I heat exchanger. The number is correct, but that is not the single active failure configuration and the response does not say that VYNPS has in fact employed RHR cooling augmentation following a refueling.
l The response to item 18 fairly belies the implication drawn by the Appeal Board, for it points out that the existing VYNPS technical specifica-tions preclude restarting the reactor unless both RHR trains are available to the reactor. Thus, not only has the situation the hypothesis of which is the foundation of Contention 1 -- namely refueling, readiness to restart so quickly that the heat load of the pool exceeds the capacity of the SFP cooling system, switching of one RHR train to the pool, and then restart of the reactor -- never occurred, that situation canrot occur under the VYNPS technical specifications.
- See note 3, supra.
l l
7-
Thus, even if one were to assume occurrence of the most critical single active failure of the existing SFP cooling system, and ev" if one were to assume that all of the steps comprising refueling had been accomplished before the heat load of the pool had decayed to the point where it could be carried by the degra 1 SFP cooling system (that is to say, refueling had been accomplished in an impossibly rapid 6-7 days or faster), cnd even assumiLg that, in order to permit the removal of the canal gate and separa-tion of the reactor and the SFP fluid s/ stems, Vermont Yankee switched one of the RHR trains to the SFP, Vermont Yankee does not have, either now or following the authorization of the proposed amendment, authority to restart the reactor until availability of the RilR train (to the reactor) had been
- restored, liowever, unless the reactor is started, violation of the single failure criterion cannot be hypothesized.
Ill.
Conclusion.
Vermont Yankee rer.pectfully submits that the Board's statement regard-ing the on-going 'present... and apparent" violation of the single failure criterion at the VYNPS spent fuel pool is factually incorrect.
Vermont Yankee does not want the Board to continue under the impression that this is how the plant is operated, nor does Verment Yankee believe it to be appropriete for the Board to decide questions that come before it under the impression that celerity in deciding this proceeding is critical on account of som. on-going outstanding invasion of ',he health and safety of the put! c.7 Ry trully subtritted, 8
/
A k
John A. Ritsher R. K. Gad ill Kathryn A. Selleck Ropes & Gray 225 Franklin Street Boston, Massachusetts 02110 Telephone: 617-423-6100 7 Vermont Yankee does believe it to be important that this proceeding be concluded promptly, for other reasons. If this ware not a proceeding subject to Sub-part K of the Commission's Rules of Practice, Vermont Yankee would have submitted the within facts in the form of a motion for summary ditposition long ago.
It is believed by some, honeser, that summary disposition is not avail ble under Sub-part K.
3
Affidavit We, Donald A. Reid, John T. Herron, Jay K. Thayer, and Christopher Hansen, being first duly sworn, depose and say as follows:
1.
Mr. Reid is employed by Vermont Yankee Nuclear Power Corpora-tion and is Operations Support Manager.
He holds a Bachelor of Science Degree in Mechanical Engineering and is licensed as a Professional Engineer in the State of Vermont. Mr. Reid has 14 years experience in the nuclear industry at Vermont Yankee, where his positions have included Engineering Support Supervisor and Technical Services Superintendent.
2.
Mr. Herron is employed by Vermont Yankee Nuclear Power Corpora-tion and is Technical Program Manager.
Mr. Herron holds a Bachtlor of Science degree in Business Management. Mr. Herron has 16 years experience in the nuclear industry: 10 years at Vermont Yankee plus 6 years in the United States Navy Nuclear program. Mr. Herron has held such positions as Reactor Operator, Senior Reactor Operator and Shift Supervisor; Mr. Herron currently holds an NRC-issued license as a Senior Reactor Operator at Vermont Yankee.
3.
Mr. Thayer is employed by Yankee Atomic Electric Company and is the Engineering Manager for the Vermont Yankee Project.
His resptn-sibilities include direction of a staff of approximately 30 engineers, who perform design changes and engineering reviews and evaluations covering all aspects of plant design, modification, maintenance, licensing and outage support. Mr. Thayer holds a Bachelor of Science degree in Electric Engin-cering from Worcester Polytechnic Institute and has worked in the nuclear power field for 15 years, including operations and engineering positions at several pressurized water and boiling water reactors throughout New England.
4.
Mr. }lansen is employed by Yankee Atomic Electric Company and is a Senior Engineer assigned to i;,e Vermont Yankee Project.
His respon-sibilities include Spent Fuel Pool Cooling system design and analysis. Mr.
Hansen has 15 years of experience in nuclear electric power generation stations and 6 years experience as a Uttted States Navy Nuclear Propulsion Plant operator.
Prior to joining Yankee Atomic Electric Company, Mr.
Hansen was eniployed by Stone & Webster Engineering Cciporation, where he was responsible for initial plant design of various nuclear systems and tov 10 '06 15tSO P.2
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CERTIFICATE OF SERVICE
'g g g j
accordance with the rules of the Commission by mailing T(c6py..
1 I, R. K. Gad III, hereby certify that on F5u November 10, 1988, I made service of the within dolckfinleint inlm El.
thereof postage prepaid to the following Charles Bechhoefer, Esquire, Samuel H. Press, Esquire chairman George E. Young, Esquire
(
Administrative Judge Vermont Department of i
Atomic Safety and Licensing Public Sarvice j
Board Panel 120 State Street U.S. Nuclear Regulatory Montpelier, VT 05602 i
Commission Washington, DC 20555 Mr. Glenn O.
Bright Ellyn R. Weiss, Esquire t
Administrative Judge Harmon & Weiss Atomic Safety and Licensing Suite 430 j
Board Panel 2001 S Street, N.W.
U.S. Nuclear Regulatory Washington, DC 20009 i
Commission Washington, DC 20555 Mr. James H. Carpenter George B. Dean, Esquire Administrative Judge Assistant Attorney General Atomic Safety and Licensjag Department of the Attarney
}
Board Panel General e
i U.S. Nuclear Regulatory one Ashburton Place Commission Boston, MA 02108 l
Washir gton, DC 20555 Adjudicatory File Ann P. Hodgdon, Esquire Atomic Safety and Licensing office of the General Counsel Board Panel Docket (2 copies)
U.S. Nuclear Regulatory i
U.S. Nuclear Regulatory Commission Consission l
Washington, DC 20555 Washington, DC 20555 i
Atomic Safety and Licensing Geoffrey M. Huntington, Esquire I
I Appeal Board Panel office of the Attorney General U.S. Nuclear Regulatory Environmental Protection Bureau Commission State House Annex l
Washington, DC 20555 25 Capitol Street i
Concord, NH 03301-6397
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R. K. Gad IJi