JPN-87-033, Informs of Licensee Rev to Commitment to Upgrade Reactor Vessel Water Level Instrumentation Per Rev 2 to Reg Guide 1.97.Mod Schedule Unchanged.Detailed Justification for Changes to Implementation of Upgrade Encl
| ML20215A858 | |
| Person / Time | |
|---|---|
| Site: | FitzPatrick  |
| Issue date: | 06/09/1987 |
| From: | Brons J POWER AUTHORITY OF THE STATE OF NEW YORK (NEW YORK |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| RTR-REGGD-01.097, RTR-REGGD-1.097 GL-84-23, JPN-87-033, JPN-87-33, NUDOCS 8706170116 | |
| Download: ML20215A858 (8) | |
Text
-,
123 Main street i
WNte Plains, New Ymk l0601 -
-914 681.6200 -
i
- > NewYorkPbwer 1aff Authori1Y i
i 4
i June 9.,
1987 JPN-87-033 q
U.
S.
Nuclear Regulatory Commission
]
Attn. Document Control Desk
.)
Washington, D.
C.
20555 i
Subject:
James A.
FitzPatrick Nuclear Power Plant j
Docket No. 50-333 j
Revised' Implementation Plans for j
Regulatory Guide 1.97 Reactor Vessel-Water Level Instrumentation
References:
- 1. NYPA letter, C. A. McNeill, Jr. to' D. B. Vassallo, dated November 30, 1984 (JPN-84-077) regarding implementation of Revision 2 to Regulatory-Guide 1.97.
Dear Sir:
In Reference 1, the Authority described plans.for implementing Revision 2 of Regulatory Guide 1.97 at the FitzPatrick nuclear power plant.
After completing a detailed engineering study, the Authority has reevaluated plans for upgrading the reactor vessel water level instrumentation.
As a result, the Authority is revising the commitment for upgrading this instrumentation.
However, the schedule for installing these modifications remains unchanged.
Three changes will be made to the modifications described in Section 4.2 of Reference 1: (1) a reduced range will be implemented; (2) a second, electrically redundant Shutdown Range instrument will not be added, and; (3) the Shutdown Range instrument will not be upgraded to meet P
po03-ult.
Class 1E requirements. -Detailed justification;for these changes is attached.
Should you or your staff have.any questions concerning this matter, please contact Mr.. J.,A.
Gray, Jr. of my staff.
Very truly.yours, we ohn C.
Brons Executive Vice. President Nuclear Generation 1
cc: U.
S.
Nuclear Regulatory Commission 631 Park Avenue King of Prussia, Pennsylvania 19406 Office of the Resident Inspector U.
S. Nuclear Regulatory Commission P.
O.
Box 136 Lycoming, New York 13093 Mr. H. Abelson, Project Manager Project Directorate I-1 Division of Reactor Projects - I/II U. S.
Nuclear Regulatory Commission j
7920 Norfolk Avenue i
Bethesda, Maryland 20014
ll Attachment to JPN-87-033 NEW YORK POWER AUTHORITY James A.
FitzPatrick Nuclear Power Plant Detailed Description of Changes to Plans Regarding Implementation of Regulatory Guide 1.97, Revision 2 Reactor Vessel Water Level Instrumentation q
.1 1.
Introduction l
In Reference 1, the Authority described plans for j
implementing the guidance of Revision 2 of Regulatory Guide i
1.97, " Instrumentation for Light-Water-Cooled Nuclear Power Plants to Assess Plant and Environs Conditions During and Following an Accident" (Reference 2).
The PoLition Summary j
Table, Reference 1, summarized the extent to which the FitzPatrick plant complied with Regulatory Guide 1.97 guidance.
Entries A3 and B4 of the position table enumerated two areas where the existing reactor vessel water level instrumentation did not meet the guidance of
)
Regulatory Guide 1.97 for instrument range and control room indication.
The existing water level instrumentation does meet the guidance for category classification, quality i
assurance, environmental qualification, seismic qualification, redundancy, and power supply.
The Regulatory Guide recommends an instrument range from the " Bottom of core support plate to lesser of top of vessel or centerline of main steam line."
It also recommends that control room indication be " continuous and.
one channel recorded."
In Section 4.2 (URPV Water Level A-2, B-4" on p. 11) of Reference 1, the Authority committed to meet the Regulatory Guide by modifying the instrumentation as follows:
"The range of existing RPV Water level instruments will be extended to meet the recommendations of the Regulatory Guide.
This will be accomplished by recalibrating one existing instrumentation channel and adding a second channel with trend recording."
After completing a detailed engineering study, the Authority has re-evaluated its plans for upgrading the reactor vessel water level instrumentation.
As a result, wrm nos-
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the Authority is revising its commitment for upgrading this instrumentation.
Three changes will be made to the level instrumentation modifications described in Section 4.2 of-Reference 1:
q
- a. a reduced range will be implemented,
- b. the second, electrically. redundant shutdown Range instrument (including a second channel of. trend recording) will not be added, and
- c. the Shutdown Range instrument will not be upgraded to meet Class 1E requirements.
2.
Existing Reactor Level Instrumentation FitzPatrick currently has three, overlapping reactor vessel level instrument ranges:
b Reactor Level Instrumentation Shutdown Range - 164.5 to 564.5 inches above TAF j
Wide Range - 14.5 to 224.5 inches above TAF Fuel Zone Range - 100 inches below to 200 inches'above TAF (TAF = Top of' Active Fuel.
The centerline of the main steam-lines is 288 inches above TAF.
Water level during normal operation is 201.5 inches above TAF.
Narrow Range instrument range is 164.5 to 224.5 inches above TAF.)
Both the Wide Range and Fuel Zone instrumentation have electrically and physically redundant channels.
Both meet the qualification requirements of NUREG-0588; and are powered from Class 1E power sources.
Level displays are I
continuously available in the control room and provide input signals for SPDS/ EPIC (Safety Parameter Display
'O System / Emergency and Plant Information Computer).
These instruments also automatically initiate safety systems and are used during normal operation.
As part of modifications to implement Regulatory Guide 1.97, the Fuel Zone instrument will be recalibrated to cover a range from 150 inches below TAF to 200 inches'above TAF.
This range includes the full active length of fuel.
The capability to record water level trends will be added to one -\\
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channel of the Wide _ Range instrument.
Additional information on the FitzPatrick reactor vessel water level instrumentation is available in the updated FSAR (Reference 3).
3.
Reduced Reactor Water Level Instrument Range The Authority will provide reactor vessel water level instrumentation complying with the guidance of Revision 2 to Regulatory Guide 1.97, with the exception of the instrument range.
The FitzPatrick instrument will have a range from i
the bottom of the core to a point approximately 64 inches below the center line of the main steam lines (i. e. 224.5
)
inches above TAF).
The Authority considers that this reduced range complies with the intent of the Regulatory Guide and is
]
justifiable.
As listed in Table 1 of Regulatory Guide 1.97, J
the purpose of reactor vessel water level instrumentation is 1
detection, mitigation, and long-term surveillance.
These functions can be fulfilled usir j the Wide Range and Fuel Zone Range instruments.
The upper-most 64 inches of range is not significant; water level and consequently adequate core cooling can be confidently confirmed without this 4
portion of the range.
i To provide the additional 64 inches of range between the centerline of the main steam lines (288 inches above TAF) and the current upper limit of the Wide Range instrument (224.5 inches above TAF), the Shutdown Range instrumentation would have to be modified.
There are two limitations associated with this instrument that preclude this from being done cost effectively.
Both limitations stem from the original design j
goals for the Shutdown Range instrument which was designed to monitor water level while filling the vessel in i
preparation for refueling.
This instrument range extends to the top of the reactor vessel (564.5 inches above TAF).
It was not designed to be used during or following an accident.
Specifically, the two limitations are:
- a. The cold reference leg for the Shutdown Range instrument has a vertical drop inside the drywell of approximately forty (40) feet.
Rerouting the leg outside the drywell to minimize the vc +.ical drop is not feasible because there is no un 4cd penetration that could be used to reduce the vertical drop to acceptable limits.
The addition
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of a new penetration would be very costly.
- b. A second, redundant Shutdown Range reactor vessel level instrument cannot be installed because a pair of redundant reactor vessel taps (level sensing lines) are not available.- A new level transmitter would have to use the same taps as the existing Shutdown Range-instrument.
Therefore, the Shutdown Range instrument cannot be modified to be accurate, reliable andefully redundant in a post-accident situation without excessive expense in terms of capital cost and personnel radiation sxposure.
Regardless of. expense, the Authority does not consider a modification'to the reactor vessel to add new level-taps to j
be advisable based solely on goo 6' engineering judgement.
- 4. Shutdown Randa Instrumen* Qualifidction The Shutdown Range instrument will not be upgraded to meet Class 1E requirements because it would not significan'tly improve anJoperator's ability to monitor water level inside the reactor vessel in the event of an accident.
Limitations, inherent in the system, would remain to make the instrument unsuitable for post-accident monitoring.
The potential for significant indication errors due to reference leg flashing,' and the lack of.a fully redundant instrument, would remain eve.n,if the instrument were upgraded to meet Class IE reg!!iretjats.
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Considering these limitations, the Shutdown'nange instrument should,not, and will not, be relicd upon following an accident.
[
- 5. schedule i
The schedule for installing ' this modification remains unchang9C.
As the Authority committed in Reference 4, the modifications required to install this instrumentation will be completed:
"/
' J'30 days after the end of the l'987 Refueling
- outage (Reload 8/ Cycle 9). or April 1-1988 whichever is later."
o However, the Authority's ability td ' meet this schedule is dependent upon tde NRC'c concurrence Oith the technical approach described id this attachment.
(Reload 8/ Cycle 9 was planned for 1987 when the Authority prepared Reference ?
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i 4.
Since 1935, the schedule has been revised and Reload 8/ Cycle 9 is currently scheduled for 1988.
This does not i
conflict with the NRC's December.12, 1985 confirmatory order H
for. implementation of Regulatory Guide 1.97, Reference 7.)
l
- 6. Other Planned Level Instrument Modifications To comply with Generic Letter No. 84-23 (Reference 2),
the Authority will install other modifications to improve the accuracy and reliability of the reactor vesrel level instrumentation.
As discussed in the Generic Letter, high drywell temperature in conjuction with. reactor depressurization can cause instrument line flashing and rignificant errors in level indication.
Flashing can. occur when vessel pressure drops to a point where the temperature of the line is above the saturation temperature.
The.
magnitude of this error depends upon line length.[ vertical I
drop], vessel pressure and pressure change rate.
Generic Letter 84-23 states that the:
4 l
" Maximum drop should allow an indicated level at the bottom of the normal' operating range when actual level is just above lower tap for worst flashing condition."
1 New cold reference legs will be-installed for both the Wide Range and Fuel Zone reactor vessel level instruments.
These new reference legs will be designed and-installed so that the FitzPatrick plant will comply with the requirements of Generic Letter 84-23.
This will effectively preclude errors caused by reference leg flashing.
They will be installed in accordance with the same schedule the Authority committed to for completing the Regulatory Guide 1.97 reactor vessel level modifications (Reference 6.)
The W'ide Range and Fuel Zone instrumentation will further comply with NUREG-0737, Item II.F.2 -
Instrumentation for Detection of Inadequate Core Cooling, range requirements.
Specifically, Item II.F.2 requires that instrumentation span the " full range from normal operation to complete core uncovery."
- 7. Notes and References
- 1. NYPA letter, C. A. McNeill, Jr. to D.
P. Vassallo, dated November 30, 1984 (JPN-84-077) regarding implementation of Regulatory Guide 1.97, Revision 2.
.4 i
- 2. NRC Regulatory Guide 1.97, Revision 2,.
" Instrumentation for Light-Water-Cooled Nuclear Power Plants to Assess Plant and Environs Conditions During and Following an Accident."
1
- 3. Updated FitzPatrick FSAR, Section 7.8.5.2,
" Reactor Vessel Water Level," Tables 7.8-1 " Reactor Vessel Level Instrument Specifications," Figure'7.8-2
" Reactor Vessel Instrumentation (P&ID)."
j i
- 4. NYPA letter, J.
C.
Brons to D.
B. Vassallo, dated June'
)
28, 1985 (JPN-85-053) regarding Regulatory Guide 1.97 J
Post-Accident Instrumentation Modifications.
Includes revised implementation schedule.
5.
NRC Generic Letter No. 84-23, " Reactor Vessel Water f
Level Instrumentation in BWRs," dated October 26,
)
1984.
J
- 6. NYPA letter, C. A. McNeill, Jr. to D.
B. Vassallo, dated December 13, 1984 (JPN-84-083) regarding Generic Letter 84-23.
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7.
NRC letter, D. R. Muller to J.
C.
Brons, dated December 11, 1985 include Order modifying license J
confirming additional licensee commitments on f
emergency response capability (supplement 1 to i
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