ML20011F381
| ML20011F381 | |
| Person / Time | |
|---|---|
| Site: | FitzPatrick  |
| Issue date: | 02/26/1990 |
| From: | Labarge D Office of Nuclear Reactor Regulation |
| To: | Brons J POWER AUTHORITY OF THE STATE OF NEW YORK (NEW YORK |
| References | |
| RTR-REGGD-01.097, RTR-REGGD-1.097 TAC-51090, NUDOCS 9003050255 | |
| Download: ML20011F381 (2) | |
Text
. s 3
z.
February 26, 1990 2.Di.s.tribution:
- Docket No. 506333-nm s PDI-1-Rdg' i
RCapra CYogan Mr. John C. Brons DLaBarge Executive Vice President - Nuclear Generation OGC Power Authority of the State of New York ACRS(10)
I 123 Main Street-JLinville White Plains, New York 10601 EJordan Plant File
Dear Mr. Brons:
SUBJECT:
POST-ACCIDENT NEUTRON FLUX MONITORING (TAC N0. 51090)
Regulatory Guide (RG) 1.97 and 10 CFR 50.49 require that neutron flux be monitored by Category 1 instrumentation.
However, the staff has allowed BWRs to operate with existing instrumentation until instrumentation was developed that conforms to the requirements of RG 1.97 and 10 CFR 50.49. The safety evaluation and related technical evaluation report for the James A.
FitzPatrick Nuclear Pcwer Plant which discussed this position was transmitted to you by letter dated March 14, 1988.
TheBoilingWaterReactorOwnersGroup(BWROG)submittedtheLicensingTopical Report (General Electric Report NEDO 31558) for NRC review and approval by letter dated June 13, 1988 fromD.N. Grace (BWOG) tot.T. Martin (NRC).
It proposed functional criteria for post-accident neutron flux monitoring as an alternative to the Category I recomendations specified in RG 1.97.
- Based on our review of the issue, the staff concludes that a Category 1 designation and associated lower range for neutron flux monitoring equipment is a)propriate. Therefore, the proposed NEDO 31558 document is unacceptable and tie neutron flux monitoring equipment must be environmentally qualified to comply with 10 CFR 50.'49.
Attached is a copy of the letter and safety evaluation which was sent to the BWROG.
Sincerely, ORIGINAL SIGNED BY:
David E. LaBarge, Project Manager Project Directorate I-1 Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation
Enclosure:
As stated cc: See next page PDI-1 PDl-1 PDI-1T CVogan DLaBarge:rsc RACapra 2/ @ /90 2//3 /90 2/26/90 f0k m
m3oEn1883}h 9
N P
{^,' c air.;aunn G ~orons i
- Power Authority of the State of New York James A. Fit: Patrick Nuclear Porer Plant
' ~.
1 pg CC;
'Mr. Gerald C. Goldstein
" Assistant-General Counsel Ms. Donna Ross
- t Power Authority of the State New York State Energy Office of New York 2 Empire State Plaza-1633 Broadway 16th Floor New York, New York 10019 Albany, New York 12223 Resteent Inspector's Office I
U.- S. Nuclear Regulatory Commission Regional Administrator, Region i Post Office Box 136 U.- S. Nuclear Regulatory Comission.
475 Allendale Road Lycoming, New York 13093 KingofPrussia, Pennsylvania 19a06 Mr. William Fernandez
-t Resident Manager Mr. A. Klausman James A. FitzPatrick Nuclear Senior Vice President - Appraisal J
Power Plant and Compliance Services Post Office Box 41 Power Authority of the State of New York t
Lycoming, New York 13093
Director Nuclear Licensing - BWR Mr. George Wilverding, Manager Power Authority of the State Nuclear Safety Evaluation uf New York Power Authority of the State 123 Main Street of New York 123 Main Street White Plains, New York 10601 L
White Plains, New York 10601 Supervisor j
Town of Scriba tir. R. E. Beedle R. D. #4 Vice President Nuclear Support Oswego, New York 13126 Power Authority of the State of New York 123 Main Street ffr. J. P. Bayne, President White Plains, New York 10601 Power Authority 09 the State of New York 1633 Broadway ftr. S. S. Zulla New York, New York 10019 Vice President Nuclear Engineering l
I Power Authority of the State l
of New York ftr. Richard Patch 123 tiain Street Quality Assurance Superintendent White Plains, New York 10601 James A. Fit: Patrick Nuclear Power Plant Post Of' ice Box 41 Mr. William Josiger, Vice President Lycoming, New York 13093 Operations and Maintenance Power Authority of the State of New York 123 Main Street Charlie Donaldson, Esquire Assistant Attorney General White Plains, New York 10601 New York Department of Law 120 Broadway New York, New York 10271
p
^
t
[
~*'
4 4
UNITED STATES
! 'c s
NUCLEAR REGULATORY COMMISSION
~
a
\\
5 I
k......
WASHINGTON O. C 20065 January 29, 1990 Mr. Stephen D. Floyd, Chairman-BWR Owners' Gro9p-Carolina Power and Light 411 Fayetteville Street.-
Raleigh, NC. 27602-
Dear Mr. Floyd:
SUBJECT:
BWR OWNERS' GROUP LICENSING-TOPICAL REPORT " POSITIO REGULATORY GUIDE 1.97,-REVISION 3 REQUIREMENTS FOR POST-ACCIDENT NEUTRON MONITORING SYSTEM" (GENERAL ELECTRIC NE00-31558)
References:
1)
BWR Owners' Group letter (R. F. Janecek) to NRC (T. E.
Murley), "BWR Owners' Group Licensing Topical Report
" Position on NRC Regulatory Guide 1.97, Revision 3 Requirements for Post-Accident Neutron Monitoring System" (General Electric Report NED0 31558), April 1, 1988.
2)
BWR Owners' Group letter (D. N. Grace) to NRC (T. T.
Martin),'"BWR Owners' Group Licensing Tepical Report
" Position on NRC Regulatory Guide 1.97, Revision 3 Requirements for Post-Accident Heutron Monitoring System" (General Electric Report NEDO 31558), June 13, 1988.
Reference 2 requested that the staff expedite its review of Reference 1.
Reference 1 submitted the-BWR Owners' Group (BWROG) Licensing Topical Report (LTR) for staff review and approval.
The LTR proposed functional criteria-for post-accident neutron flux monitoring as an alternative to-the Category 1 recommendations specified in Regulatory Guide (R.G.) 1.97.
1 Based on our review the staff concludes that a Category 1 designation, and associated lower ran,ge for neutron flux monitoring equipment is appropriate.
Therefore, the proposed LTR NEDO-31558'is unacceptable and the neutron flux monitoring equipment must be environmentally qualified to comply with 10CFR50.49.
If you have any questions regarding the above information, please contact Barry Marcus, of my staff on 49-20776.
Sincerely,
)
M Frank J.
traglia, Associate Director for Inspection and Technical Assessment Office of Nuclear Reactor Regulation
Enclosure:
SER cc w/ enclosure:
A.Udy'(EGAGIdaho)
-Whkb5 If
(;;
V u
ENCLOSURE 1
L SAFETY' EVALUATION REPORT BWROG LICENSING TOPICAL REPORT NEDO-31558.
POSITION ON REGULATORY GUIDE 1.97 REQUIREMENTS FOR POST-ACCIDENT NEUTRON FLUX MONITORING SYSTEM.
1.0 INTRODUCTION
By letter dated June 13, 1988, the Boiling Water Reactor Owners' Group (BWROG) requested that the staff expedite its review of BWR06 Licensing Topical Report (LTR) NED0'31558 " Position on NRC Regulatory Guide (R.G.) 1.97, Revision 3, Requirements for Fost-Accident Neutron Monitoring Syst'em", submitted by letter l.
dated April 1, 1988.
The LTR provides an event analysis of selected postulated:
I events where post-accident neutron. flux monitoring instrumentation might be required. the effect of neutron flux monitoring instrumentation failure, and proposed functional criteria based on the event analysis.
L"
2.0 BACKGROUND
s The following is a' chronology of events for neutron flux monitoring as related
-to R.G. 1.97:
In December 1980, R.G.1.97, Revision 2, was issued recomanding that Category 1 neutron flux monitoring instrumentation be used to monitor reactivity control in boiling water reactors (BWRs).
In March 1983, based on a number of surveys within the nuclear power
[
industry it was concluded, by the staff, that existing neutron flux monitoring instrumentation that was available to the industry did not conform to the criteria of R.G. 1.97. However, the staff was informed that instrumentation to conform to the criteria of R.G.1.97 was under development.
)&!b0$Y f
N i
2 Beginning.Febrbary 1985, with the issuance of the first R.G.1.97 Safety -
Evaluation Reports (SERs), the staff acknowledged that. fully qualified-neutron flux monitoring systems were not available and instructed applicants and licensees to follow industry development and install qualified neutron flux monitoring systems when they became available, d
The'SERs also included acceptance of existing neutron monitoring systems for interim.use until fully qualified neutron flux monitoring systems l
became available.
Early in 1987, the staff was informed that fully qualified neutron flux monitoring systems were now available to the nuclear power industry.
Beginning in December.1987, R.G.1.97 SERs acknowledged that industry
]
had developed neutron flux monitoring systems that meet the R.G. 1.97 j
l criteria and instructed applicants and licensees to evaluate these newly-
~
developed systems and install neutron flux monitoring instrumentation which complies with the Category 1 criteria of R.G. 1.97. The SERs also
'{
included acceptance of existing neutron flux monitoring systems for i
interim use until fully qualified neutron flux monitoring systems were installed.
L R.G. 1.97 recommends Category 1 neutron flux monitoring instrumentation to monitor reactivity control during post-accident situations.
R.G. 1.97 specifies neutron flux as a key variable for deterinining the accomplishment
{
of reactivity control because it is a direct measurement and not an indirect lagging indication. The regulatory guide specifies that Category 1 systems should be environmentally qualified.
10 CFR 50.49 explicitly references this regulatory guide and therefore requires that all-Category 1 equipment shall be environmentally qualified.
Existing installed neutron flux monitoring instrumentation typically do not meet these environmental qualificatim requirements for detectors, cables, and detector drive mechanisms. Some existing systems are not powered by Class 1E power supplies.
L'
.j,
- 3'-
R.G.1.97 recomends that the neutron flux monitoring instrumentation be L
capable of monitoring a: range of 10-6% to 100% full power.
Initiating and post reactor shutdown events could involve environmental conditions more o
extreme than the conditions the typical existing neutron flux monitoring
}
instrumentation was designed to operate in. Neutron flux monitoring instrumentation capable of monitoring readings down to the 10-6% power level-
- must be able;to operate satisfactorily.in these extreme environmental conditions. The instrumentation must be reliably in place inmediately after initial shutdown, and be fully operable for an extended period of time, i.e.,
i in the order of six hours, 3.0 EVALUATION 1
4 The LTR provides a discussion of BWR safety analyses relevant.to post-accident l
neutron flux monitoring-instrumentation requirements and uses the results of 1
.the analyses to establish functional design criteria. These criteria include several deviations from the recomendations of R.G.1.97.
Among these
. deviations is a proposed " alternate" requirement for the range recomendation of the neutron flux monitoring system (LTR Section 5.2.1), reducing the R.G.
1.97 recomendations of 10-6% to 100% power to an " alternate" of 1% to 100%
power. This in effect would eliminate any requirement (for this purpose) for the source range monitor (SRM) and intermediate range monitor (IRM) instruments, i
The LTR justifies this alternate requirement by examining representative extreme events selected frem the ranga of FSAR and ATWS events. The analyses and related considerations such as the availability of alternate monitoring equipment (e.g., control rod position indication or boron concentration measurements) are based on anticipated conditions resulting from standard y
event analyses.
These might normally be considered as reasonably comprehensive for, e.g., FSAR design bases analyses. However, at least some of the instrumentation recomendations of R.G.1.97 were intended to cover a wider range of possibilities, including conditions not necessarily to be anticipated by following the usually clearly defined paths of standard event
[,,
-4.
I analyses.
In particular, the proposed elimination of the 104% to 15 power portion of the range would delete a primary purpose of the post-accident neutron flux monitoring instrumentation. This purpose was intended to provide, with maximum forewarning time, operator information-(via indications of-deviations from normal post shutdown flux levels) warning of possible post event approaches or return to a critical state. This might be under circumstances which would involve reactor. states and evolving events and conditions not anticipated from analyses following normally considered event scenarios.
It would thus be virtually impossible to either predict or e
demonstrate the implausibility of such event paths and resulting conditions with assurance.
Therefore, while not disputing the analyses or results presented in the LTR, it must be concluded that they do not address the above conceptual basis that r
I set the low power rcnge recommendations of R.G. 1.97.
The required power level is set by expected flux levels existing for some extended period of time (in
- the order of several hours) after shutdown and for reactivity status and neutron (installed and operational) source levels resulting from normal rapid shutdown from power operation. The normal flux levels serve as a base for observable deviations of anomalous ?eactivity states in the (unknown) anomalous events indicated above.
10CFR50.49 requires that certain post-accident monitoring equipment (Category 1 and 2) be environmentally qualified. Therefore, based on the above evaluation, the staff continues to conclude that the Category 1 designation is appropriate and neutron flux monitoring equipment must be environmentally qualified to comply with 10CFR50.49.
To provide suitable interpretation, neutron flux monitoring detectors internal to the pressure vessel (e.g., in standard SRM locations) appear to be preferable, but neutron flux monitoring detectors external to the pressure vessel (e.g., in the drywell) could be considered. The chosen neutron flux l
monitoring system, should be operational during degraded core cooling conditions leading to some fuel clad failure, but not significant clad or fuel i
melting.
Environmental conditions external to the pressure vessel to be
(L.
t.,,.
.V
.s.
I considered should include high temperature, high _ humidity, radiation, and possible flooding,'associ,ated with external LOCA conditions. Fire conditions which might affect control rod actuation and/or position readout and thus i
~ require'the use of the low range neutron flux monitoring instrumentation
~
should also be considered.
Because the functional criteria proposed in the LTR does not meet the requirements of 10 CFR 50.49, the LTR functional criteria is unacceptable.
The staff has been informed that industry has-developed and made available, to the nuclear power industry, at least two different wide range neutron flux monitoring systems that satisfy all the Category ~1 criteria of R.G.1.97.
Therefore, it is the staff's position that BWR licensees should evaluate these newly developed systems and install neutron flux monitoring instrumentation which fully complies with the Category I criteria of R.G.1.97, i
4.0 CONCLUSION
Based on our review, the staff concludes that, as an alternative to the Category 1 criteria of R.G. 1.97, the prepcsed LTR NEDO-31558 functional criteria for post-accident neutron flux monitoring instrumentation-is l
unacceptable.
1+
l l
It is also concluded that the proposed alternate range requirement of LTR Section 5.2.1.1% to 1005 power does not meet the intent of R.G.1.97, and is therefore unacceptable. The range of neutron flux monitoring instrumentation should remain 10-6% to 100% power.
It is the staff's position that BWR licensees should install neutron flux monitoring instrumentation that fully complies with the Category 1 criteria of R.G. 1.97 and 10 CFR 50.49.
.