View source for B12240, Application to Amend License DPR-65,revising Tech Specs to Reduce Frequency of Surveillance Requirement for Determining Reactor Coolant Flow Rate.Fee Paid

{{Adams
| number = ML20197C774
| issue date = 10/24/1986
| title = Application to Amend License DPR-65,revising Tech Specs to Reduce Frequency of Surveillance Requirement for Determining Reactor Coolant Flow Rate.Fee Paid
| author name = Bishop R, Opeka J
| author affiliation = NORTHEAST NUCLEAR ENERGY CO., NORTHEAST UTILITIES
| addressee name = Thadani A
| addressee affiliation = NRC OFFICE OF NUCLEAR REACTOR REGULATION (NRR)
| docket = 05000336
| license number = 
| contact person = 
| document report number = B12240, TAC-63133, TAC-63198, NUDOCS 8611070033
| package number = ML20197C777
| document type = OPERATING LICENSES-APPLIATION TO AMEND-RENEW EXISTING, TEXT-LICENSE APPLICATIONS &amp; PERMITS
| page count = 6
| project = TAC:63133, TAC:63198
| stage = Request
}}

=Text=
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NORTHEAST UTILITIES                                       o.nor.i Orrices seio n street. Beriin. connecticut 1            e   NrISaNcc-s P.O. BOX 270 cos ace m**a "*                                            HARTFORD, CONNECTICUT 06141-0270 k  L   J  $C,'(([,'g",
                          ,                                                     (203) 665-5000 October 24,1986 Docket No. 50-336 B12240 Office of Nuclear Reactor Regulation Attn:   Mr. Ashok C. Thadani, Director PWR Project Director #8 Division of PWR Licensing - B U. S. Nuclear Regulatory Commission Washington, D. C. 20555 Gentlemen:
Millstone Nuclear Power Station, Unit No. 2 Proposed Revision to Technical Specifications Surveillance Requirements - DNB Margin Pursuant to 10CFR50.90, Northeast Nuclear Energy Company (NNECO) hereby proposes to amend its Operating License, DPR-65, by incorporating the attached proposed change into the Technical Specifications of Millstone Unit No. 2.
The proposed change will reduce the frequency of the surveillance requirement (Technical Specification 4.2.6) for determining the reactor coolant flow rate from at least once per twelve (12) hours to at least once per thirty one (31) days.
The current surveillance requirement necessitates that the RCS flow rate be determined by using the steam generator delta P. The flow rate could be determined more accurately using a core power calorimetric calculation. How-ever, a calorimetric calculation can be reliably performed only at power levels well above the minimum power for Mode 1 because variables such as feedwater                             ,
flow are difficult to hold constant with minimal error at low power levels. Thus,                       '
there are periods of time in Mode I during which the cuorimetric cannot reliably i
be used. The proposed relaxation in the surveillance frequency will permit the                          1 l            use of the more accurate calorimetric flow measurement technique.
!            The currently employed measurement technique uses the steam generator delta P measurement. This is calibrated once per cycle to the calorimetric flow determined at the beginning of the cycle. The uncertainty associated with the current delta P measurement is, therefore, a combination of the uncertainties                           I associated with the calorimetric flow determination and the steam generator delta P instrumentation. The delta P uncertainty is a significant contributor to the total.
l 8611070033 861024                                    01 9'6 406ih 9 ki 0                                        i PDR     ADOCK 05000336                                8  I P                       PDR Q0' I 1
l

There are two (2) reasons why the steam generator delta P measurement introduces a significant uncertainty into the flow measurement. They are as follows:
: 1)   The wide range of the instrument. The uncertainty of instrumen-tation is usually represented as a percent of span.            For this instrument, the span is about double the design flow rate, resulting in a large measurement uncertainty.
: 2)   Delta P is not a direct measure of flow, rather, flow rate is inferred.
The delta P measurement can be related to flow as long as the flow geometry between the measurement taps remains unchanged. If, for example, the flow is reduced due to fouling in the steam generator tubes, then the delta P would increase. This would result in the indicated flow exceeding the actual flow.
The proposed change (Technical Specification page 3/4 2-13; see Attachment 1) would allow the calorimetric flow measurement to be made. This measurement is not affected by changes in RCS flow geometry such as crudding which is the major reason why flow would change during the course of a cycle. Therefore, the calorimetric flow measurement provides greater assurance that the actual flow is consistent with the accident analysis assumptions.
In order to obtain historical information, we monitored the delta P flow rate for the eleven (11) month period of July,1985 to June,1986. A review of the data showed there were no significant flow fluctuations during normal operation. An abnormal flow reduction would likely occur in a short time frame (less than 1 minute). If this event were not severe enough to activate the reactor protection system, the flow reduction 'is more likely to be picked up by changes in parameters other than steam generator delta P (e.g. RCS delta T). In fact, the steam generator delta P may perceive the event as an increase in RCS flow.
Thus, the decrease in RCS flow surveillance frequency will not result in an abnormal decrease in RCS . flow going undetected. In addition, a qualitative assessment of the RCS flow rate would continue to be conducted twice per day since Technical Specification Table 4.3-2 requires a channel check of RCS flow instrumentation (steam generator delta P) once per twelve hours.
NNECO has reviewed the attached proposed changes pursuant to 10CFR50.59 and has determined that they do not constitute an unreviewed safety question.
The probability of occurrence or the consequences of a previously analyzed accident have not been increased and the possibility for a new type of accident has not been created. There will not be an effect on any parameters and/or systems. The change only involves the frequency at which reactor coolant system flow rate is verified to be within the Technical Specification limit. The tests which are proposed to be used to verify RCS flow are currently being performed, so there is no additional testing required. Only the test frequency will change. NNECO has determined that the increased period between tests does not decrease assurance that any credible changes in RCS flow rate will be identified in sufficient time for appropriate corrective action.

NNECO has reviewed the proposed changes,in accordance with 10CFR50.92, and has concluded that they do not involve a significant hazards consideration in that these changes would not:
: 1. Involve a significant increase in the probability or consequences of an an accident previously evaluated. There are no credible RCS flow changes which could be detected by the current surveillance fre-quency and not by the proposed surveillance frequency. The proposed surveillance frequency will ensure that RCS flow is consistent with the accident analysis assumptions with no impact on protective boundaries.
: 2. Create the possibility of a new or different kind of accident from any previously analyzed. Since there are no failure modes associated with the change, there cannot be a new unanalyzed accident.
: 3. Involve a significant reduction in a margin of safety. Only the frequency of performing surveillance testing is proposed to be changed. This will allow for a more accurate flow determination.
The Commission has provided guidance concerning the application of standards in 10CFR50.92 by providing certain examples (51FR7750, March 6,1986). The changes proposed herein constitute a more accurate method of surveillance, with a decrease in test frequency and do not resemble any of the examples provided.
Using a measureme'nt technique which does not rely on the delta P instrumenta-tion would result in a substantial improvement in the accuracy of a flow measurement. The use of the calorimetric technique involves a reduction in surveillance frequency, but will provide a more accurate, reliable flow measure-ment. The resulting flow measurement has greater reliability due to elimination of sources of error associated with the current surveillance technique. The current margin of error is high due to the steam generator delta P measurement and steam generator crudding, which introduces a non-conservative error. The calorimetric method includes neither of the above mentioned errors, resulting in a more accurate, reliable calculational method. The proposed changes neither result in an increase to the probability or consequences of a previously analyzed accident nor reduce in some way a safety margin.
In summary, NNECO has concluded that the proposed changes do not constitute a                            l 1
significant hazards consideration for the following reasons:
: 1)    Millstone Unit No. 2 has been in commercial operation for over 10 years. Data recorded and reviewed on RCS flow rate demonstrates that the flow rate does not decrease signficantly over an operating cycle. Therefore, RCS flow rate data support the conclusion that the monthly surveillance frequency is adequate.                                                 l
: 2)    The secondary-side calorimetric method of calculating the RCS flow rate is a more accurate and reliable technique.
: 3)    A qualitative assessment of the RCS flow rate would continue to be conducted twice per day since Technical Specification Table 4.3-2 l
l
                                                                                                                   )

Y requires a channel check once per twelve hours of RCS flow instrumentation.
: 4)    Protection against dramatic changes in RCS flow rate is provided by a Reactor Protection System setpoint as listed in Technical Specifi-cation Table 3.3-2.
NNECO recognizes that the proposed change constitutes a substantial reduction in surveillance frequency. However, we believe that this change is both appropri-ate and justified for the above stated reasons.
The Millstone Unit No. 2 Nuclear Review Board has reviewed and approved the attached proposed revisions and has concurred with above determinations.
In accordance with 10CFR50.91(b), we are providing the State of Connecticut with a copy of these proposed amendments.
Although the license amendment request proposed herein is not directly related to the refueling outage curren'tly underway, NNECO requests that if approved, the NRC Staff issue the license amendment by December 9,1986, to support startup from the refueling outage. This amendment may be required at that time to address potential steam generator tube plugging and sleeving conducted during the outage, the precise scope of which is unknown at this time.
Pursuant to the requirements of 10CFR170.12(c), enclosed with this amendment request is the application fee of $150.
Very truly yours, NORTHEAST NUCLEAR ENERGY COMPANY Eth J. F. Opeka Senior Vice President
                                                                   'L ByTTC W. Bishop ^
Secretary cc:   Kevin McCarthy Director, Radiation Control Unit Department of Environmental Protection Hartford, Connecticut 06116

STATE OF CONNECTICUT )
                                                   ) ss. Berlin COUNTY OF HARTFORD             )
Then personally appeared before me R. W. Bishop, who being duly sworn, did state that he is Secretary of Northeast Nuclear Energy Company, a Licensee herein, that he is authorized to execute and file the foregoing information in the name and on behalf of the Licensees herein and that the statements contained in said information are true and correct to the best of his knowledge and belief.
Notary Publy '
MY COMMISSION EXPIRES MARCH 31,199f

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l                                                                                                   Docket No. 50-336 1
B12240
-l i
Attachment 1 Millstone Nuclear Power Station, Unit No. 2 Proposed Revisions to Technical Specification Surveillance Requirements - DNB Margin i
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s      s NORTHEAST UTILITIES                                            coner.i Ome.. . seio.n sire t. Beriin. connecticut 4 CMCW wt ama %4 cow.am-1          *nw v.amw s ucac cc-==                                     P.O. BOX 270
                                  .e w . ra .o.e. co***"                                     HARTFORD. CONNECTICUT 06141-0270 k   L   J [.Z C."2[,*'*'                                              (203) 66s-s000 October 24,1986 Docket No. 50-336 B12240 Office of Nuclear Reactor Regulation Attn: Mr. Ashok C. Thadani, Director PWR Project Director //8 Division of PWR Licensing - B U. S. Nuclear Regulatory Commission Washington, D. C. 20555 Gentlemen:
Millstone Nuclear Power Station, Unit No. 2 Proposed Revision to Technical Specifications Surveillance Requirements - DNB Margin Pursuant to 10CFR50.90, Northeast Nuclear Energy Company (NNECO) hereby proposes to amend its Operating License, DPR-65, by incorporating the attached proposed change into the Technical Specifications of Millstone Unit No. 2.
The proposed change will reduce the frequency of the surveillance requirement (Technical Specification 4.2.6) for determining the reactor coolant flow rate from at least once per twelve (12) hours to at least once per thirty one (31) days.
The current surveillance requirement necessitates that the RCS flow rate be determined by using the steam generator delta P. The flow rate could be determined more accurately using a core power calorimetric calculation. How-ever, a calorimetric calculation can be reliably performed only at power levels well above the minimum power for Mode 1 because variables such as feedwater flow are difficult to hold constant with minimal error at low power levels. Thus, there are periods of time in Mode 1 during which the calorimetric cannot reliably be used. The proposed relaxation in the surveillance frequency will permit the use of the more accurate calorimetric flow measurement technique.
The currently employed measurement technique uses the steam generator delta P measurement. This is calibrated once per cycle to the calorimetric flow determined at the beginning of the cycle. The uncertainty associated with the current delta P measurement is, therefore, a combination of the uncertainties associated with the calorimetric flow determination and the steam generator                                                     I delta P instrumentation. The delta P uncertainty is a significant contributor to                                                I the total.                                                                                                                      l l
1
                                                                                                                                                           \
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^
              .   .                                                                                                       l 1
;                        There. are two (2) reasons why the steam generator delta P measurement
:                        introduces a significant uncertainty into the flow measurement. They are as i                        follows:
: 1)     The wide range of the instrument. The . uncertainty of instrumen-tation is usually represented as a percent of span. For this instrument, the span is about double the design ~ flow rate, resulting in a large measurement uncertainty.
: 2)     Delta P is'not a direct measure of flow, rather, flow rate is inferred.
  ;                                   The delta P measurement can be related to flow as long as the flow geometry between the measurement taps remains unchanged. If, for L                                     example, the flow is reduced due to fouling in the steam generator tubes, then the delta P would increase. This would result in the
{                                     indicated flow exceeding the actual flow.
;                       The proposed change (Technical Specification page 3/4 2-13; see Attachment 1) -
j                        would allow the calorimetric flow measurement to be made. This measurement l                       is not affected by changes in RCS flow geometry such as crudding which is the 1
'                       major reason why flow would change during the course of a cycle. Therefore, the calorimetric flow measurement provides greater-assurance that the actual flow is consistent with the accident analysis assumptions.
     ~
In order to obtain historical information, we monitored the delta P flow rate for -
the eleven (11) month period of July,1985 to June,1986. A review of the data showed there were no significant flow fluctuations during normal operation. An 1
abnormal flow reduction would likely occur in a short time frame (less than 1 minute). If this event were not severe enough to activate the reactor protection i                      system, the flow reduction is more -likely to' be picked up by changes in
 !                      oarameters 'other than steam generator delta P (e.g. RCS delta T). In fact, the j
steam generator delta P may perceive the. event as an increase in RCS flow.
Ti'us, the decrease in RCS flow surveillance frequency will not result in an abrarmal decrease in RCS flow going undetected.~ In addition, a qualitative
^
asseament of the RCS flow rate would continue to be conducted twice per day since Technical Specification Table 4.3-2 requires a channel check ~ of RCS flow instrumentation (steam generator delta P) once per twelve hours.
1                      NNECO has reviewed the attached proposed changes pursuant to 10CFR50.59
 )                     and has determined that they. do not constitute an unreviewed safety question.
1 The probability-of occurrence or the consequences of a previously analyzed accident have not been increased and the possibility for a new type of accident i
has not been created. There will not be an effect on any parameters and/or systems.       The change only involves the frequency at which reactor coolant
,                      system flow rate is verified to be within the Technical Specification limit. The j                      tests which are proposed to be used to verify RCS flow are currently being -
4 performed, so there is no additional testing required. Only the test frequency                     i will change. NNECO has determined that the increased period between tests                          t
 ;                     does not decrease assurance that any credible changes in RCS flow rate will be j                     identified in suffi ic ent time for appropriate corrective action.
l I
l l

NNECO has reviewed the proposed changes, in accordance with 10CFR50.92, and has concluded that they do not involve a significant hazards consideration in that these changes would not:
: 1. Involve a significant increase in the probability or consequences of an an accident previously evaluated. There are no credible RCS flow changes which could be detected by the current surveillance fre-quency and not by the proposed surveillance frequency. The proposed surveillance frequency wi!! ensure that RCS flow is consistent with the accident analysis assumptions with no impact on protective boundaries.
: 2. Create the possibility of a new or different kind of accident from any previously analyzed. Since there are no failure modes associated with the change, there cannot be a new unanalyzed accident.
: 3. Involve a significant reduction in a margin of safety. Only the frequency of performing surveillance testing is proposed to be changed. This will allow for a more accurate flow determination.
The Commission has provided guidance concerning the application of standards in 10CFR50.92 by providing certain examples (51FR7750, March 6,1986). The changes proposed herein constitute a more accurate method of surveillance, with a decrease in test frequency and do not resemble any of the examples provided.
Using a measurement technique which does not rely on the delta P instrumenta-tion would result in a substantial improvement in the accuracy of a flow measurement. The use of the calorimetric technique involves a reduction in surveillance frequency, but will provide a more accurate, reliable flow measure-ment. The resulting flow measurement has greater reliability due to elimination of sources of error associated with the current surveillance technique. The current margin of error is high due to the steam generator delta P measurement and steam generator crudding, which introduces a non-conservative error. The calorimetric method includes neither of the above mentioned errors, resulting in a more accurate, reliable calculational method. The proposed changes neither result in an increase to the probability or consequences of a previously analyzed accident nor reduce in some way a safety margin.
In summary, NNECO has concluded that the proposed changes do not constitute a j       significant hazards consideration for the following reasons:                         l
: 1)    Millstone Unit No. 2 has been in commercial operation for over 10 years. Data recorded and reviewed on RCS flow rate demonstrates that the flow rate does not decrease signficantly over an operating cycle. Therefore, RCS flow rate data support the conclusion that the monthly surveillance frequency is adequate.
1
: 2)   The secondary-side calorimetric method of calculating the RCS flow rate is a more accurate and reliable technique.
: 3)   A qualitative assessment of the RCS flow rate would continue to be conducted twice per day since Technical Specification Table 4.3-2
__                 ~                  .

requires a channel check once per twelve hours of RCS flow instrumentation.
: 4)     Protection against dramatic changes in RCS flow rate is provided by a Reactor Protection System setpoint as listed in Technical Specifi-cation Table 3.3-2.
NNECO recognizes that the proposed change constitutes a substantial reduction in surveillance frequency. However, we believe that this change is both appropri-ate and justified for the above stated reasons.
The Millstone Unit No. 2 Nuclear Review Board has reviewed and approved the attached proposed revisions and has concurred with above determinations.
In accordance with 10CFR50.91(b), we are providing the State of Connecticut with a copy of these proposed amendments.
Although the license amendment request proposed herein is not directly related to the refueling outage currently underway, NNECO requests that if approved, the NRC Staff issue the license amendment by December 9,1986, to support          j startup from the refueling outage. This amendment may be required at that time to address potential steam generator tube plugging and sleeving conducted during the outage, the precise scope of which is unknown at this time.
Pursuant to the requirements of 10CFR170.12(c), enclosed with this amendment request is the application fee of $150.
Very truly yours, NORTHEAST NUCLEAR ENERGY COMPANY PcrA J. F. Opeka Senior Vice President s
W (2 By: lt. W. Bishop Secretary cc:   Kevin McCarthy Director, Radiation Control Unit Department of Environmental Protection Hartford, Connecticut 06116

STATE OF CONNECTICUT )
                                                                              ) ss. Berlin COUNTY OF HARTFORD                                 )
Then personally appeared before me R. W. Bishop, who being duly sworn, did state that he is Secretary of Northeast Nuclear Energy Company, a Licensee herein, that he is authorized to execute and file the foregoing information in the name and on behalf of the Licensees herein and that the statements contained in said information are true and correct to the best of his knowledge and belief.
Notary Publig MY COMMISSION EXFIRES MARCH 31,1991 l
I

NORTHEAST UTILITIES                                            o.nero Onic.. . seio.n street. seriin. connect cut 1         .w. mi.xw s uc'ac cow.                                    P.O. BOX 270 wo e a*sa *o.ra cev***                                      HARTFORD, CONNECTICUT 06141-0270 L L    J [.*,,,",'s, ((.' "$' '5~,                                    (203) 665-5000 October 24,1986 Docket No. 50-336 B12240 Office of Nuclear Reactor Regulation Attn:     Mr. Ashok C. Thadani, Director PWR Project Ditector #8 Division of PWR Licensing - B U. S. Nuclear Regulatory Commission Washington, D. C. 20555 Gentlemen:
Millstone Nuclear Power Station, Unit No. 2 Proposed Revision to Technical Specifications Surveillance Recuirements - DNB Margin Pursuant to 10CFR50.90, Northeast Nuclear Energy Company (NNECO) hereby proposes to amend its Operating License, DPR-65, by incorporating the attached proposed change into the Technical Specifications of Millstone Unit No. 2.
The proposed change will reduce the frequency of the surveillance requirement (Technical Specification 4.2.6) for determining the reactor coolant flow rate from at least once per twelve (12) hours to at least once per thirty one (31) days.
The current surveillance requirement necessitates that the RCS flow rate be determined by using the steam generator delta P. The flow rate could be determined more accurately using a core power calorimetric calculation. How-ever, a calorimetric calculation can be reliably performed only at power levels well above the minimum power for Mode 1 because variables such as feedwater flow are difficult to hold constant with minimal error at low power levels. Thus, there are periods of time in Mode 1 during which the calorimetric cannot reliably be used. The proposed relaxation in the surveillance frequency will permit the use of the more accurate calorimetric flow measurement technique.
The currently employed measurement technique uses the steam generator delta P measurement. This is calibrated once per cycle to the calorimetric flow determined at the beginning of the cycle. The uncertainty associated with the current delta P measurernent is, therefore, a combination of the uncertainties associated with the calorimetric flow determination and the steam generator delta P instrumentation. The delta P uncertainty is a significant contributor to the total, y         g #     /W //2o
                                 -     mv / v7 ,v

2
?       -
1
                                                                                ]
j                                     There, are two (2) reasons why the steam generator delta P measurement introduces a significant uncertainty into the flow measurement. They are as follows:
: 1) The wide range of the instrument. The uncertainty of instrumen-                           '
tation is usually represented as a percent of span. For this -
2 instrument, the span is about double the design flow rate, resulting in a large measurement uncertainty.
4
: 2) Delta P is not a direct measure of flow, rather, flow rate is inferred.
1 The delta P measurement can be related to flow as long as the flow geometry between. the measurement taps remains unchanged. If, for j                                                   example, the flow is reduced due to fouling in the steam generator j                                                    tubes, then the delta P would increase. This would result in the indicated flow exceeding the actual flow.
The proposed change (Technical Specification page 3/4 2-13; see Attachment 1) would allow the calorimetric flow measurement to be made. This measurement
                                  - is not affected by changes in RCS flow geometry such as crudding which is the
,                                    major reason why flow would change during the course of a cycle. Therefore, i                                   the calorimetric flow measurement provides greater assurance that the actual
;                                    flow is consistent with the accident analysis assumptions.
In order to obtain historical information, we monitored the delta P flow rate for f
the eleven (11) month period of July,1985 to June,1986. A review of the data showed there were no significant flow fluctuations during normal operation. An
 ;                                  abnormal flow reduction would likely occur in a short time frame (less than 1
;                                   minute). If this event were not severe enough to activate the reactor protection system, the flow reduction is more likely to be picked up by changes in parameters other than steam generator delta P (e.g. RCS delta T). In fact, the i
steam generator delta P may perceive the event as an increase in RCS flow.
l                                   Thus, the decrease in RCS flow surveillance. frequency will not result in an abnormal decrease in RCS flow going undetected. In addition, a qualitative assessment of the RCS flow rate would continue to be conducted twice per day i~                                  since Technical Specification Table 4.3-2 requires a channel check of RCS flow instrumentation (steam generator delta P) once per twelve hours.
;                                   NNECO has reviewed the attached proposed changes pursuant to 10CFR50.59 i                                  and has determined that they do not constitute an unreviewed safety question.
l                                  The probability of occurrence or the consequences of a previously analyzed' i                                  accident have not been increased and the possibility for a new type of accident j                                  has not been created. There will not be an effect on any parameters and/or-
;                                  systems. The change only involves the frequency at which reactor coolant i
system flow rate is verified to be within the Technical Specification limit. The tests which are proposed to be used to verify RCS flow are currently being performed, so there is no additional testing required. Only the test frequency will change. NNECO has determined that the increased period between tests j                                  does not decrease assurance that any credible changes in RCS flow rate will be 1                                  identified in sufficient time for appropriate corre ctive action.
   '.,. --__.,---..._---_..---_..-----__._-m-_._.                            -
                                                                                                                             - - - - ~ . _ . .

iI l
!                        NNECO has reviewed the proposed changes,in accordance with 10CFR50.92,tand                                                     ,
,                        has concluded that they do not involve a significant hazards consideration in that
,                        these changes would not:
                                                                                                                                                        +
1 l                                  1.            Involve a significant increase in the probability or consequences of an -
an accident previously evaluated. There are no credible RCS flow 3
changes which could be detected by the current surveillance fre-l                                               quency and not by the proposed surveillance frequency. The proposed                                    ,
j                                                surveillance frequency will ensure that RCS flow is consistent with the. accident analysis assumptions with no impact on protective i                                                boundaries.
j                                 2.             Create the possibility of a new or different kind of accident from any j                                                previously analyzed. Since there are no failure modes associated i                                                with the change, there cannot be a new unanalyzed accident.
: 3.             Involve a significant reduction in a margin of safety. Only the 2
frequency of performing surveillance testing .is proposed to be                                  '
changed. This will allow for a more accurate flow determination.
;                        The Commission has provided' guidance concerning the application of standards in 10CFR50.92 by providing certain examples (51FR7750, March 6,1986). The i                        changes proposed herein constitute a more accurate method of surveillance, with l                        a decrease in test frequency and do not resemble any of the examples provided.
!-                       Using a measurement technique which does not rely on the delta P instrumenta-j                        tion would result in' a substantial improvement in the accuracy of a flow                                            _
:                        measurement. The use of the calorimetric technique involves a reduction in i                        surveillance frequency, but will provide a more accurate, reliable flow measure-
!                        ment. The resulting flow measurement has greater reliability due to elimination of sources of error associated with the current surveillance technique. The~                                                   ;
current margin of error is high due to the steam generator delta P measurement
;                        and steam generator crudding, which introduces a non-conservative error. The i                        calorimetric method includes neither of the above mentioned errors, resulting in                                               ,
;                        a more accurate, reliable calculational method. The proposed changes neither                                                   l l                       . result in an increase to the probability or consequences of .a previously analyzed                                            !
l                        accident nor reduce in some way a safety margin.                                                     .
l j                        In summary, NNECO has concluded that the proposed changes do not constitute a                                              !!
4 significant hazards consideration for the following reasons:                                                               \
: 1)             Millstone Unit No. 2 has been in commercial operation for over 10                                      i years. Data recorded and reviewed on RCS flow rate demonstrates i                                                that the flow rate does not decrease signficantly over an operating                                    i cycle. Therefore, RCS flow rate data support the conclusion that the                                   i
;                                                monthly surveillance frequency is adequate.
t
;                                 2)             The secondary-side calorimetric method of calculating the RCS flow rate is a'more accurate and reliable technique.                                                         ,
!                                 3) '           A qualitative assessment of the RCS flow rate would continue to be                                      l
)                                                conducted twice per' day since Technical Specification Table 4.3-2 1
i I
i-                                                                                                                                                      i f

requires a channel check once per twelve hours of RCS flow instrumentation.
: 4)     Protection against dramatic changes in RCS flow rate is provided by
}                             a Reactor Protection System setpoint as listed in Technical Specifi-cation Table 3.3-2.
NNECO recognizes that the proposed change constitutes a substantial reduction in surveillance frequency. However, we believe that this change is both appropri-ate and justified for the above stated reasons.
The Millstone Unit No. 2 Nuclear Review Board has reviewed and approved the attached proposed revisions and has concurred with above determinations.
In accordance with 10CFR50.91(b), we are providing the State of Connecticut with a copy of these proposed amendments.
Although the license amendment request proposed herein is not directly related to the refueling outage curren'tly underway, NNECO requests that if approved, the NRC Staff issue the license amendment by December 9,1986, to support startup from the refueling outage. This amendment may be required at that time to address potential steam generator tube plugging and sleeving conducted during the outage, the precise scope of which is unknown at this time.
Pursuant to the requirements of 10CFR170.12(c), enclosed with this amendment request is the application fee of $150.
Very truly yours, NORTHEAST NUCLEAR ENERGY COMPANY bEAA J. F. Opeka Senior Vice President l
l By: R. W. Bishop Secretary                                       I cc:   Kevin McCarthy Director, Radiation Control Unit Department of Environmental Protection Hartford, Connecticut 06116

   = . . .
v STATE OF CONNECTICUT )
                                      .                                            ) ss. Berlin
!                               COUNTY OF HARTFORD                                 )
                                                                ~
Then personally appeared before me R. W. Bishop, who being duly sworn, did state that he is Secretary of Northeast Nuclear Energy Company, a Licensee herein, that he is authorized to execute and file the foregoing information in the
:                               name and on behalf of the Licensees herein and that the statements contained in
]                               said information are true and correct to the best of his knowledge and belief.
j                                                                                                                                -
Notary Pubig '
i MY COMMISSION EXPIRES MARCH 31,1991 1
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