ML18068A300: Difference between revisions
StriderTol (talk | contribs) (Created page by program invented by StriderTol) |
StriderTol (talk | contribs) (Created page by program invented by StriderTol) |
||
Line 14: | Line 14: | ||
| page count = 7 | | page count = 7 | ||
}} | }} | ||
=Text= | =Text= | ||
{{#Wiki_filter:.. !' '* . * * Consumers | {{#Wiki_filter:.. !' '* . * | ||
Energy> A CMS Energy Company February 27, 1998 U.S. Nuclear Regulatory | * Consumers Energy> A CMS Energy Company February 27, 1998 U.S. Nuclear Regulatory Commission ATIN: Document Control Desk Washington, DC 20555 Palisades Nuclear Plant 27780 Blue Star Memorial Highway Covert, Ml 49043 DOCKET 50-255 -LICENSE DPR-20 -PALISADES PLANT Da11/d llt Rogers General Manager -Plant Operations REPLY TO NOTICE OF VIOLATION DESCRIBED IN INSPECTION REPORT NO. 50-255/97013 NRC Inspection Report No. 50-255/97013 dated January 21, 1998, contains a Notice of Violation (NOV) concerning an inadequate procedure which allowed operators to start a primary coolant pump without meeting Technical Specification requirements. | ||
Commission | The Consumers Energy Company reply to the violation is included in the Attachment to this letter. The reply to the violation was requested to be submitted within 30 days from the date of the letter transmitting the violation. | ||
ATIN: Document Control Desk Washington, DC 20555 Palisades | Discussion with Bruce Burgess (NRC Region Ill) on January 28, 1998, confirmed that the 30-day requested response could be provided | ||
Nuclear Plant 27780 Blue Star Memorial Highway Covert, Ml 49043 DOCKET 50-255 -LICENSE DPR-20 -PALISADES | * within 30 days of receipt of the letter, which was January 28, 1998. Consumers Energy Company agrees with the violation as written. An additional concern regarding the Technical Specification aspects of the event and the lack of a questioning attitude by the operators was expressed in the cover letter for the repor:t. Jha_t concern will be addressed in more detail in a separate submittal. | ||
PLANT Da11/d llt Rogers General Manager -Plant Operations | 9803060419 980227 PDR ADOCK 05000255 G PDR 1111111111111111111111111111111111111111 | ||
REPLY TO NOTICE OF VIOLATION | |||
DESCRIBED | |||
IN INSPECTION | |||
REPORT NO. 50-255/97013 | |||
NRC Inspection | |||
Report No. 50-255/97013 | |||
dated January 21, 1998, contains a Notice of Violation (NOV) concerning | |||
an inadequate | |||
procedure | |||
which allowed operators | |||
to start a primary coolant pump without meeting Technical | |||
Specification | |||
requirements. | |||
The Consumers | |||
Energy Company reply to the violation | |||
is included in the Attachment | |||
to this letter. The reply to the violation | |||
was requested | |||
to be submitted | |||
within 30 days from the date of the letter transmitting | |||
the violation. | |||
Discussion | |||
with Bruce Burgess (NRC Region Ill) on January 28, 1998, confirmed | |||
that the 30-day requested | |||
response could be provided * within 30 days of receipt of the letter, which was January | |||
28, 1998. Consumers | |||
Energy Company agrees with the violation | |||
as written. An additional | |||
concern regarding | |||
the Technical | |||
Specification | |||
aspects of the event and the lack of a questioning | |||
attitude by the operators | |||
was expressed | |||
in the cover letter for the | |||
repor:t. Jha_t concern will be addressed | |||
in more detail in a separate submittal. | |||
9803060419 | |||
980227 PDR ADOCK 05000255 G PDR 1111111111111111111111111111111111111111 | |||
*&&8E37* l l ' I . I , . ! f | *&&8E37* l l ' I . I , . ! f | ||
*. * SUMMARY OF COMMITMENTS | *. * | ||
This letter contains one commitment. | |||
This commitment | ==SUMMARY== | ||
is a restatement | OF COMMITMENTS This letter contains one commitment. | ||
of the . commitment | This commitment is a restatement of the . commitment made previously in Licensee Event Report 97-011, submitted on November 11 , 1997. That commitment is: | ||
made previously | * System Operating Procedure SOP-1 will be revised to clarify requirements for starting primary coolant pumps when the PCS is solid. This revision will be made prior to the next use of the procedure for this purpose. David W. Rogers Plant General Manager CC Administrator, Region Ill, USNRC Project Manager, NRR, USNRC NRC Resident Inspector | ||
in Licensee Event Report 97-011, submitted | -Palisades Attachment 2 | ||
on November 11 , 1997. That commitment | * . -ATTACHMENT CONSUMERS ENERGY COMPANY PALISADES PLANT DOCKET 50-255 REPLY TO NOTICE OF VIOLATION NO. 50-255/97013-01 (DRP) 4 Pages | ||
is: * System Operating | * ATTACHMENT REPLY TO NOTICE OF VIOLATION NO. 50-255/97013-01 (DRP) NRC NOTICE OF VIOLATION During an NRG inspection from October 18 through December 5, 1997, one violation of NRG requirements was identified. | ||
Procedure | In accordance with the "General Statement of Policy and Procedure for NRG Enforcement Actions", NUREG 1600, the violation is listed below: 10 CFR Part 50, Appendix 8, Criterion V, "Instructions, Procedures, and Drawings," requires, in part, that activities affecting quality shall be prescribed by documented instructions, procedures, or drawings of a type appropriate to the circumstances and shall be accomplished in accordance with these instructions, procedures, or drawings. | ||
SOP-1 will be revised to clarify requirements | Contrary to the above, on October 12, 1997, the operations shift started the first primary coolant pump, using System Operating Procedure (SOP)-1, Revision 38, Step 4.3.1.(c)2, a procedure inappropriate to the circumstances in that it allowed using shutdown cooling return temperature (when shutdown cooling is operating), instead of T ccld* which resulted in the operators exceeding the Technical Specifications T cold primary coolant pump start temperature limits. This is a Severity Level IV violation (Supplement/). | ||
for starting primary coolant pumps when the PCS is solid. This revision will be made prior to the next use of the procedure | CONSUMERS ENERGY COMPANY RESPONSE Consumers Energy agrees with this violation as 'written. | ||
for this purpose. David W. Rogers Plant General Manager CC Administrator, Region Ill, USNRC Project Manager, NRR, USNRC NRC Resident Inspector | Background On October 12 1997, plant heatup from a short maintenance outage was in progress. | ||
-Palisades | At approximately 1926 hours, with the plant at 250 psia and 130°F, plant prerequisites and checklists had been completed and Primary Coolant Pump (PCP) P-500 was started. Immediately following the pump start, the Primary Coolant System (PCS) pressure started to rise. Anticipating the PCS pressure rise, operators took manual action and limited the pressure to approximately 280 psia. A Low Temperature Overpressure Protection (L TOP) actuation did not occur since the L TOP setpoint at the prevailing PCS temperature was approximately 31 O psia. Because PCS pressure rose to this extent in a solid PCS, it was apparent that heat had been transferred from the steam generator secondary into the PCS, and that Technical Specification 3.1.1.h(2) 1 | ||
Attachment | ** ATTACHMENT REPLY TO NOTICE OF VIOLATION NO. 50-255/97013-01 (DRP) had been violated. | ||
2 | Technical Specification 3.1.1.h(2) requires that forced circulation (starting of the first primary coolant pump) shall not be initiated unless " ... the steam generator secondary temperature is less than or equal to T cold,'' to prevent an overpressurization of the PCS. The magnitude of the PCS pressure rise following start of the pump shows that the steam generator secondary bulk fluid temperature could not have been less than T cold* The steam generators do not have an installed temperature indicator which can accurately indicate secondary fluid temperature. | ||
* . -ATTACHMENT | One method to obtain steam generator secondary side temperature to verify compliance with Technical Specifications is to obtain a contact temperature reading from a secondary handhole cover. While normally adequate, the temperature provided by this method can differ from the bulk average temperature if the secondary side fluid is not adequately mixed. In this event, the temperature measurement obtained by the operators was not representative of the bulk temperature due to stratification. | ||
CONSUMERS | * A similar limitation exists in the measurement of primary coolant temperature when the PCS is on shutdown cooling. Normal T cold indications could be slightly higher than the coldest temperature which may exist in the PCS because shutdown cooling flow does not provide complete mixing in the PCS loops. When primary coolant and shutdown cooling system temperatures are stable, the shutdown cooling return temperature is typically cooler than indicated primary coolant temperatures. | ||
ENERGY COMPANY PALISADES | Use of this temperature as a lower bound value of T cold is normally viewed as more reliable and conservative than direct T cold indication. | ||
PLANT DOCKET 50-255 REPLY TO NOTICE OF VIOLATION | There are times, however, including during this event, when shutdown cooling return temperature is higher than T cold* | ||
NO. 50-255/97013-01 (DRP) 4 Pages | * Operating Procedure SOP-1 does not adequately account for the temperature measurement limitations inherent in the plant design, can be construed to permit use of shutdown cooling return temperature instead ofT cold to verify compliance with Technical Specifications. | ||
* ATTACHMENT | The inadequacy of this procedure was the primary cause for the event. The situation was aggravated, however, because of inadequate questioning by the operating crew. The crew failed to question the significance of T cold being lower than the shutdown cooling return temperature, and lower than the steam generator hand hole cover contacttemperature; they failed to question the apparent conflict between the procedure's use of shutdown cooling return temperature and the specific wording of the Technical Specifications restriction on pump starting; and they failed to consider 2 CJ | ||
REPLY TO NOTICE OF VIOLATION | * ATTACHMENT REPLY TO NOTICE OF VIOLATION NO. 50-255/97013-01 (DRP) uncertainty that may exist in the steam generator secondary fluid temperature as measured at the handhole cover. This event was reported to the NRC in Licensee Event Report 97-011, dated November 11, 1997. Reasons for Violation The root causes of this violation are as follows. 1. System Operating Procedure SOP-1 was inadequate. | ||
NO. 50-255/97013-01 (DRP) NRC NOTICE OF VIOLATION | The procedure did not adequately account for the temperature measurement limitations inherent in the plant design, and can be construed to permit use of shutdown cooling return temperature instead of T cold to verify compliance with Technical Specifications. | ||
During an NRG inspection | : 2. Inadequate questioning by the operating crew contributed to the event. The crew failed to challenge the apparent inconsistencies between the procedure and Techni.cal Specifications, and failed to question the accuracy of their temperature indications. | ||
from October 18 through December 5, 1997, one violation | Corrective Action Taken and Results Achieved The following corrective actions have been taken: 1. The Operations Superintendent conducted a critique of this event with licensed operators involved. | ||
of NRG requirements | The emphasis was on compliance with Technical Specifications and making conservative decisions with respect to Technical Specification limits. | ||
was identified. | * 2. Training on the effects of stratification in the steam generators on PCS temperature was provided to licensed operators. | ||
In accordance | This included the effects when the PCPs are started and also the effects when the steam generators are placed on recirculation or bubbled with Nitrogen. | ||
with the "General Statement | : 3. The Operations Superintendent discussed this event with the operating crews from the standpoint of making conservative decisions when 3 | ||
of Policy and Procedure | .. ,,. | ||
for NRG Enforcement | * ATTACHMENT REPLY TO NOTICE OF VIOLATION NO. 50-255/97013-01 (DRP) operating the Plant with respect to Technical Specification limits or | ||
Actions", NUREG 1600, the violation | * procedural limits. This included lessons learned and advocacy and questioning attitude by all members of the operating shift. These actions have raised the sensitivity of the operating staff to the need for conservative decisions and questioning of apparent procedure inconsistencies. | ||
is listed below: 10 CFR Part 50, Appendix 8, Criterion | In addition: | ||
V, "Instructions, Procedures, and Drawings," requires, in part, that activities | : 4. Strategies for primary coolant pump starting have been reviewed to identify necessary procedure clarifications. | ||
affecting | Corrective Actions Remaining to Avoid Further Violations System Operating Procedure SOP-1 will be revised to clarify requirements for starting primary coolant pumps when the PCS is solid. This revision will be made prior to the next use of the procedure for this purpose. Date Full Compliance Will Be Achieved Full compliance will be achieved when System Operating Procedure SOP-1 is revised to provide better guidance for starting primary coolant pumps, 4}} | ||
quality shall be prescribed | |||
by documented | |||
instructions, procedures, or drawings of a type appropriate | |||
to the circumstances | |||
and shall be accomplished | |||
in accordance | |||
with these instructions, procedures, or drawings. | |||
Contrary to the above, on October 12, 1997, the operations | |||
shift started the first primary coolant pump, using System Operating | |||
Procedure (SOP)-1, Revision 38, Step 4.3.1.(c)2, a procedure | |||
inappropriate | |||
to the circumstances | |||
in that it allowed using shutdown cooling return temperature (when shutdown cooling is operating), instead of T ccld* which resulted in the operators | |||
exceeding | |||
the Technical | |||
Specifications | |||
T cold primary coolant pump start temperature | |||
limits. This is a Severity Level IV violation (Supplement/). | |||
CONSUMERS | |||
ENERGY COMPANY RESPONSE Consumers | |||
Energy agrees with this violation | |||
as 'written. | |||
Background | |||
On October 12 1997, plant heatup from a short maintenance | |||
outage was in progress. | |||
At approximately | |||
1926 hours, with the plant at 250 psia and 130°F, plant prerequisites | |||
and checklists | |||
had been completed | |||
and Primary Coolant Pump (PCP) P-500 was started. Immediately | |||
following | |||
the pump start, the Primary Coolant System (PCS) pressure started to rise. Anticipating | |||
the PCS pressure rise, operators | |||
took manual action and limited the pressure to approximately | |||
280 psia. A Low Temperature | |||
Overpressure | |||
Protection (L TOP) actuation | |||
did not occur since the L TOP setpoint at the prevailing | |||
PCS temperature | |||
was approximately | |||
31 O psia. Because PCS pressure rose to this extent in a solid PCS, it was apparent that heat had been transferred | |||
from the steam generator | |||
secondary | |||
into the PCS, and that Technical | |||
Specification | |||
3.1.1.h(2) | |||
1 | |||
** ATTACHMENT | |||
REPLY TO NOTICE OF VIOLATION | |||
NO. 50-255/97013-01 (DRP) had been violated. | |||
Technical | |||
Specification | |||
3.1.1.h(2) | |||
requires that forced circulation (starting | |||
of the first primary coolant pump) shall not be initiated | |||
unless " ... the steam generator | |||
secondary | |||
temperature | |||
is less than or equal to T cold,'' to prevent an overpressurization | |||
of the PCS. The magnitude | |||
of the PCS pressure rise following | |||
start of the pump shows that the steam | |||
generator | |||
secondary | |||
bulk fluid temperature | |||
could not have been less than T cold* The steam generators | |||
do not have an installed | |||
temperature | |||
indicator | |||
which can accurately | |||
indicate secondary | |||
fluid temperature. | |||
One method to obtain steam generator | |||
secondary | |||
side temperature | |||
to verify compliance | |||
with Technical | |||
Specifications | |||
is to obtain a contact temperature | |||
reading from a secondary | |||
handhole cover. While normally adequate, the temperature | |||
provided by this method can differ from the bulk average temperature | |||
if the secondary | |||
side fluid is not adequately | |||
mixed. In this event, the temperature | |||
measurement | |||
obtained by the operators | |||
was not representative | |||
of the bulk temperature | |||
due to stratification. | |||
* A similar limitation | |||
exists in the measurement | |||
of primary coolant temperature | |||
when the PCS is on shutdown cooling. Normal T cold indications | |||
could be slightly higher than the coldest temperature | |||
which may exist in the PCS because shutdown cooling flow does not provide complete mixing in the PCS loops. When primary coolant and shutdown cooling system temperatures | |||
are stable, the shutdown cooling return temperature | |||
is typically | |||
cooler than indicated | |||
primary coolant temperatures. | |||
Use of this temperature | |||
as a lower bound value of T cold is normally viewed as more reliable and conservative | |||
than direct T cold indication. | |||
There are times, however, including | |||
during this event, when shutdown cooling return temperature | |||
is higher than T cold* * Operating | |||
Procedure | |||
SOP-1 does not adequately | |||
account for the temperature | |||
measurement | |||
limitations | |||
inherent in the plant design, can be construed | |||
to permit use of shutdown cooling return temperature | |||
instead ofT cold to verify compliance | |||
with Technical | |||
Specifications. | |||
The inadequacy | |||
of this procedure | |||
was the primary cause for the event. The situation | |||
was aggravated, however, because of inadequate | |||
questioning | |||
by the operating | |||
crew. The crew failed to question the significance | |||
of T cold being lower than the shutdown cooling return temperature, and lower than the steam generator | |||
hand hole cover contacttemperature; | |||
they failed to question the apparent conflict between the procedure's | |||
use of shutdown cooling return temperature | |||
and the specific wording of the Technical | |||
Specifications | |||
restriction | |||
on pump starting; | |||
and they failed to consider 2 | |||
REPLY TO NOTICE OF VIOLATION | |||
NO. 50-255/97013-01 (DRP) uncertainty | |||
that may exist in the steam generator | |||
secondary | |||
fluid temperature | |||
as measured at the handhole cover. This event was reported to the NRC in Licensee Event Report 97-011, dated November 11, 1997. Reasons for Violation | |||
The root causes of this violation | |||
are as follows. 1. System Operating | |||
Procedure | |||
SOP-1 was inadequate. | |||
The procedure | |||
did not adequately | |||
account for the temperature | |||
measurement | |||
limitations | |||
inherent in the plant design, and can be construed | |||
to permit use of shutdown cooling return temperature | |||
instead of T cold to verify compliance | |||
with Technical | |||
Specifications. | |||
2. Inadequate | |||
questioning | |||
by the operating | |||
crew contributed | |||
to the event. The crew failed to challenge | |||
the apparent inconsistencies | |||
between the procedure | |||
and Techni.cal | |||
Specifications, and failed to question the accuracy of their temperature | |||
indications. | |||
Corrective | |||
Action Taken and Results Achieved The following | |||
corrective | |||
actions have been taken: 1. The Operations | |||
Superintendent | |||
conducted | |||
a critique of this event with licensed operators | |||
involved. | |||
The emphasis was on compliance | |||
with Technical | |||
Specifications | |||
and making conservative | |||
decisions | |||
with respect to Technical | |||
Specification | |||
limits. * 2. Training on the effects of stratification | |||
in the steam generators | |||
on PCS temperature | |||
was provided to licensed operators. | |||
This included the effects when the PCPs are started and also the effects when the steam generators | |||
are placed on recirculation | |||
or bubbled with Nitrogen. | |||
3. The Operations | |||
Superintendent | |||
discussed | |||
this event with the operating | |||
crews from the standpoint | |||
of making conservative | |||
decisions | |||
when 3 | |||
.. ,,. * ATTACHMENT | |||
REPLY TO NOTICE OF VIOLATION | |||
NO. 50-255/97013-01 (DRP) operating | |||
the Plant with respect to Technical | |||
Specification | |||
limits or * procedural | |||
limits. This included lessons learned and advocacy and questioning | |||
attitude by all members of the operating | |||
shift. These actions have raised the sensitivity | |||
of the operating | |||
staff to the need for conservative | |||
decisions | |||
and questioning | |||
of apparent procedure | |||
inconsistencies. | |||
In addition: | |||
4. Strategies | |||
for primary coolant pump starting have been reviewed to identify necessary | |||
procedure | |||
clarifications. | |||
Corrective | |||
Actions Remaining | |||
to Avoid Further Violations | |||
System Operating | |||
Procedure | |||
SOP-1 will be revised to clarify requirements | |||
for starting primary coolant pumps when the PCS is solid. This revision will be made prior to the next use of the procedure | |||
for this purpose. Date Full Compliance | |||
Will Be Achieved Full compliance | |||
will be achieved when System Operating | |||
Procedure | |||
SOP-1 is revised to provide better guidance for starting primary coolant pumps, 4 | |||
}} |
Revision as of 22:55, 31 July 2019
ML18068A300 | |
Person / Time | |
---|---|
Site: | Palisades ![]() |
Issue date: | 02/27/1998 |
From: | Rogers D CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
References | |
50-255-97-13, NUDOCS 9803060419 | |
Download: ML18068A300 (7) | |
Text
.. !' '* . *
- Consumers Energy> A CMS Energy Company February 27, 1998 U.S. Nuclear Regulatory Commission ATIN: Document Control Desk Washington, DC 20555 Palisades Nuclear Plant 27780 Blue Star Memorial Highway Covert, Ml 49043 DOCKET 50-255 -LICENSE DPR-20 -PALISADES PLANT Da11/d llt Rogers General Manager -Plant Operations REPLY TO NOTICE OF VIOLATION DESCRIBED IN INSPECTION REPORT NO. 50-255/97013 NRC Inspection Report No. 50-255/97013 dated January 21, 1998, contains a Notice of Violation (NOV) concerning an inadequate procedure which allowed operators to start a primary coolant pump without meeting Technical Specification requirements.
The Consumers Energy Company reply to the violation is included in the Attachment to this letter. The reply to the violation was requested to be submitted within 30 days from the date of the letter transmitting the violation.
Discussion with Bruce Burgess (NRC Region Ill) on January 28, 1998, confirmed that the 30-day requested response could be provided
- within 30 days of receipt of the letter, which was January 28, 1998. Consumers Energy Company agrees with the violation as written. An additional concern regarding the Technical Specification aspects of the event and the lack of a questioning attitude by the operators was expressed in the cover letter for the repor:t. Jha_t concern will be addressed in more detail in a separate submittal.
9803060419 980227 PDR ADOCK 05000255 G PDR 1111111111111111111111111111111111111111
- &&8E37* l l ' I . I , . ! f
- . *
SUMMARY
OF COMMITMENTS This letter contains one commitment.
This commitment is a restatement of the . commitment made previously in Licensee Event Report 97-011, submitted on November 11 , 1997. That commitment is:
- System Operating Procedure SOP-1 will be revised to clarify requirements for starting primary coolant pumps when the PCS is solid. This revision will be made prior to the next use of the procedure for this purpose. David W. Rogers Plant General Manager CC Administrator, Region Ill, USNRC Project Manager, NRR, USNRC NRC Resident Inspector
-Palisades Attachment 2
- . -ATTACHMENT CONSUMERS ENERGY COMPANY PALISADES PLANT DOCKET 50-255 REPLY TO NOTICE OF VIOLATION NO. 50-255/97013-01 (DRP) 4 Pages
- ATTACHMENT REPLY TO NOTICE OF VIOLATION NO. 50-255/97013-01 (DRP) NRC NOTICE OF VIOLATION During an NRG inspection from October 18 through December 5, 1997, one violation of NRG requirements was identified.
In accordance with the "General Statement of Policy and Procedure for NRG Enforcement Actions", NUREG 1600, the violation is listed below: 10 CFR Part 50, Appendix 8, Criterion V, "Instructions, Procedures, and Drawings," requires, in part, that activities affecting quality shall be prescribed by documented instructions, procedures, or drawings of a type appropriate to the circumstances and shall be accomplished in accordance with these instructions, procedures, or drawings.
Contrary to the above, on October 12, 1997, the operations shift started the first primary coolant pump, using System Operating Procedure (SOP)-1, Revision 38, Step 4.3.1.(c)2, a procedure inappropriate to the circumstances in that it allowed using shutdown cooling return temperature (when shutdown cooling is operating), instead of T ccld* which resulted in the operators exceeding the Technical Specifications T cold primary coolant pump start temperature limits. This is a Severity Level IV violation (Supplement/).
CONSUMERS ENERGY COMPANY RESPONSE Consumers Energy agrees with this violation as 'written.
Background On October 12 1997, plant heatup from a short maintenance outage was in progress.
At approximately 1926 hours0.0223 days <br />0.535 hours <br />0.00318 weeks <br />7.32843e-4 months <br />, with the plant at 250 psia and 130°F, plant prerequisites and checklists had been completed and Primary Coolant Pump (PCP) P-500 was started. Immediately following the pump start, the Primary Coolant System (PCS) pressure started to rise. Anticipating the PCS pressure rise, operators took manual action and limited the pressure to approximately 280 psia. A Low Temperature Overpressure Protection (L TOP) actuation did not occur since the L TOP setpoint at the prevailing PCS temperature was approximately 31 O psia. Because PCS pressure rose to this extent in a solid PCS, it was apparent that heat had been transferred from the steam generator secondary into the PCS, and that Technical Specification 3.1.1.h(2) 1
- ATTACHMENT REPLY TO NOTICE OF VIOLATION NO. 50-255/97013-01 (DRP) had been violated.
Technical Specification 3.1.1.h(2) requires that forced circulation (starting of the first primary coolant pump) shall not be initiated unless " ... the steam generator secondary temperature is less than or equal to T cold, to prevent an overpressurization of the PCS. The magnitude of the PCS pressure rise following start of the pump shows that the steam generator secondary bulk fluid temperature could not have been less than T cold* The steam generators do not have an installed temperature indicator which can accurately indicate secondary fluid temperature.
One method to obtain steam generator secondary side temperature to verify compliance with Technical Specifications is to obtain a contact temperature reading from a secondary handhole cover. While normally adequate, the temperature provided by this method can differ from the bulk average temperature if the secondary side fluid is not adequately mixed. In this event, the temperature measurement obtained by the operators was not representative of the bulk temperature due to stratification.
- A similar limitation exists in the measurement of primary coolant temperature when the PCS is on shutdown cooling. Normal T cold indications could be slightly higher than the coldest temperature which may exist in the PCS because shutdown cooling flow does not provide complete mixing in the PCS loops. When primary coolant and shutdown cooling system temperatures are stable, the shutdown cooling return temperature is typically cooler than indicated primary coolant temperatures.
Use of this temperature as a lower bound value of T cold is normally viewed as more reliable and conservative than direct T cold indication.
There are times, however, including during this event, when shutdown cooling return temperature is higher than T cold*
- Operating Procedure SOP-1 does not adequately account for the temperature measurement limitations inherent in the plant design, can be construed to permit use of shutdown cooling return temperature instead ofT cold to verify compliance with Technical Specifications.
The inadequacy of this procedure was the primary cause for the event. The situation was aggravated, however, because of inadequate questioning by the operating crew. The crew failed to question the significance of T cold being lower than the shutdown cooling return temperature, and lower than the steam generator hand hole cover contacttemperature; they failed to question the apparent conflict between the procedure's use of shutdown cooling return temperature and the specific wording of the Technical Specifications restriction on pump starting; and they failed to consider 2 CJ
- ATTACHMENT REPLY TO NOTICE OF VIOLATION NO. 50-255/97013-01 (DRP) uncertainty that may exist in the steam generator secondary fluid temperature as measured at the handhole cover. This event was reported to the NRC in Licensee Event Report 97-011, dated November 11, 1997. Reasons for Violation The root causes of this violation are as follows. 1. System Operating Procedure SOP-1 was inadequate.
The procedure did not adequately account for the temperature measurement limitations inherent in the plant design, and can be construed to permit use of shutdown cooling return temperature instead of T cold to verify compliance with Technical Specifications.
- 2. Inadequate questioning by the operating crew contributed to the event. The crew failed to challenge the apparent inconsistencies between the procedure and Techni.cal Specifications, and failed to question the accuracy of their temperature indications.
Corrective Action Taken and Results Achieved The following corrective actions have been taken: 1. The Operations Superintendent conducted a critique of this event with licensed operators involved.
The emphasis was on compliance with Technical Specifications and making conservative decisions with respect to Technical Specification limits.
- 2. Training on the effects of stratification in the steam generators on PCS temperature was provided to licensed operators.
This included the effects when the PCPs are started and also the effects when the steam generators are placed on recirculation or bubbled with Nitrogen.
- 3. The Operations Superintendent discussed this event with the operating crews from the standpoint of making conservative decisions when 3
.. ,,.
- ATTACHMENT REPLY TO NOTICE OF VIOLATION NO. 50-255/97013-01 (DRP) operating the Plant with respect to Technical Specification limits or
- procedural limits. This included lessons learned and advocacy and questioning attitude by all members of the operating shift. These actions have raised the sensitivity of the operating staff to the need for conservative decisions and questioning of apparent procedure inconsistencies.
In addition:
- 4. Strategies for primary coolant pump starting have been reviewed to identify necessary procedure clarifications.
Corrective Actions Remaining to Avoid Further Violations System Operating Procedure SOP-1 will be revised to clarify requirements for starting primary coolant pumps when the PCS is solid. This revision will be made prior to the next use of the procedure for this purpose. Date Full Compliance Will Be Achieved Full compliance will be achieved when System Operating Procedure SOP-1 is revised to provide better guidance for starting primary coolant pumps, 4