NOED-00-6-006 - Waterford 3 (Entergy Operations, Inc.)
May 1, 2000
Mr. Charles M. Dugger
Vice President Operations
Entergy Operations, Inc.
17265 River Road
Killona, LA 70066-0751
||NOTICE OF ENFORCEMENT DISCRETION FOR ENTERGY OPERATIONS, INC. REGARDING
WATERFORD STEAM ELECTRIC STATION, UNIT 3 (NOED NO. 00-6-006)
Dear Mr. Dugger:
By letter dated April 27, 2000, you requested that the Nuclear Regulatory
Commission (NRC) exercise discretion not to enforce compliance with the
actions required in the Technical Specification (TS) 22.214.171.124 Limiting
Condition for Operation (LCO). Your letter documented information previously
discussed with the NRC in a telephone conference on April 26, 2000, at
9:00 a.m. The principal NRC staff members who participated in that telephone
conference included, among others, Mr. S. Richards, Project Director,
Mr. R. Gramm, Section Chief, and Mr. G. Hubbard, Section Chief, all from
NRC Headquarters; Mr. K. Brockman, Division Director and Mr. D. Proulx,
Acting Branch Chief, from Region IV; and Mr. T. Farnholtz, the Senior
Resident Inspector at Waterford Steam Electric Station, Unit 3 (Waterford
3). You stated that as of April 24, 2000, at 10:16 p.m., Waterford 3 did
not meet the LCO for TS 126.96.36.199, which requires two trains of Containment
Fan Coolers (CFC) be OPERABLE, with two fan coolers in each train in Modes
1 through 4. With one train inoperable, the inoperable train must be restored
to an operable status within 72 hours (April 27, 2000 at 10:16 p.m) or
the plant must be in HOT STANDBY within the next six hours.
You requested that a Notice of Enforcement Discretion (NOED) be issued
pursuant to the NRC's policy regarding exercise of discretion for an operating
facility, set out in Section VII.c, of the "General Statement of Policy
and Procedures for NRC Enforcement Actions" (Enforcement Policy), NUREG-1600,
and be effective for the period until Waterford 3 Technical Specification
Change Request NPF-38-224 is approved or an outage of sufficient duration
occurs to accommodate repair of the containment fan cooler. This letter
documents our telephone conversation on April 27, 2000, at 3:45 p.m. when
we orally issued the NOED.
The CFC system consists of four fan coolers which draw air from containment
and discharge it to a ring header around the top of containment. The CFC
system coolers are divided into two trains - Train A, which contains CFCs
"A" and "C," and Train B, which contains CFCs "B" and "D." On April 24,
2000, at 10:16 p.m., CFC "C" tripped following vibration alarms. CFC "C"
was declared inoperable and the Action Statement for TS 188.8.131.52 was entered.
A containment entry was performed at 02:37 a.m. on April 25, 2000, to
visually inspect CFC "C" and the following conditions were noted:
- Hot spots (paint discoloration) were identified at the 2 o'clock and
4 o'clock to 7 o'clock positions where it appeared the fan blades had
rubbed against the shroud.
- The edges of the fan blades appeared to be worn or melted.
- Lubricant was noted to have leaked out of the motor outboard bearing.
- The motor/fan base plate bolts could be turned using a wrench.
- The fan could not be turned by hand due to restrictions caused by
the blades rubbing on the shroud.
After a second containment entry to perform a more detailed inspection
of CFC "C," it was determined that an on-line repair was not feasible
within the 72 hour LCO Action Statement Allowed Outage Time. You requested
enforcement discretion to allow plant operation to continue with one operable
fan cooler per train.
NRC Inspection Manual, Part 9900, Notice of Enforcement Discretion, Section
C.4 requires that the request for NOED address the following 11 items,
as appropriate. In your letter dated April 27, 2000, you provided the
The TS or other license conditions that will be violated.
The LCO for TS 184.108.40.206, "Containment Cooling System" requires the
"Two independent trains of containment cooling shall be OPERABLE
with two fan coolers to each train."
The circumstances surrounding the situation, including root causes,
the need for prompt action, and identification of any relevant historical
Following the trip, electricians meggered the motor and checked
phase to phase resistances. These checks were all found to be satisfactory.
The containment entry performed at 02:37 a.m. on April 25, 2000, noted
that the fan blades on CFC "C" appeared to have rubbed against the
shroud, the edges of the fan blades appeared to be worn or melted,
lubricant was noted to have leaked out of the motor outboard bearing,
and the fan could not be turned by hand because the fan blades were
rubbing the shroud.
The other three CFCs were inspected and tested to provide added
assurance that a similar condition did not exist. Specifically, the
motor diagnostic testing and vibration diagnostics, including external
inspection, were done on CFCs "A," "B," and "D." In addition, an internal
visual inspection was performed on CFC "A." The results of the eccentricity
spectrum for each motor showed no signs of eccentricity problems.
The vibration readings taken on the housing of the vane axial fan
(readings could not be taken from the bearing casing directly, since
the bearing casing is inaccessible) lead to the conclusion that the
CFCs were operating in the good range in regards to vibration. There
were no unusual audible noises nor were abnormalities observed. The
results of the internal visual inspection of CFC "A" indicate that
the fan is in good condition with no evidence of a bearing problem,
the fan rotated freely with adequate clearance between the fan blades
and shroud, and all the hardware appeared to be firmly in place with
no free play detected in the bearing.
The preventive maintenance work history on CFC "C" has been reviewed.
During refueling outage 9, the motor was lubricated, routine motor
maintenance was performed, and the vibration survey was satisfactory.
The failure of the CFC "C" motor bearings could have been caused by
either misalignment of motor/fan assembly with housing as a result
of failed mounting rods or a lubrication fault. The root cause will
be determined as a part of the Corrective Action Program when the
licensee removes CFC "C" from the containment and performs a motor
tear down. The licensee will also assess industry bearing failure
data as part of its root cause analysis.
The safety basis for the request, including an evaluation of the
safety significance and potential consequences of the proposed course
of action. This evaluation should include at least a qualitative risk
assessment derived from the licensee's probabilistic risk analysis
A safety evaluation for operating the plant with one CFC per train
is based on containment pressure and temperature response analyses
performed for the limiting large break Loss of Coolant Accidents (LOCA)
and limiting Main Steam Line Break (MSLB) events using the GOTHIC
computer code. These analyses have been submitted to NRC for approval
in TS Change Request NPF-38-224. Several LOCA and MSLB events are
analyzed using GOTHIC and the Waterford 3 containment model to determine
the limiting cases for:
- LOCA containment peak pressure
- Post-LOCA containment pressure at 24 hours
- MSLB peak containment pressure
- MSLB peak containment temperature
The limiting LOCA for containment peak pressure was determined to
be the double ended hot leg slot break. The peak pressure for the
hot leg break occurs near the end of the blowdown phase, which is
prior to the start of safety injection flow, start of CFC operation,
and start of containment spray flow into the containment. The calculated
peak containment pressure was 35.2 psig, which is well below the containment
design pressure of 44 psig. The current Updated Final Safety Analysis
Report (UFSAR) Chapter 15 analysis had determined that the double
ended suction leg slot break with minimum safety injection flow assumption
was the limiting LOCA for containment peak pressure with pressure
of 43.1 psig that occurs during reflood. The difference between the
new and old results is due primarily to the new mass and energy data,
which shows a lower mass and energy into containment during the reflood
time period. The limiting LOCA for containment pressure at 24 hours
was determined to be the double ended discharge leg slot break with
minimum safety injection flow assumption. The peak containment pressure
for this case was calculated to be 33.27 psig. Thus, the containment
pressure at 24 hours must be reduced to less than half the containment
peak pressure or 16.64 psig. The containment pressure at 24 hours
was calculated to be 15.5 psig, which is less than half the associated
containment peak pressure. Thismeets Acceptance Criteria II, Section
b in the Standard Review Plan 220.127.116.11.A, "PWR Dry Containments, Including
The limiting MSLB event for containment peak pressure was determined
to be a MSLB from 102 percent power with failure of one containment
heat removal train consisting of one containment spray (CS) pump and
one CFC operable. The calculated peak containment pressure was 42.68
psig, which is below the containment design pressure of 44 psig. The
current UFSAR licensing analysis determined that the limiting MSLB
event was a MSLB from 75 percent power with the failure of one train
of containment heat removal system consisting of one CS train and
two operable CFCs with a peak pressure of 42.9 psig. The limiting
event for containment peak temperature was determined to be a MSLB
from 102 percent power with failure of one main steam isolation valve
to close. The calculated peak containment temperature was 397.4 °F,
which is less than the current maximum allowed temperature of 413.5
In the Waterford 3 PRA model, CFCs provide cooling for the containment
to prevent a long term overpressurization failure. Analyses were done
to show that one fan cooler or one CS train was adequate to remove
sufficient heat to prevent containment overpressure failure. The impact
on containment failure probability due to one CFC being inoperable
is negligible. The probability of failure for all containment cooling
(both spray trains and all fan coolers) was calculated to be 1.9E-4.
This is dominated by failures of common support systems, such as electrical
power or component cooling water. These support system failures are
not affected by the inoperability of one CFC. Cutsets with individual
CFC failures that would be affected are below 1E-9 and therefore have
only a negligible impact on containment failure probability. The impact
of CFC failures on the core damage frequency during a LOCA (containment
overpressurization failure resulting in rapid depressurization of
the containment and cavitation of the operating safety injection recirculation)
is extremely low, about 1E-11, and is also negligible.
The basis for the licensee's conclusion that the noncompliance will
not be of potential detriment to the public health and safety and
that neither an unreviewed safety question nor a significant hazard
consideration is involved.
The proposed change reduces the number of CFCs from two to one required
to be operable in each train of the containment cooling system (CCS)
for Modes 1, 2, 3, and 4. This change does not create any new system
interactions and has no impact on operation or function of any system
or equipment in a way that could cause an accident. The CFCs are not
an initiator of any events, nor do they affect any accident initiators
of any events analyzed in Chapter 15 of the UFSAR. Therefore this
change will not impact the probability of occurrence of an accident.
The results of the reanalysis of the limiting LOCA and MSLB accidents
show that the consequences of an accident previously evaluated are
not increased by the change in the required number of operable CFCs.
This proposed change does not involve a change in plant design,
nor does it involve any potential initiating events that would create
any new or different kind of accident. This proposed change does not
alter the way in which the plant is operated. Therefore, since no
hardware modifications will be made, the proposed change will not
create the possibility of a new or different kind of accident from
any accident previously evaluated.
This proposed change does not adversely impact a margin of safety,
involve a change in plant design, or have any affect on the plant
protective barriers. Therefore, the proposed change will not involve
a significant reduction in the margin of safety.
Based on the above review, it is concluded that: (1) the operation
of the plant with CFC "C" inoperable, does not constitute a significant
hazards consideration as defined by 10 CFR 50.92; (2) there is
a reasonable assurance that the health and safety of the public will
not be endangered by the proposed change; and (3) this action will
not result in a condition which significantly alters the impact of
the station on the environment as described in the NRC Final Environmental
The basis for the licensee's conclusion that the noncompliance will
not involve adverse consequences to the environment.
The requested enforcement discretion does not adversely affect normal
operation of the unit and does not adversely affect any accident analysis
results. Operation within the enforcement discretion will not involve
any change in the types or amounts of effluents that may be released
offsite and no increase in the individual or cumulative occupational
radiation exposure. Therefore, this request for enforcement discretion
does not involve any adverse environmental consequences.
Any proposed compensatory measure(s).
No long term compensatory actions are required. In response to the
unexpected failure of CFC "C," Entergy Operations, Inc. (Entergy)
has determined that the failure is an isolated event. Continued operation
with one fan cooler per train is acceptable from a safety standpoint.
Investigation has determined that CFCs "A," "B," and "D" are currently
operable and capable of fulfilling their intended safety function.
Additionally, TS Surveillance 18.104.22.168 states three temperature inputs
from the four containment fan coolers shall be used to calculate the
arithmetical average of containment temperature. The TS does not require
operation of the associated fan. Procedure OP-903-001 requires that
the inlet temperatures to the three running containment cooling fans
be used to calculate the arithmetical average of containment temperature
for TS Surveillance 22.214.171.124. Therefore, there are no compensatory
actions required due to one fan being inoperable based on the procedural
requirement to use the input from the three running fans.
The justification for the duration of the noncompliance.
The duration for this NOED is until Waterford 3 TS Change Request
NPF-38-224 is approved or an outage of sufficient duration occurs
to accommodate repair of the CFC, which should be RF10 in the fall
of 2000. The justification for the duration is the negligible risk
significance of operating with only one fan cooler operable per CCS
train as compared with the risk associated with potential undesirable
transients as a result of complying with the current TS requirement
to shutdown the plant.
A statement that the request has been approved by the facility organization
that normally reviews safety issues (Plant Onsite Review Committee,
or its equivalent).
This request for enforcement discretion was reviewed by the Plant
Operations Review Committee and approved by the General Manager, Plant
Operations on April 26, 2000.
The request must specifically address how one of the NOED criteria
for appropriate plant conditions specified in Section B is satisfied
This NOED is intended to avoid an undesirable transient as a result
of forcing compliance with the TS as currently written and, thus,
minimize potential safety consequences and operational risks. Without
approval of this enforcement discretion, a plant shutdown will be
required. A plant shutdown is a transient that places thermal stress
on RCS components and increases the potential for plant upset that
challenges safety systems.
If a follow-up license amendment is required, the NOED request must
include marked-up TS pages showing the proposed TS changes. The actual
license amendment request must follow within 48 hours.
Entergy submitted a TS change request on October 18, 1999. This
proposed TS change requested modification of TS 126.96.36.199 LCO to allow
Waterford 3 to operate with two independent trains of containment
cooling consisting of one fan cooler per train, operable during Modes
1, 2, 3, and 4. A copy of the marked-up TS pages was attached to this
request for enforcement discretion.
For NOEDs involving severe weather or other natural events..., acceptability
of any increased radiological risk to the public and the overall public
There are no severe weather or other natural events associated with
this NOED request.
On the basis of the staff's evaluation of your request, we have concluded
that a NOED is warranted because we are clearly satisfied that this action
involves minimal or no safety impact, is consistent with the enforcement
policy and staff guidance, and has no adverse impact on public health
and safety. Therefore, it is our intention to exercise discretion not
to enforce compliance with TS 188.8.131.52 for the period from April 27, 2000,
at 03:45 p.m. hours until issuance of a license amendment pursuant to
your application dated October 18, 1999, or an outage of sufficient duration
occurs to accommodate repair of CFC "C." The staff plans to complete its
review and issue the license amendment within four weeks of the date of
As stated in the Enforcement Policy, action will be taken, to the extent
that violations were involved, for the root cause that led to the noncompliance
for which this NOED was necessary.
Stuart A. Richards, Director
Project Directorate IV and Decommissioning
Division of Licensing Project Management
Office of Nuclear Reactor Regulation
Docket No.: 50-382
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