ML20058M709
| ML20058M709 | |
| Person / Time | |
|---|---|
| Site: | Waterford  |
| Issue date: | 09/30/1993 |
| From: | Barkhurst R ENTERGY OPERATIONS, INC. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20058M712 | List: |
| References | |
| W3F1-93-0307, W3F1-93-307, NUDOCS 9310060350 | |
| Download: ML20058M709 (14) | |
Text
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, i Ross P. Barkhurst l
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W3F1-93-0307 A4.05 PR September 30, 1993 j Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C. 20555
Subject:
Waterford 3 SES Docket No. 50-382 License No. NPF-38 Emergency Technical Specification Change Request I NPF-38-143 Gentlemen:
1 The attached description and safety analysis support a change to the j Waterford 3 Technical Specifications (TS).
The proposed change would modify TS 3/4.6.3 LCO by incorporating an interim l provision which will allow Containment Spray Valves CS-125(A and/or B) to ;
be maintained in a normally open position.
The proposed change has been evaluated in accordance with 10CFR50.59(a)(1) :
using the criteria in 10CFR50.92(c) and it has been determined that the I change involves no significant hazards considerations. The Waterford 3 !
Plant Operating Review Committee, General Manager Plant Operations, and i Safety Review Committee have reviewed and approved this proposed change based on the forgoing evaluation.
On September 13, 1993, containment spray train A was declared inoperable when it was discovered that the containment spray header isolation valve, CS-125A, would not open with a high differential across the valve. The i differential pressure across the valve developed during the performance of a ESFAS relay surveillance which started and ran the associated containment 060068 931006035o 93o93o r" dv/
yDR ADOCK 05000382 I If PDR L [/
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. i Emergency Technical Specification Change Request NPF-38-143 )
Page 2 Sept aber 30, 1993 i spray pump on its minimum recirculation flow path. A high differential pressure remained across CS-125A after the pump was secured. The header i was subsequently vented, the valve stroked satisfactorily and the Technical Specification action statement was exited.
The valve's failure was documented and entered into the corrective action program by initiation of a condition identification (CI). The CI was assigned to engineering who issued recommendations for interim actions to j be implemented by the operations department. In addition, a condition report (another corrective action document) and NRC notification were initiated on September 17, 1993.
An indeterminate qualification process was initiated when additional information questioned the operability of CS-125A and a special test i procedure was developed for the gathering of system data. Upon the initiation of the special test procedure, containment spray train 'A' was declared inoperable on September 25, 1993, at 1505. Data gathered during l performanc.e of the special test indicated the presence of air in the containment spray piping. The air in the piping created an excessive ,
pressure surge upon pump start that was locked into the piping at valve CS- l 125A by the upstream stop check valves, CS-Illa and CS-117A. j Engineering personnel then revised the special test procedure to accomplish enhanced system venting of air from the system. The 'A' train piping was inspected and a portion of high point piping was discovered that did not have a vent valve. A vent valve was subsequently installed and the piping vented. Other sections of piping were vented through the existing vents by sweeping the system with the containment spray pump. Engineering continued to inspect the 'A' train piping for presence of air by using ultrasonic
, testing methods. Engineering at Waterford 3 consulted hydraulic experts with Ebasco Engineering, in New York, and ccafirmed that the data collected a1pported that the phenomena observed was due to the presence of ain k the rving.
l n b r numerous sweeping and venting efforts, considerable amounts of air l ic n been removed from the systea. As quantities Of air were removed from l the system, the pressure increase observed at have CS-125A was reduced. ]
The systen was then set up to duplicate the <;ituation present during the h
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Emergency Technical Specification Change Request NPF-38-143 -
W3F1-93-0307 _;
Page 3 September 30, 1993 .
t discovery of the initial valve failwe (i.e., post-surveillance). The pressure surge following this testing was less than observed in previous tests indicating that the sweep and vent process was working.
Ultrasonic inspection of the pip'ng revealed a section of piping that had an air pocket remaining. On September 28, 1993, an enforcement discretion ,
was requested to extend the 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> action statement an additional 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> ,
to install another vent valve to remove this air from the system. This !
request was approved. The new vent valve was subsequently installed, and !
the system was filled and vented. In addition, a modification was completed to add an additional vent port on the CS-125A valve actuator to {
decrease valve opening time. Subsequent testing of CS-125A revealed the j valve responded slt.,gishly when operated at pressures where it may be -
required to operate. These actions, as well as other options discussed in several conference calls since Monday September 27, 1993, have failed to .
demonstrate operability of CS-125A.
On September 28, 1993, Waterford 3 requested Enforcement Discretion (W3F1-93-0182) to operate for an additional 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />, to expire -t 1505 hours0.0174 days <br />0.418 hours <br />0.00249 weeks <br />5.726525e-4 months <br /> CST on October 1,1993, with an inoperable A Containment Spray train.
Therefore, pursuant to 10CFR50.91(a)(5) Waterford 3 respectfully requests the Staff review the attached submittal on an emergency basis. As discussed in the attached, the need for an emergency amendment became ;
apparent on September 30, 1993, following the unsuccessful differential ,
oressure tests of CS-125A. Due to these unsuccessful results Waterford 3, ;
absent approval of this emergency request, would be required to begin a !
plant shutdown at 1505 hours0.0174 days <br />0.418 hours <br />0.00249 weeks <br />5.726525e-4 months <br /> on October 1, 1993.
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____________-_O
Emergency Technical Specification Change Request NPF-38-143 i W3F1-93-0307 i Page 4 !
September 30, 1993 .
Should you have any questions concerning the attached information,. please call Paul L. Caropino at (504)739-6692.
Very truly yours, fn y; Y'
({?l\ f)}L/Qf cach{ ;
R.P. Barkhurst Vice President, Operations Waterford 3 RPB/PLC/dc
Attachment:
Affidavit NPF-38-143 :
cc: J.L. Milhoan, NRC Region IV D.L. Wigginton, NRC-NRR R.P. McGehee N.S. Reynolds 1 NRC Resident Inspectors Office i Administrator Radiation Protection Division (State of Louisiana)
American Nuclear Insurers i
r P
UNITED STATES OF AMERICA ,
NUCLEAR REGULATORY COMMISSION.
In the matter of ) '
)
Entergy Operations, Incorporated ) Docket No. 50-382-Waterford 3 Steam Electric Station )
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AFFIDAVIT D.F. Packer, being duly sworn, hereby deposes and says that he is General !
Manager Plant Operations of Entergy Operations, Incorporated; that he is duly ;
authorized to sign and file with the Nuclear Regulatory Commission the '
attached Emergency Technical Specification Change Request NPF-38-143; that he is familiar with the content thereof; and that the matters set forth therein are true and correct to the best of his knowledge, information and belief. .
Vf D.F. Packer General Manager Plant Operations ;
l STATE OF LOUISIANA ) !
) ss PARISH OF ST. CHARLES ) ,
1 Subscribed and sworn to before me, a Notary Public in and for the Parish and l State above named this ~$OTH day of .5EPTEm BER , 1993. j c __,,
._ Dh E . Ic W Notary Public My Commission expires Lv m L F2 . ;
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DESCRIPTION AND SAFETY ANALYSIS OF PROPOSED CHANGE NPF-38-143 The proposed change will modify TS LC0 3.6.3 by incorporating a footnote which states " Containment Spray valves CS-125(A and/or B) may be left in the open position until start-up (prior to entering Mode 4) following Refueling Outage 6".
L Existina Soecification See Attachment A Proposed Snecification See Attachment B ;
i Backaroun,d The Containment Spray (CS) System provides borated water spray for post accident heat removal, pressure reduction and iodine removal from the containment atmosphere. A simplified diagram of the CS system is provided on '
enclosed Figure 1. The system is actuated when the Safety Injection Actuation Signal (SIAS) and the High-High Containment Pressure signal are in coincidence. This generates a Containment Spray Actuation Signal (CSAS) which starts the spray pumps and opens the containment spray header isolation valves CS-125(A and B). The pumps initially draw a suction from the Refueling Water i Storage Pool (RWSP) and deliver borated water to the spray nozzles located at ;
the top of containment. This is called the injection mode. Another mode of I operation called the recirculation mode is automatically initiated by the Recirculation Actuation Signal (RAS) after a low-low level is reached in the RWSP. During this mode of operation, the suction for the spray pumps is taken from the Safety Injection System Sump at the bottom of containment. During normal plant operation, CS system piping is maintained full of water from the RWSP to reduce the CS response time after actuation.
TS LCO 3.6.3 requires that containment isolation valves be operable. The function of the containment isolation system (CIS) is to isolate fluid systems that pass through the primary containment vessel to confine any radioactivity that may be released following a Loss of Coolant Accident (LOCA) or Main Steam Line Break (MSLB) inside containment. !
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Description And Safety Analysis Of Proposed Change NPF-38-143 j Page 2 i Proposed Change !
l The proposed change will allow CS isolation valves CS-125(A and/or B) to be i maintained in the normally open position. As stated earlier these valves are normally maintained in the closed position and open automatically on a CSAS. ,
However, due to problems associated with CS-125A the proposed change will l allow CS-125(A and/or B) to be maintained open until startup (prior to I entering Mode 4) following Refueling Outage 6 (beginning in March 1994). This l action is necessary in order to return CS system train A to operable status. 1 Opening CS-125(A and/or B) is permissible and consistent with the regulations / ;
requirements pertaining to Containment Isolation. .
Justification For Proposed Chanae - Containment Isolation The CS system contains 10 inch check valves CS-128(A & B) located inside ,
containment which perform the system containment isolation function. Outside '
containment the CS system is a water filled closed system. CS-125 A & B are pneumatic operated gate valves which are designed to open upon initiation of a Containment Spray Actuation Signal (CSAS). The valves are also designed to -
fail open and can neither be closed while a CSAS is present nor do they receive an automatic closure signal. Containment spray piping penetrates the .
reactor containment and connects directly to the containment atmosphere. As l such these penetrations (34 A and B) are subject to the General Design '
Criteria of 10CFR50 Appendix A, Criterion 56 (4). Valves CS-129(A & B) are 1/2 inch solenoid oparated globe valves located inside containment in parallel ;
with CS-128(A & B) and are used to detect riser water level indication. !
3 As stated by the staff in their safety evaluation of the Waterford 3 :
Containment Isolation System (NUREG 0787 dated July 1981, Subsection 6.2.4) i
" Automatic isolation valves are provided in those lines which must be isolated l immediately following an accident. Lines which must remain inservice .
following an accident for safety reasons are provided with at least one remote i manual valve." The CS system is an essential ESF system that serves a primary J safety function in mitigating the effects of an accident and CS-125 A & B are :
defined as remote manual valves. )
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4 Description And Safety Analysis 3 Of Proposed Chanty NPF-38-143 Page 3 l
The Standard Review Plan (SRP) section 6.2.4 " Containment Isolation System" subsection II " Acceptance Criteria" provides the acceptable configurations in meeting containment isolation General Design Criteria. Subsection II (item .
paragraph h) states that " Essential systems, such as those described in items '
b and c (i.e., ESF systems), may include remote manual containment isolation valves, but provisions should be made to detect possible leakage from the lines outside containment."
The NRC in its SER (NUREG 0787 Sections 6.2.4 & 22.2.III.D.I.I) has previously reviewed the Waterford 3 classification of the CS system as essential and its inclusion in the leak reduction program in accordance with NUREG 0737 l III.D.I.I requirements. Thus, this SRP criteria is currently being met.
SRP Subsection II (item 6 paragraph j) states that "For engineered safety features system or engineered safety feature-related systems, isolation valves in the lines may remain open or be opened." Thus, maintaining CS-125(A and/or B) open is acceptable per 10CFR50 Appendix A GDC 56 as defined in NUREG 0800 NRC Standard Review Plan.
Justification For Proposed Chance - badvertent Contginment Soray Actuation Section 6.2.1.1 of UFSAR discusses an analysis of an inadvertent containment spray actuation event. The purpose of this analysis was to demonstrate the acceptability of the containment to external pressurization events. The analysis assumes that both CS system pumps are started on an inadvertent CSAS, ;
with a conservative pump flow of 2540 GPM each. The analysis also assumes a conservatively low RWSP temperature (5558F, the Technical Specification minimum). The results of the analysis demonstrate a maximum external pressurization of 0.49 psid with a single failure of one of two vacuum breakers (a 25% margin when compared to the maximum allowed external pressurization of 0.65 psid). Therefore, the consequence of placing CS-125(A and/or B) in the open position is bounded by current accident analysis.
l Placing CS-125(A and/or 8) in the open position does, however, slightly l increase the probability of an inadvertent containment spray event. The l initiators of inadvertent containment spray events fall into 3 categories. l l
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Description And Safety Analysis ,
Of Proposed Change NPF-38-143 Page 4 s
- 1. Spurious CSAS signals (not during maintenance and surveillance).
System design is such that 2 out of 4 channels of CSAS is necessary to initiate Containment Spray. A CSAS signal will then start CS pumps A & ,
B and open CS-125 A & B. Under the proposed change the probability of a ,
spurious CSAS signal will not increase since CS-125 A & B will be in the actuated position.
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- 2. CS pump relay failure.
With CS-125(A and/or B) open, a failure of a CS pump relay would initiate containment spray for the affected train. However,. the consequences of this event, as previously discussed, are bounded by existing accident analysis.
- 3. CSAS signals during maintenance and surveillances.
The probability of inadvertent containment spray for this category of initiators is higher than that of the two previously discussed initiators. However, with strict compensatory measures, as discussed ,
below, the probability of these initiators can be significantly reduced.
The consequences of this event, as previously discussed, are bounded by .
existing accident analysis. !
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Discussion of Proposed Compensatory Measures :
As discussed herein, maintaining CS-125(A and/or B) in the open position results in an additional initiating sequence which can result in an !
inadvertent containment spray. In order to provide compensatory measures to minimize this occurrence, strict administrative control governing operator I actions and preventive measures will be implemented upon approval of this l change. These controls will prescribe additional precautions when the CS I system is subject to increased vulnerability. For example, during periodic ESFAS testing when the chances of an inadvertent pump start is increased, a downstream isolation valve can be closed thus eliminating any increase in probability of a inadvertent containment spray.
1 Description And Safety Analysis Of Proposed Change NPF-38-143 Page 5 Conclusion Waterford 3 has evaluated the aspects associated with maintaining CS-125(A and/or B) in the cpen position. Since CS-125(A and/or B) is in an ESF system,- ,
changing a remote-manual isolation valve from normally closed to normally open is acceptable per the General Design Criteria as defined by the Standard Review Plan.
The slight increase in probability of an inadvertent containment spray has ,
been determined to have no impact on plant safety. Waterford 3 has determined !
that the slight increase in the probability of this event is acceptable when compared to the safety benefit gained by opening CS-125(A and/or B). t Safety Analysis
- 1. Will operation of the facility in accordance with this proposed change involve a significant increase in the probability or consequences of an '
accident previously evaluated? l Response: No Maintaining CS-125(A and/or B) in the open position will have no impact on accidents associated with isolating containment. The Safety i Injection Actuation Signal / Containment Isolation Signal is generated on high containment pressure (17.1 psia) and/or low pressurizer pressure ;
(1684 psia); parameters which indicate a Loss of Coolant Accident (LOCA), Main Steam Line Break (MSLB) or feedwater Line Break (FWLB) in containment. At a containment pressure of 17.7 p;ia the CSAS initiates the containment spray action to mitigate the effects of a LOCA, MSLB or i FWLB. As indicated, those design bases accidents which would initiate .
containment isolation are the accidents that the CS system is designed !
to perform its safety related mitigating function. The Containment Spray System is designed for system pressures and temperatures that l greatly exceed the maximum containment design pressure and temperature.
However, should en event occur requiring containment isolation, but not requiring containment spray, then check valves CS-128(A & B) would provide a containment isolation barrier and the CS system piping water seal would provide a second barrier.
1 Description And Safety Analysis Of Proposed Change NPF-38-143 Page 6 With the establishment of administrative controls the slight increase in the probability of an inadvertent containment spray event is acceptable when compared to the safety benefit gained by opening CS-125(A'and/or I B). The current analysis for containment external pressurization events provides acceptable results with approximately 25% design margin.
This analysis assumes both CS trains inadvertently spraying containment ,
with no operator action. As stated earlier an inadvertent containment ;
spray resulting from this change is bounded by the existing FSAR analysis. !
Therefore, the proposed change will not involve a significant increase in the probability or consequences of any accident previously evaluated.
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- 2. Will operation of the facility in accordance with this proposed change create the possibility of a new or different type of accident from any l accident previously evaluated?
Response: No. .
There are no new or different system interconnections or interactions I associated with maintaining CS-125(A and/or B) open. There is no ,
essential change in how any system is operated.
Therefore, the proposed change will not create the possibility of a new or different kind of accident from any accident previously evaluated.
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- 3. Will operation of the facility in accordance with this proposed change involve a significant reduction in a margin of safety? l i
Response: No The proposed change will allow CS-125(A and/or B) to be maintained j in the normally open position. This change will have no impact on any margin of safety. The inadvertent spray analysis is performed to l demonstrate the acceptability of the containment to external :
pressurization events with a maximum allowed external pressurization of .
0.65 psid. The analysis currently documented in the UFSAR predicts a l maximum external pressurization of 0.49 psid, almost a 25% margin to the limit. As previously stated an inadvertent containment spray due to CS
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Description And Safety Analysis Of Proposed Change NPF-38-143 Page 7 l l
pump relay-failure would initiate containment spray for the effective train. However, the consequences of this event are bounded by the- ;
current analysis. ,
Therefore, the proposed change will not involve a significant reduction in a margin of safety.
Egfety and Sianificant Hazards Determination Based on the above safety analysis, it is concluded that: (1) the proposed change does not constitute a significant hazards consideration as defined by 10 CFR 50.92; and (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 l impact of the station on the environment as described in the NRC final !
environmental statement.
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Figure 1 '
W3F1-93-0307 VENT FIG. 01 CONTAINMENT SPRAY SYSTEM .
STANDBY MODE .
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h VACUUW 6
BREAKERS 600K GAL u CAPAQTY t. ;"
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S S 218 21A HO
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1108 110A 1288 CS u 1298 ~
CS 117B CS 1 58 CS 8A CS 117A 129A -
NCONT. SPRAY l CS 125A PUWP B W 7I s G G h
" SDCHX
? 1 CW CONT. SPRAY i i
RtSER PUMP B
, N 4128 d L g
g 602A
$. PRAY 3 TR B FCYs NC HC g g CS 604A - 6040
'** 106A 107A r
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g SDCHX W gy
RISER PUMP A , TO SDC 101A LPS PUMP A 4 1R A FCVs ^
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ATTACHMENT A NPF-38-143 i
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