PLA-2006, Interim Part 21 Rept Re Improper Relief Valve Settings & Design Pressures & Temps Found in Hpci,Rcic,Rhr,Core Spray & Essential Svc Water Sys.Initially Reported on 831118. Hydrotests Performed
| ML20086K165 | |
| Person / Time | |
|---|---|
| Site: | Susquehanna  |
| Issue date: | 12/20/1983 |
| From: | Curtis N PENNSYLVANIA POWER & LIGHT CO. |
| To: | Murley T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| REF-PT21-84-149-000 PLA-2006, PT21-84-149, PT21-84-149-000, NUDOCS 8401260323 | |
| Download: ML20086K165 (9) | |
Text
,...
PPal Pennsylvania Power & Light Company.
' Two North Ninth Street
- Allentown, PA 18101
- 2151770LS151 Norman W. Curtis Vice Prosident-Engineering & Construction-Nuclear 215/770-7501 December 20, 1983 Dr.- Thomas E. Murley Regional Administration, Region I U. S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, PA 19406 SUSQUEHANNA STEAM ELECTRIC STATION INTERIM REPORT ON IMPROPER RELIEF VALVE SETTINGS, DESIGN PRESSURES AND DESIGN TEMPERATURES FOR UNIT 2 ER 100508 FILE 821-10 PLA-2006
Reference:
PLA-1972 dated Nov. 30, 1983 PLA-1976 dated Dec. 5, 1983
Dear Dr. Murley:
This letter serves to provide the Commission with an interim report of a deficiency relating to improper relief valve settirgs, design pressures and design temperatures found in the HPCI, RCIC, RHR, Core Spray and ESW Systems in Unit 2.
The deficiency was originally reported as potentially reportable under the previsions of 10CFR50.55(e) in a telephone call between A. R. Sabol and J. Saranga (PP&L) and E. B. McCabe (NRC Region I) on November 18, 1983.
The information contained in this report is submitted pursuant to the provisions of 10CFR50.55(e).
The attachment to this letter contains a description of the problem, its cause, safety implications and the corrective action taken to preclude recurrence.
Since the details of this report provide information relevant to the reporting requirements of 10CFR21 for Unit 2, this correspondence is considered to also discharge any formal responsibility PP&L may have for reporting in compliance thereto.
S 8401260323 831220 h,
PDR ADOCK 05000388 S
2.-
SSES PLA-2006 December 20, 1983 ER 100508 File 821-10 Dr. Thomas E. Murley The Comission was provided with additional information on the cited condition for Unit 1 in the above referenced PLA's.
We trust the Comission will find the information forwarded by this letter to be satisfactory. We expect to furnish a final report on the deficiency in January, 1984.
Very truly yours, D
d
}
/
N N. W. Curtis Vice President-Engineering & Construction-Nuclear bms:sab bms/1t198c Attachment I
I 5
1
_. - +. -,,
-...m,-..,
.- - _.,,.--,...,--,-,.. w
,--,,,...my.,.c-,-,.,-w m_,,-.- -,.
-m-o n.
--_.~r-r-___..
December 20, 1983 3-SSES PLA-2006 ER 100508 File 821-10 Dr. Thomas E. Murley Copy to:
Mr. Richard C. DeYoung (15)
Director-Office of Inspection & Enforcement U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Mr G. Mcdonald, Director Office of Management Information & Program Control U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Mr. Gary Rhoads U.S. Nuclear Regulatory Commission P.O. Box 52 i
Shickshinny, PA 18655 Records Center Institute of Nuclear Power Operations 1100 Circle.75 Parkway, Suite 1500 Atlanta, GA 30339 i
t e
4
+
-rpw.
u-
-r9-g
.y..,,
9 9e-m9.p.r,g--g
,-r..ipp,-p.,,.ce-.7.y 9.,,--y,-3,,7 p,,
qr--7 p
,m,,,,yy.pm-,-*p.,-
.3;4 9._
-.-qy
ER 100508 File 821-10 l
Dr. Thomas E. Murley -
INTERIM REPORT l
Attachment to PLA-2006
SUBJECT:
Improper relief valve settings, design pressures end design temperatures found in the HPCI, RCIC, RHR, Core Spray and ESW systems.
DESCRIPTION:
On October 9,1983, as a result of investigations concerning a routine operational problem concerning a leaking check valve, it was discovered that Bechtel had installed over pressure protection devices in several lines in the HPCI and RCIC Systems, with set points higher than the system design pressures. This condition represented a violation of ASME III Para. NC-7511.
NRC 83-1029 was written to document this deficiency for Unit 1 and Bechtel was contacted and asked to review this problem.
As a result of this review, eleven deficiencies were reported for each Unit 1 and 2, in the HPCI, RCIC, RHR and Core Spray Systems. These deficiencies were noted in NCR 83-1533, and Bechtel was requested to perform stress analysis on all affected lines to determine Unit 1-operability, and any required Unit 2 modifications.
A list of all non-conformances found in Unit 2, as a result of these reviews follows:
Line Number Non-conformance
- 1. 10"HBB-201 Design pressure: 30 psig RCIC turbine exhaust Rupture disk pressure:
150 psig Inadequate overpressure protection exists
- 2. 6" HBB-203 Design pressure:
50 psig RCIC pump suction Relief Valve Setting:
100 psig Inadequate overpressure protection exists
' SSES PLA-2006 ER 100508 File 821-10 Dr. Thomas E. Murley Line Number Non-conformance
- 3. 14" HBB-207 Design pressure: 50 psig HPCI pump suction Relief Valve setpoint:
200 psig Inadequate overpressure protection exists
- 4. 16" HBB-204 Design prassure: 40 psig Core Spray pumps Relief valve setting:
100 psig Suction Inadequate overpressure protection exists i
- 5. 2" 1" & 1/2" HBB-215 Design pressure:
75 psig RCIC discharge to Relief valve setting:
150 psig barometric condenser Inadequate overpressure protection exists
- 6. 2" HBB-239 Design pressure:
100 psig RCIC vacuum pump RCIC suction design press:
150 psig discharge to pump These lines are not isolatable suction therefore the design pressure is inadequate
- 7. 1" and 2" HBB-235 Design pressure:
100 psig HPCI turbine drains Turbine exhaust design press:
175 psig
.to turbine exhaust These lines are not isolatable, therefore, the design pressure is inadequate.
- 8. 4" and 14" EBB-202 Design pressure:
1140 psig HPCI pump discharge Required pressure:
1276 psig Design pressure is inadequate
140 psig suppression pool Design pressure is_ inadequate
- 10. 1-1/2" and 2" HBB-234 Design temp:
140 F HPCI pump discharge Max. operating temp:
170*F to barometric condenser (Post-Loca)
& lube oil cooler Design temperature is inadequate
. SSES PLA-2006 ER 100508 File 821-10 Dr. Thomas E. iiurley Line Number _
Non-conformance
- 11. 12" GBB-218 Design temp (:PostLoca): 340 F 180 F RHR Drywell spray Peak temp.
header Design temperature is inadequate Additionally, Bechtel was requested to review an additional, non G.E.
interface system to determine the scope of these problems. The system chosen by PP&L was emergency service water since it represents one of the most extensive balance of plant systems.
As a result of this review, it has been determined that the design pressure of 136 psig chosen by Bechtel is too low, based on low flow rates and accompanying high system pressures in one of the two loops during normal operations. Also neglected in the Bechtel design was approximately 30 feet of static head between the ESW pump discharges and the lowest system elevations.
The maximum service pressure of 177 psig has been chosen as the proper design pressure for the lowest elevations and the existing piping stress calculations have been reviewed with respect to the effects of this higher pressure on code allowable stress limits.
It has been found that the increased pressure of 177 psig will not cause any of the affected lines to exceed their code allowable stresses.
Therefore, no safety impact for this system exists.
CAUSE:
The problems associated with the report can be categorized as one of three types of deficiencies.
(1) Inadequate over-pressure protection (2) Improper design pressure (failure to consider pump shut-off head, relief valve transients, or connecting line pressures)
(3) Improper design temperature (failure to consider Post-Loca containment atmospheric conditions)
A breakdown of the problems identified into these three problem areas is as follows:
(1) Items 1, 2, 3, 4, 5 and 6
' SSES PLA-2006 ER 100508 File 821-10 Dr. Thomas E. Murley (2) Items 7, 8, 9 and ESW design pressures (3) Items 10 and 11 The apparent causes of these detIciencies are given below:
(1) Inadequate Overpressure Protection.
This deficiency arose from an apparent breakdown in internal communications within Bechtel. Apparently, the relief valves were purchased and installed using the G.E. information found on the process diagrams instead of Spec. M-199 in which the design pressures had been further refined by Bechtel design calculations.
Therefore several relief devices were purchased and installed with design pressure higher than the lines in which they were installed.
(2) Improper Design Pressure. This problem apparently arose from a failure to recognize pressure transients arising from system start-up at pump shut-off head and accompanying relief valve initiation.
Instead, normal operating pressures, which are not sufficiently conservative were used.
In the case of the HPCI pump discharge, it was a failure to recognize that the pump starts before the injection valve opens at which point, the pump shut-off head governs the line pressure rather than the main steam relief valve'setpoints.
In the case of line HBB-220, RHR steam relief to suppression pool, the transient pressure of 140 psig was not considered as the governing design parameter.
For the ESW system, it was a failure to determine that two loop operation would result in one loop operating at low flows and resulting high pressures.
Therefore, in all cases, the wrong system design pressures were specified for the affected lines.
(3) Improper Design Temperature.
The cause of this problem was a failure to consider the combination of Post-LOCA Conditions with system operations.
In the case of line HBB-234, HPCI pump discharge to lube oil cooler, the failure to realize that while the HPCI system is designed to fail if lube oil reaches 170 F for some time and this temperature should then govern the system design.
s
' SSES PLA-2006 ER 100508 File 821-10 Dr. Thomas E. Murley In the design of GBB-218, RHR Drywell Spray Header, the peak temperature was evaluated for this line with water flowing, failing to consider that the'Drywell Spray Header will be empty at the start of the transient and the peak post Loca Drywell temperature is 340 F.
Since this line is open, it can be expected to reach temperatures near this maximum, therefore, this temperature should have been the design value.
SAFETY IMPLICATIONS:
In all cases, with the exception of GBB-218 RHR Drywell Spray Header, a review of the stress calculations and piping has proven that these deficiencies
. represent'no increase in the probability or severity of an accident.
In the case of GBB-218, however, it was found that exposure to peak Post-LOCA Drywell temperatures could cause thermal expansion in excess of its current allowance for growth. This would cause the piping supports to experience additional unanalyzed stresses, rendering their load carrying capability indeterminate. Therefore, additional loading to this line caused by
. initiating Drywell Spray might cause a failure of some of the pipe supports and ultimately a loss of the Drywell Spray System. Therefore, PP&L considered this deficiency as potentially reportable under the provisions of 10CFR50.55(e).
CORRECTIVE ACTION:
Bechtel has performed for PP&L a complete review of all relief valve settings and nodal pressures at piping junctions, in RHR, Core Spray, HPCI and RCIC.
For these lines, existing pipe stress calculations have been or are in the process of being reviewed for all icentified lines with inadequate design pressures. Hydrotests will then be performed to qualify the piping to the new
-design pressures. Specification M-199 will be revised and the N-5 data packages amended to reflect the new design pressures.
In the case of GBB-218, RHR Drywell Spray Header, further analysis is being performed for the affected hangers to determine if safety impact exists.
Hardware modifications will be made if required.
s e
e SSES PLA T,d6 ER 100508 File 821-10 Dr. Thomas E. Murley PP&L has scheduled all analysis and requested retesting to be complete by the end of the current Unit 1 - Unit 2 tie in outage tentatively set to conclude in January, 1984. Additional reviews are ongoing to ensure all similar problems, if any, are surfaced and addressed.
In addition, PP&L has retained an engineering consulting firm to review the corrective actions that have been taken to ensure they are sufficiently comprehensive and technically correct.
The schedule for completion of these activities is under development and we will inform the NRC of its progress and schedule in the January 1984 report.
PP&L anticipates providing the NRC with a final report in addressing the RHR Drywell Spray Header in January,1984.
.