ML20235W677
| ML20235W677 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 10/08/1987 |
| From: | Gallagher J PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | NRC, NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| RTR-NUREG-0737, TASK-2.B.2, TASK-TM NUDOCS 8710160354 | |
| Download: ML20235W677 (7) | |
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PHILADELPHIA ELECTRIC COMPANY 2301 MARKET STREET P.O. BOX 8699 PHILADELPHIA. PA.191o1 (215) 841 5001 JOSEPH W. G A LLAGHE R
....T.'d".".'.*I,"[... -
October 8, 1987 Docket Nos. 50-277 50-278 8- $ '
- c Director
~3 ES Office of Inspection & Enforcement U.S. Nuclear Regulatory Commission 3> E$
ATTN:
Document Control Desk C$
Washington, D.C.
20555' c2
SUBJECT:
Response to Notice of Violation and Enforcement Conference (NRC Inspection Nos. 50-277/87-17 and 50-278/87-17)
Dear Director:
Attachment A is our response to the Notice of Violation identified in a Nuclear Regulatory Commission letter dated September 8, 1987 concerning a " Notice of Violation and Enforcement Conference Report (NRC Inspection Nos. 50-277/87-17; 50-278/87-17)".
In the September 8, 1987 letter, a violation was l
identified with regards to incorrect piping configurations in the Control Room Ventilation Radiation Monitoring System.
This deficiency was previously identified to the Nuclear Regulatory Commission by Philadelphia Electric Company in a Licensee Event Report dated July 1, 1987 and was the subject of an Inspection Report (50-277/87-17;50-278/87-17) previously sent to Philadelphia Electric Company on July 31, 1987.
On August 13, 1987, an enforcement conference was conducted with Philadelphia Electric Company regarding this event.
If you have any questions or require additional information, please do not hesitate to contact us.
i Very truly yours, TRL:mlh 8710160354 871000 ADOCK 05000g 7 Attachments DR cc: Addressee W. T. Russell, Administrator, Region I, USNRC T.
P. Johnson, Resident Site Inspector g,C[
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t Attcchment P gn 1 of 4
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Docket Nos. 50-277 50-278 Violation:
Technical Specification Limiting Condition for Operation (LCO) 3.ll.A.5 requires that whenever the control room emergency ventilation system is required to be operable in accordance with Technical Specification LCO 3.11.A.1, at least one of two control room intake air radiation monitors shall be. operable with the inoperable channel failed safe, or emergency filtration of the control room ventilation intake air must be initiated.
Technical Specification LCO 3.11.A.1 requires that the control room emergency ventilation system be operable whenever secondary I
containment' integrity is required.
l t
Contrary to the above, prior to May 29, 1987, during l
periods when secondary containment integrity was required, both control room intake air radiation monitors were inoperable and emergency filtration of the control room air was not initiated.
The radiation monitors were inoperable in that the monitors were receiving a sample of emergency ventilation suction rather than
'i normal ventilation suction because the sensing lines to the sample valve had been reversed.
i Admission or Denial of the Violation:
Philadelphia Electric Company acknowledges the violation as stated.
Reason for the Violation:
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On May 29, 1987, it was discovered that an incorrect piping configuration existed in the Control Room Ventilation Radiation Monitoring System.
As a result of the piping configuration errors, the Control Room Ventilation Radiation 7
Monitoring System would not have been able to detect rapidly abnormal radiation conditions.
This would have delayed the actuation of the emergency ventilation system as described in the Final Safety Analysis Report.
Specifically, the sample lines from the normal ventilation duct and the emergency ventilation duct to three of four solenoid valves (SV-0760A, SV-0760B, SV-0760D) were reversed.
The sample lines to SV-0760C were piped correctly.
This discovery occurred during an investigation of suspected low l
flow through the
'B' channel of the Control Room Ventilation l
Radiation Monitoring System.
l
Attachmont
'Page 2'of 4 Docket Nos. 50-277 50-278 1
I Il L
Figure'l (attached) shows the sample lines.in the as
.found -(incorrect) piping. configuration discovered on May 29, i
1987.
Figure 2 (attached) shows the as left (corrected) sample lines.
l
, ;The cause ofuthe; incorrect. piping configurations has been determined to be the result of inadequate installation I
during construction, and the. failure to perform an adequate preoperational test verification of.the sample line routing.
The l
periodic-surveillance tests performed on the system were developed" based'on the assumption:that the lines were correctly connected.
Extent or Significance of The Violation:
d In'an effort to determine if conditions similar to the deficiency described in the Inspection Report exist in other j
systems at-the Peach Bottom Atomic Power Station, a program has been initiated by Philadelphia Electric Company to assure that parameters which cause the actuation of a safety system.are
-properly " sensed".
This program consisted of a review of 32 systems.
Of the'32 systems, 23 have been completely reviewed to 1
date.
Therefore, a supplemental response to this Inspection 1
Report'willnbe submitted that describes the results of this l
review'and evaluates the extent and significance of any possible o
nonconformances similar to the deficiency' described in this f
Inspection Report.
Further information concerning this review is l
discussed below.
]
Additionally, dose calculations were performed to 1
determine the significance of the increase in the operator's l
potential post-accident exposure due to the incorrect piping j
configuration.
The results of these calculations show that the increase in-the operators post-accident exposure would be minimal and the total post-accident exposure would remain well within the 1
regulatory limits of General Design Criteria-19.
l d
q The preliminary analysis was discussed in Licensee Event Report No. 2-87-08, dated July 1, 1987.
Subsequent to this
(
preliminary analysis, a more refined calculation has been performed.to quantify.the potential operator exposure consequences of the' misaligned radiation monitoring system.
Tnis
- I calculation was performed using an analytical model and assumptions consistent with the " Design Review of Plant Shielding" submitted in response to NUREG 0737.
In the NUREG-0737 submittal, the airborne activity in the control room may be the result of either bypass leakage (leakage past the Main Steam Isolation' Valves (MSIVs) which exfiltrates from the condenser) or Standby nas Treatment System (SGTS) exhaust flow.
Due to the 1
2 _____ _ _____________
o o,
c.-
a Attachment
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Page 3 of 4 Docket Nos. 50-277 50-278-e' 1
1 location of these.two-sources with respect to the contro1~ room l
o ventilation intake,.it is not credible'for the intake.to.be i
exposed to activity._from both sources at the same~ time.
LThe specific difference between the refined calculation-l and'tbo preliminary-analysis.is.that the. refined calculation analyzed the effect of bypass leakage on control room operator
- exposure while the preliminary = analysis assumed that'the-SCOS exhaust flow would result.in the higher and more conservative operator exposure.
However, the results ofLthe refined calculation demonstrates that'the. contribution from bypass
. leakage would have resulted in a longer delay time in. emergency
- filtration; system actuation and increased operator-exponure.
The results of the refined calculation show'that operator post accident exposures with the' sample lines misaligned'would have remained at :less than:lt of the General Design Criteria-19
. thyroid. dose limit of 30 rem.- These results are summarized in the~ table below l
Delay in Emer.
% of GDC 19 i
Vent. System Thyroid Dose Criteria
~ Actuation (MREM)
(30 REM) 1 As designed radiation 270 0.90%
monitoring' system (A) bypass contribution
' Misaligned radiation 23 hr.
290 0.97%
1 monitoring system l
bypass contribution
)
Notes (A) Ref. NUREG-0737 submittal item II.B.2.2 - Case A l
l 1
Corrective Actions:
)
Upon discovery of the incorrect piping configurations, the sample lines to solenoid valves SV-0760B and D were realigned o
in'the correct configuration.
Approximately two hours elapsed I
L between discovery of the misalignment and return to the correct configuration of SV-0760B and D.
The sample lines to SV-0760A were realigned correctly'on June 1,
- 1987, l
i Additionally, all other ventilation radiation monitoring 1
systems at Peach Bottom Atomic Power Station were checked for proper piping configurations.
No discrepancies were found.
j I
I l
l l
a=_-___-____-__
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1/3 Attachment-Page 4 of 4 Docket Nos. 50-277 50-278
_ Corrective Actions Taken To Prevent Recurrence and Results Achieved:
As an action to assure that a condition similar to the
-deficiency described in the Inspection Report does not exist in other safety systems at the Peach Bottom Atomic Power Station, a program has been-initiated to determine that safety parameters whichicause the actuation of a safety system are properly "senerc.
This program consisted of a review of 32 systems.
Of the 32 systems, 23 systems have been completely reviewed to date.
.As a first step of the review, all safety systems at the Peach Bottom Atomic Power Station which depend on sensing process parameters were identified.
This initial step identified 32 systems.
OfLthese 32 systems, 15 systems do not depend on
. sensing parameters'for-the automatic initiation of the system, i.e., the systems are manually initiated and are not subject to faulty process parameter input for initiation.
These 15 systems were eliminated from further review.
Of the. remaining 17 systems, functional control drawings, electrical cchematics and piping and instrumentation diagrams were reviewed to identify every instrument that senses a process parameter and causes the' automatic initiation of a safety system.
From the identification of each instrument, a review of plant operating reports was conducted to determine if the instrumentation has previously initiated a safety system action by. properly sensing a process parameter.
Additionally, a review i
of surveillance tests was conducted.to determine if the test i
verifies that the instrumentation properly senses the process l
parameter.
As a result of this review, eight of th.= remaining 17 systems have had correct sensing of their process parameters demonstrated by surveillance tests or by actual actuation during an event, these systems include the RCIC, HPCI, Core Spray, LPCI,
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Main Steam Line Radiation Monitors, Standby Gas Treatment Systems, Standby AC Power System (Diesels) and the DC Power System.
Therefore, these systems were also eliminated from i
further review.
'For these remaining nine systems, action plans will be developed to perform this verification.
These action plans will include such verification methods as plant walkdowns, performance of special tests, or observations of certain process parameters that have indication in the Main Control Room.
These actions will be completed prior to plant startup, except for those i
instruments for which actual process conditions are needed to l
perform the verification, in which case, the actions will be i
i completed during the upcoming plant startup.
As discussed above, I
a supplemental Inspection Report will be submitted which describes the results of this review.
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