ML20081L175
| ML20081L175 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 06/26/1991 |
| From: | Varga S Office of Nuclear Reactor Regulation |
| To: | DUQUESNE LIGHT CO. |
| Shared Package | |
| ML20081L181 | List: |
| References | |
| NUDOCS 9107020433 | |
| Download: ML20081L175 (9) | |
Text
-
7590-01 i
UtilTED STATES OF At4 ERICA
!;UCLEAP PECUL ATORY COMMISS10!1 In the f>atter of
)
}
DUQUEst:E t IGHT C0tTANY
)
Doctet tio. 50-334
)
(Beaver Valley Power Station,
)
Unit 1)
)
EXE!!PT10ti 1.
Duquesne iight Company (DLC or the liccnsee) is the holder of Pacility Operating License flo. DPR-66 which authorizes operation of the Beaver Valley Power Station, Unit 1 (BVPS-1). This license providos, among other things, that BVPS-1 is subject to all rules, regulations, and Orders of the Comission now or hereafter in effect. BVPS-1 is a pressurized water reactor (PWR) at DLC's site located in Shippingport, Pennsylvania.
General Design Criteria for nuclear power plants are identified in the Gorraission's regulations in Appendix A to 10 CFR Part 50. These criteria establish minimum requireraents for the principal design for water-cooled nuclear power plants. General Design Criterion 57 (CDC 57) states:
Each line that penetrates priraary reactor containment ard is neither part of the reactor coolant pressure boundary nor connected directly to the containment atraosphere shall have at least one containment isolation valve which shall tie either autcratic, or locked closed, or capable of remote manual operation. This valve shall be outside cnntainment and located as close to the containment as practical. I sin-ple check valve may not be used as the automatic isolation valve.
9107020433 910626 PDR ADDCK 05000334 P
The BVPS-1 recirculation-spray heat exchanger (RSHX) river water
- radiation monitor sample lines do not have a containment isolation valve that 1
is automatic, remote-manual, or-locked-closed. Therefore, this configuration does not meet GDC 57, and the updated final Safety Analysis Report (UFSAR) does not describe this deviation from GDC 57.
By letters dated January 11, and March 23, 1990, and April 29, 1991, DLC requested an exemption for BVPS-1 from the requirements of 10 CFR 50, Appendix A, General Design Criterion 57 pertaining to containment isolation l
provisions for a closed system inside containment.-
11.
DLC and the NRC have been aware of this condition for a long time. On 4
March 25, and April 22, 1980, the staff met'with DLC representatives to discuss the consequences of failures and methods to assure integrity of the RSHX. Accordingly, DLC implemented an Inservice Testing (IST) Program j
consisting of a freon test of the RSHXs tube side every 18 months and periodic testing and calibrating of the radiation monitoring system. The staff _ granted permission for continued operation of the plant on the basis that this test program-and the relatively young life of the system provide reasonable assurance of continued integrity of the RSHXs.
The BVPS-1 containment depressurization system has two subsystens, the quench spray and the recirculation spray, which are designed to cool and depressurize the containment within 60 minutes.following a loss-of-coolant accident (LOCA).
Four recirculation spray lines take sater from the containment sump to provide the necessary cooling and depressurization of the P
9 7
9
-e.
.v
--.-,3rn,, -. -
,~u-r e--eme---..., -ce-ww
--, - -..m
=.mu-w-- -. - + -
-.r--.u.
. containment following a LOCA and to maintain subatmospheric pressure in the containment for an extended period following the LOCA.
The four RSHXs are cooled by river water.
Isolation valves at the RSHX river water inlet and return lines are tormally open. During accident conditions, a continuous sample, taken from each heat exchanger river water outlet line upstream of the isolation valve, is monitored for radiation. The sample is returned to the river water discharge line downstream'of the isolation valve. DLC has requested exemption from the requirement of CDC 57 for a containment isolation valve meeting the requirements of GDC 57 for each of the four RSHX river water radiation monitor sample lines.
To support the request for exemption, DLC has asserted that the existing plant configuration presents no adverse effect as a result of postulated I
accidents based on the following considerations:
(1) To release contaminated sump water through the sample line(s) would l
require a RSHX tube leak.
In the event of such a leak, the radiation monitor and the associated high radiation alarm would provide indication r
of the RSHX tube leak and alert the operator to take corrective action.
l l
(2) Existing operating procederes provide for the shutdown of the i
recirculation spray pump in the event of a tube leak thus removing the driving force for the tube leak since the containment is subatmospheric.
This would provide ample time for the operator to then manually isolate l
L
_the sample line.
(3) Periodic examinations and tests-provided in the IST program can detect L
L any RSHX tube degradation and leakage, l
l 1
L....--.---.
DLC's initial submittal was reviewed and the rationale was found to have merit; however, it did not support adequately an exemption from GDC 57. DLC provided additiorial information, via letters dated March 23, 1990, and April 29, 1991. DLC identified trar.ual valves, RW-615, 621, 627, and 033 (one for each sample line), to serve as the containment isolation valves, and committed to include these valves in the Technical Specifications (TS) if the exemption is granted. These valves are located at the radiation n.onitor slid. While there are valves in each sample lint ' hat are closer to containment, the post-accident radiation level in the area of those valves is estir:ated at 3000 R/Hr.
DLC has stated that replacement of these manual valves with automatic or remote-nanual valves is not necessary for the following reasons:
(1) These sample lines are normally open and must be open following an accident to allow rapid detection of any radioactive releases resulting from ; RSHX tube leak.
The radiation monitors, i.e., RM-RW-100A, B, C, and D (one for each sample line), are normally on-line following a LOCA to identify RSHX leakage.
If the radiation n.onitors were isolated automatically or by locked-closed valves, it would take much longer to identify and isolate the leaking RSHX by downstream sampling.
(2) Remote-manual isolation of the sample line has not been provided.
Hcwever, the existing tranual valve can be reached and isolated within 10 rinutes by an cperator dispatched from the control room. Also, the radiation nonitor alarm response procedure will be revised to require closure of thest manual valves in case a RSHX tube leat occurred.
(3) The delay in isolation of the sample line attributable to manual operation would not cause a sigrificant radiation release resulting from the design basis accident because the flow rate (4 ppm) of the 1-inch
i
-5 sample line is approximately one tenth of one percent of the flew rate in the river water line. The flow sampling pumps and the radiation monitors on the sample lines control the flow rate within the 4 gpm limit.
(4) Any leakage from the sarple lines wculd be collected by ficor drains and processed by the licuid waste system.
In a conference call held on August 1, 1990, DLC asserted that the estimated cost to install remote-manual velves in the four sample lines would be about $3EO,000. This estimate includes the costs associated with engineering, materials, and installation of the valves and associated hardware.
In the case of a remote-manual valve, the operators could isolate remotely the appropriate sample line in response to the radiation alarm within a minute of the alarm. Considering that the local manual valve can be reached and closed within 10 minutes of a radiation alarm, the staff concludes that the additional radiation leakage through the 1 inch (4 gpm) sample line would be small. The staff, therefore, has concluded that requiring the installation of remote-manual valves in lieu of the existing manual valves are unwarranted when conpared to the costs for installing the remote-manual valves.
For an automatic valve, DLC addressed only the use of containment isolation signals ior valve closure. Thc staff agrees that the sanple line should function during post-LOCA conditions and standard containment isolation signals are not applicable. Powever, if the isolation signals were associated with the radiation level in the sample line, an automatic valve would be superior to a renote-manual valve in two aspects.
First of all, isolation
I i
r wculd occur f aster and sr.cond there would be no need f or operator action.
However, as discussed for remote-manual valves, the staff concludes that the radiation leakage through a sample line which would occur as a result of the difference in times between the isolation of a local manual and an automatic valve would be small.
Furthermore, automatic isolation of the sanple lines could not be justified without also requiring automatic ola ion of the 14 inch RSHX river water lines for which the staff has previously accepted remote-manual valves.
As in the case of the remote-manual valves, the staff evaluated the costs to install automatic isolation valves in the sample lines. The staff did not ask PLC for Cost data for automatic isolation valves; however, the staff found that the costs would be at least as great as for installing remote-manual valves. Therefore, the steff concludes that the costs for installing automatic isolation valves in lieu of the existing manual valves are not justified considering the safety benefit to be gained.
In evaluating t he acceptability of DLC's position, the staff questioned the accessibility and radiation doses which would be incurred when isolating the local manual valve following an accident.
In the conference call on August 1, 1990, DLC stated that the manual valves would be accessible and the worse case whole body radiation dose which would be received by personnel when isolating the valve would be 5 rems.
The staff considers this to be acceptable since it is below the 10 CFR Part 1C0 linits for emergency conditions.
In addition, the staff considered the fact that the containment is maintained at subatmospheric pressure to minimize radiodctive releases and the plant operating procedures require the shutdown of appropriate recirculation
W 7
spray pumps to stop any leakage. These features would reduce radiation releases while the operators manually isolate the sample lines during either normal or accident conditions.
Based on evaluation of the information provided by DLC as discussed above 4
- and-the fact that DLC performs periodic examinations and tests, through the IST program, to detect any degradation and tube leakage of the RSHX, the staff j
concludes that DLC has provided adequate justification for the integrity of the sample lines with the current isolation configuration. The staff j
concludes that the sample lines should remain o,en to detect any radiation leakage through the RSHX and not be locked-closed.
The existing local manual valves would be accessible for local isolation during accident conditions, and l
the installation of remote-manual or aute. i.ic isolation sample line valves is not warranted based on cost-safety benet considerations. The staff also
- concludes that the subject valves should be included in the Appendix J Type C testing program since they have been designated as containment isolation valves for the_ sample lines.
i 111.
l The Commission has determined, pursuant to 10 CFR 55.11, that this exemption is authorized by law and will not endanger life or property and is otherwise.in the public interest.
Furthermore, the Commission has determined
- that the special circumstances of 10 CFR 50.1?(a)(2)(ii) are applicable in that application of GDC 57 in this instance is not necessary to achieve its
- underlying purpose. The use of locked-closed valves to isolate the sample lines t-c
8 would result in delay in isolating a radiation release due to e leaking RSHX tube, and the use of local manual valves will not result in a significant increase in the total offsite radioactivity release.
further, the Commission has determined that the circumstances of 10 CFR 50.12(a)(2)(iii) are applicable in that the application of the rule would result in undue costs that are significantly in excess of those contemplated when the regulation was adopted. The use of automatic or remote. manual valves would result in undue cost in comparison to the safety benefit to be derived.
The Conriission hereby orants an exemption f rom General Design j
Criterion 57 with respect to the isolation provisions for the RSHX river water radiation monitor sample lines.
Pursuant to 10 CFR 51.32, an environmental assessment and finding of no significant impact has been prepared and published in the Federal Register on June 10, 1991 (56 FR 26699 ).
Accordingly, based upon the environmental assessmant, the Commission has determined that the issuance of this exemption will not have a significant effect on the quality of the human environment.
This exemption is effective upon issuance.
FOR THE NUCLEAR REGULATORY COMMISSION
/s/
Steven A. Varga, Director Division of Peactor Projects - 1/11 Office of Nuclear Reactor Regulation Dated at Rockville, Maryland this 26 day of June 1991.
AD:0RPE fy%
D:DRPE JCalvo SVar a
~~ ~ ~it'DT hibi1 h ~~:f
~3f
~
2 / /91 6/
/91 j
- SEE PREVIOUS CONCURRENCE
" 'Sb iD~$T ' ' "iDGC*
~
WI DFC
- PDT3?I~A
......:..g....
...:........._.J...:
NAME :Sficarris
- ADeAgazio:cn :JFStolz
- CMcCr<
en
- EHoller i
DEiT"!fi[~igi~"'~~!El~$^q lii"""l5i ~~if f'"'\\5}" lbi ~'* ~l5j~ijj9f ~~""
~~
Utt1CIAL RECDRD'CDpi
"~
^"
Document flame: 75772 DEMPTION
Distribution:
9 *"%
Docket file-
=* - /
UNITED STATES PD l-4 File p
NUCLEAR REGL*LATORY COMMISSION g
,y W ASHINGTON, 0.C. 20$$$
4 June 26, 1991
%......o'f DOCm No. 50434 Regulatory Publications Branch MEMORANDUM FOR:
Division of Freedom of information and Publications Services Office of Administration and Resources Management FROM:
Office of Nuclear Reactor Regulaton susJECT: BEAVER VALLEY POWER STATION, UNil 1 One signed original of the Federal Register Notice identified below is enclosed for your transmittal to the Office of the Federal Register for publication. Additional conformed copies (
)of the Notice are enclosed for your use.
Notice of Receipt of Application for Construction Permit (s) and Operating License (s).
Notice of Receipt of Partial Application for Construction Permit (s) and Facility License (s); Time for Submission of Views on Antitrust Matters.
Notice of Consideration oilssuance of Amendment to Facility Operating License.(Catt with __. day insert datel.
Notice of Receipt of Application for Facility License (s); Notice of Availability of Applicant's Environmental Report; and Notice of Consideration of Issuance of Facillty License (s) and Notice of Opportunity for Hearing 1
Notice of Avellability of NRC Draf t/ Final Environmental Statement.
Notice of Umited Work Authorization.
1 Notice of Availability of Safety Evaluation Report.
Notice of issuance of Construction Permit (s).
Notice of lasuance of Facility Operstmg License (s)or Amendment (s)
O Order.
Exemption.
Notice of Granting Exemption.
Environmental Assessment.
Notice of Preparation of Environmental Assessment.
Receipt of Petition for Director's Decision Under 10 CFR 2.206.
Essuance of Final Director's Decision Under 10 CFR 2.206.
Other:
i t
Enclosure:
Project Directorate 1-4 r
As stated
Contact:
$ NorriS
- Phone: X21440 Ome t >
- U A
s s
......7.......,
u-6/ f /91 DATE>,, j,,),,
wac conu sia no,aoi wecu osso OFFICIAL RECORD COPY
-. - - -. - -, -. -. -. - _, - - _. _ -. _. _. _,. ~,.,. -.. -. - -. - - -