ML17305B222
| ML17305B222 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 11/27/1990 |
| From: | Dyer J Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML17305B223 | List: |
| References | |
| NUDOCS 9012060121 | |
| Download: ML17305B222 (24) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION ARIZONA PUBLIC SERVICE COMPANY ET AL.
DOCKET NO. 50-528 PALO VERDE NUCLEAR GENERATING STATION UNIT NO.
1 NOTICE OF CONSIDERATION OF ISSUANCE OF AMENDMENT TO FACILITY OPERATING LICENSE AND PROPOSED NO SIGNIFICANT HAZARDS CONSIDERATION DETERMINATION AND OPPORTUNITY FOR HEARING 7590-01 The U.S. Nuclear Regulatory Commission (the Commission) is considering issuance of an amendment to Facility Operating License No. NPF-41, issued to Arizona Public Service Company, Salt River Project Agricultural Improvement and Power District, El Paso Electric Company, Southern California Edison Company, Public Service Company of New Mexico, Los Angeles Department of Mater and Power and Southern California Public Power Authority (licensees),
for operation of the Palo Verde Nuclear Generating Station, Unit No. 1, located in Maricopa County, Arizona.
The proposed amendment would extend the date for the next regular inspection of steam generator tubes.
This amendment was requested by the licensee's letter of November 14, 1990.
Before issuance of the proposed license amendment, the Commission will have made findings required by the Atomic Energy Act of 1954, as amended (the Act) and the Commission's regulations.
The Commission has made a proposed determination that the request for amendment involves no significant hazards consideration.
Under the Commission's regulations in 10 CFR 50.92, this means that operation of the facility in accordance with the proposed amendment would not (1) involve a significant f%
,qp1.2p c~ pgppp528
~pgpg qp1127 I
i PDR ADO Pvu P
1 II increase in the probability or consequences of an accident previously evaluated; or (2) create the possibility of a new or different kind of accident from any accident previously evaluated; or (3) involve a significant reduction in a margin of safety.
The licensee has provided an analysis that addressed the above three standards in the amendment application.
The NRC staff has reviewed the licensee's analysis as follows:
1.
The proposed Technical Specification amendment will not increase the probability or consequences of an accident previously evaluated because the Unit 1 steam generator tubes have been eddy current examined on four previous occasions since 1981.
The most recent examination was July 1989, with 100 percent of the tubes being examined.
The results of the examination determined that the indications identified are primarily associated with mechanical wear as opposed to chemistry or corrosion problems.
The mechanical wear is due to vibration associated with normal plant operation.
The overall results of the examination are very good, in that after completion of the second fuel cycle, the total number of degraded and!'or defective tubes was minimal (19 tubes being plugged) and no significant wear patterns were observed.
Since the July 1989 eddy current examination, Unit 1 was shutdown until June 1990.
During this time there was no mechanical wear that could contribute to tube degradation.
Also during this shutdown period, chemistry control was maintained in accordance with plant procedures which dictates strict adherence to prescribed lay-up practices and specifications.
T I
t 1
ll
The Unit 1 steam generators entered wet-layup conditions on April 15, 1989.
Other than the nitrogen overpressure not being maintained within specifications because of the main steam isolation valve (MSIV) work undertaken and the wet-layup recirculation line out of service for rework, the remaining chemistry control was well maintained with only a few instances when chemistry analyses indicated out of specification conditions.
The pH was slightly low (SG fl) at 9.7 (specification is 9.8 to 10.5) on May 5, 1989.
- Chloride, sulfate, and sodium were well below the 1.0 ppm specification limit during the entire period.
Hydrazine ranged from 81 to 176 ppm with an average of 123 ppm (75-200 ppm is the range).
The two occurrences of possible concern were the lack of a nitrogen overpressure while the MSIV work was undertaken and the lack of sampling between September 25, 1989 and November 16, 1989.
During wet-layup, steam generator sampling is accomplished via the wet-layup recirculation line.
This line was out of service due to repair of a valve in the recirculation system.
The first hydrazine analysis after this period showed no appreciable depletion in hydrazine concentration.
Subsequent samples taken after restoration of the recirculation system showed a slight change from 155 to 123 ppm.
Similar conditions existed for SG82 during this time period with hydrazine still well within the band of 75 to 200 ppm as prescribed in procedure 74AC-9CY04.
And again the sodium, chloride, and sulfate were well within the wet-layup specification.
Both steam generators had hydrazine contents of at least 80 ppm, with chloride, sulfate, and sodium below the I ppm limit.
Both steam generators had one day where the pH dropped below the specified 9.8.
- 4 The concern with the lack of nitrogen overpressure and wet-layup chemistry would be the potential impact of corrosion on the steam generator.
In order to evaluate this possibility, an evaluation was undertaken by the steam generator manu facturer.
The materials of construction for the steam generators are grouped in the following categories:
Alloy 600 is used for the heat transfer steam generator tubes.
Ferritic stainless steel (type 405 or 409) used for eggcrates, batwings and flow distribution plate.
Low alloy steels or carbon steel is used for tubesheet stay, shells, baffles, dryers arid separators.
In su+vary, the lack of nitrogen overpressure surveillance when considered in conjunction with the remaining wet-layup chemistry is not expected to have any adverse corrosion effects.
Specifically, pitting should not occur in the Alloy 600 tubing.
Although the water was exposed to oxygen, the pH was maintained between 9.8 and 10.5, (except for one day where the pH dropped to 9.7) above which should prevent copper chloride (CuC12) induced pitting of Alloy 600 tubing.
Therefore, general corrosion is not a problem with Alloy 600 at these shutdown conditions.
General corrosion is also not a problem with ferritic stainless steels containing at least 11 percent chromium (Cr) at these shutdown conditions.
General corrosion is a concern with low alloy and carbon steel surfaces exposed to the vapor phase during wet-layup if sufficient nitrogen overpressure
is not maintained.
It is assumed that atmospheric air would eventually replace the nitrogen originally present.
As such, the presence of oxygen in the vapor space permits the oxidation of the protective magnetite (Fe304) to the less protective h~matite (Fe203 - rust).
At startup, this will add to the amount of material that must be processed and removed.
In the immersed section, general corrosion of the carbon and low ally steels will not occur due to the high pH and the presence of hydrazine.
The presence of oxygen in the vapor space of the steam generators during shutdown shou1d not affect the integrity of the system.
Its presence
- however, is expected to increase the general corrosion to the exposed carbon steel and low alloy steel surfaces and create more sludge.
The accident or event of conern regarding the steam generators would be a steam generator tube rupture (SGTR).
The radiological releases calculated for a SGTR event with a loss of offsite power and a fully stuck open atmospheric dump valve (ADY) are well within the guidelines of 10 CFR Part 100.
The RCS and secondary system pressures are we11 below 110 percent of the design pressure limits, thus assuring the integrity of these systems.
Additionally, no violation of the fuel thermal limits occurs, since the minimum DNBR remains above the 1.24 value throughout the duration of the event.
Based on the July l989 100 percent eddy current examination, where no significant wear patterns or corrosion buildup was observed and the fact that chemistry was maintained during wet-layup, the proposed change will not increase the probability of an accident previously evaluated.
The proposed change will
'l 1
not increase the consequences of an accident previously evaluated due to the fact that in the event of a steam generator tube rupture the caluclated radiological releases are well within the guidelines of Part 100.
2.
The proposed Technical Specification amendment will not create the possibility of a new or different kind of accident from any accident previously evaluated because the Chapter 15 analysis assumes that the plant is challenged by a SGTR that includes additional events and failures beyond those postulated by the NRC Standard Review Plan (SRP) 15.6.3.
In addition to the conservative assumptions of the SRP (loss of offsite power, iodine spiking, etc.), this analysis postulates that the operators open an ADV on the affected steam generator and that it both runs to the full open position and sticks full open for the duration of the transient.
The results of which are well within the guidelines of 10 CFR Part 100 for any radiological releases and the RCS and secondary system pressures are well below the design pressure limits.
Therefore the proposed Technical Specification amendment will not create the possibility of a new or different kind of accident from any accident previously evaluated.
3.
The proposed Technical Specification amendment does not involve a significant reduction in a margin of safety because no changes are being made to the way the facility is being operated.
- Thus, no new failure modes are being introduced.
If a SGTR were to occur, diagnosis of the event is facilitated by radiation monitors, which initiate alarms and inform the operator of abnormal levels and that corrective operator action is required.
Additional diagnostic information is provided by RCS pressure and pressurizer level response indicating a leak, and by level response in the affected steam generator.
The most limiting SGTR event is for a leak flow equivalent to a double-ended rupture of a U-tube at full power conditions. This event has been analyzed for Palo Verde (UFSAR Section 15.6.3) and concludes that the resultant radiological releases are well within 10 CFR 100 guidelines and the RCS and secondary system pressures are well below 110 percent of the design pressure limits and no violation of the fuel thermal limits occurs.
Therefore, the proposed Technical Specificationamendment will not involve a significant reduction in a margin of safety.
Therefore, based on the above considerations, the Commission has made a
proposed determination that the request for amendment involves no significant hazards consideration.
The Commission is seeking public comments on this proposed determination.
Any comments received within 30 days after the date of publication of this notice will be considered in making any final determination.
The Commission will not normally make a final determination unless it receives a request for a hearing.
Mritten comments may be submitted by mail to the Regulatory Publications Branch, Division of Freedom of Information and Publications Services, Office of Administration, U.S. Nuclear Regulatory Commission, Mashington, D.C.
- 20555, and should cite the publication date and page number of this FEDERAL REGISTER notice.
Mritten comments may also be delivered to Room P-223, Phillips Building, 7920 Norfolk Avenue, Bethesda, Maryland, from 7:30 a.m. to 4:15 p.m.
Copies of written comments received may be examined at the NRC Public Document Room, the Gelman Building, 2120 L Street N.M., Mashington, D.C.
The filing of requests for hearing and petitions for leave to intervene is discussed below.
I II II h
By January 3 199), the licensees may file a request for a hearing with respect to issuance of the amendment to the subject facility operating license and any person whose interest may be affected by.this proceeding and who wishes to participate as a party in the proceeding must file a written petition for leave to intervene.
Requests for a hearing and petitions for leave to intervene shall be filed in accordance with the Commission's "Rules of Practice for Domestic Licensing Proceedings" in 10 CFR Part 2.
Interested persons should consult a current copy of 10 CFR 2.714 which is available at the Commission's Public Document Room, the Gelman Building, 2120 L Street, N.M., Mashington, D.C.
20555 and at the local public document room located at the Phoenix Public Library, 12 East McDowell Road, Phoenix, Arizona 85004.
If a request for a hearing or petition for leave to intervene is filed by the above date, the Commission or an Atomic Safety and Licensing Board, designated by the Commission or by the Chairman of the Atomic Safety and Licensing Board Panel, will rule on the request and/or petition and the Secretary or the designated Atomic Safety and Licensing Board will issue a
notice of hearing or an appropriate order.
As required by 10 CFR52.714, a petition for leave to intervene shall set forth with particularity the interest of the petitioner in the proceeding, and how that interest may be affected by the results of the proceeding.
The petition should specifically explain the reasons why intervention should be permitted with particular reference to the following factors:
(1) the nature of the petitioner's right under the Act to be made a party to th'e proceeding; (2) the nature and extent of the petitioner's property, financial, or other interest in the proceeding; and (3) the possible effect of any order which may
be entered in the proceeding on the petitioner's interest.
The petition should also identify the specific aspect(s) of the subject matter of the proceeding as to which petitioner wishes to intervene.
Any person who has filed a petition for leave to intervene or who has been admitted as a party may amend the petition without requesting leave of the Board up to fifteen (15) days prior to the first prehearing conference scheduled in the proceeding, but such an amended petition must satisfy the specificity requirements described above.
Not later than fifteen (15) days prior to the first prehearing conference scheduled in the proceeding, a petitioner shall file a supplement to the petition to intervene which must include a list of the contentions which are sought to be litigated in the matter.
Each contention must consist of a specific statement of the issue of law or fact to be raised or controverted.
In addition, the petitioner shall provide a brief explanation of the bases of the contention and a concise statement of the alleged facts or expert opinion which support the contention and on which the petitioner intends to rely in proving the contention at the hearing.
The petitioner must also provide references to those specific sources and documents of which the petitioner is aware and on which the petitioner intends to rely to establish those facts or exper t opinion.
Petitioner must provide sufficient information to show that a genuine dispute exists with the applicant on a material issue of law or fact.
Contentions shall be limited to matters within the scope of the amendment under consideration.
The contention must be one which, if proven, would entitle the petitioner to relief.
A petitioner who fails to file such a supplement which satisfies these requirements with respect to at least one contention will not be permitted to participate as a party.
Those permitted to intervene become parties to the proceeding, subject to any limitations in the order granting leave to intervene, and have the opportunity to participate fully in the conduct of the hearing, including the opportunity to present evidence and cross-examine witnesses.
If a hearing is requested, the Commission will make a final determination on the issue of no significant hazards consideration.
The final determination will serve to decide when the hearing is held.
If the final determination is that the amendment request involves no significant hazards consideration, the Commission may issue the amendment and make it effective, notwithstanding the request for a hearing.
Any hearing held would take place after issuance of the amendment.
If the final determination is that the amendment request involves a
significant hazards consideration, any hearing held would take place before the issuance of any amendment.
Normally, the Commission will not issue the amendment until the expiration of the 30-day notice period.
However, should circumstances change during the notice period such that failure to act in a timely way would result, for example, in derating or shutdown of the facility, the Commission may issue the license amendment before the expiration of the 30-day notice period, provided that its final determination is that the amendment involves no significant hazards consideration.
The final determination will consider all public and State comments received.
Should the Commission take this action, it will publish a notice of issuance and provide the opportunity for a hearing after issuance.
The Commission expects that the need to take this action will occur very infrequently.
J A request for a hearing or a petition for leave to intervene shall be filed with the Secretary of the Commission, U.S. Nuclear Regulatory Commission, Washington, D.C.
20555, Attention:
'Docketing and Service Branch, or may be delivered to the Commission's Public Document Room, the Gelman Building, 2120 L
Street N.W., Washington, D.C., by the above date.
Where petitions are filed during the last ten (10) days of the notice period, it is requested that the petitioner promptly so inform the Comoission by a toll-free telephone call to Western Union at 1-800-325-6000
( in Missouri 1-800-342-6700).
The Western Union operator should be given Datagram Identification Number 3737 and the following message addressed to James E. Dyer:
petitioner's name and telephone number; date petition was mailed; plant name; and publication date and page number of this FEDERAL REGISTER notice.
A copy of the petition should also be sent to the Office of the General
- Counsel, U.S. Nuclear Regulatory Commission, Washington, D.C.
- 20555, and to Arthur C. Gehr, Esq., Snell and Wilmer, 3100 Valley Center, Phoenix, Arizona 85073, attorney for the licensee.
Nontimely filings of petitions for leave to intervene, amended petitions, supplemental petitions and/or requests for hearing will not be entertained absent a determination by the Commission, the presiding officer or the presiding Atomic Safety and Licensing Board, that the petition and(or request should be granted based upon a balancing of the factors specified in 10 CFR 2.714(a)(1)(i)-(v) and 2.714(d).
I(
I t
I t
hl I
t For further details with respect to this action, see the application for amendment dated November 14, 1990, which is available for public inspection at the Coamission's Public Document Room; the Gelman Building, 2120 L Street N.W.,
Washington, D.C.
- 20555, and at the Local Public Document Room, Phoenix Public Library, 12 East McDowell Road, Phoenix, Arizona 85004.
Dated at Rockvil le, Maryland this 27thday of November 1990.
FOR THE NUCLEAR REGULATORY COMMISSION James E. Dyer, Acting Director Project Directorate V
Division of Reactor Projects III/IV/V Office of Nuclear Reactor Regulation
'4