ML20126E682
| ML20126E682 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 12/16/1992 |
| From: | Brian Holian Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20126E684 | List: |
| References | |
| NUDOCS 9212290268 | |
| Download: ML20126E682 (12) | |
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UNITED STATES-NUCLEAR REGULATORI COMMISSION TU ELECTRIC COMPANY DOCKET NO. 50-445 NOTICE OF CONSIDERATION OF ISSUANCE OF AMENDMENT TO FACILITY OPERATING LICENSE. PROPOSED NO SIGNIFICANT HAZARDS CONSIDERATION DETERMINATION. AND OPPORTUNITY FOR HEARING The U.S. Nuclear Regulatory Commission (the Commission) is considering issuance of an. amendment to facility Operating License No NPF-87.issuedEto-TV Electric ' Company (the licensee) for operation of the Comanche Peak Steam Electric Station, Unit 1 (CPSES) located in Somervell County',-Texas.
'The proposed amendment would revise the Unit 1 Technical Specifications to include revised heatup and cooldown curves.for the reactor coolant system, revised limits for the power-operated relief valve (PORV).setpoints,-and the addition of a specification for feedwater isolation valve pressure / temperature limits. These changes-are required to support:the licensing of Comanche Peak Steam Electric Station Unit 2.
Before issuance of the proposed license amendment, the Commission will have made findings required by the Atomic Energy Act of 1954, asLamended (the Act)!and the Commission's regulations.-
s The Commission has made a proposed' determination that the amendment-request 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; increase in the-probability or? consequences of an accident previously evaluated; or (2) create:the possibility of a new or different kind of 9212290268.921216 1
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e 2-accident from any accident previously evaluated; or (3) involve a-significant--
reduction in a margin of safety. As required by 10 CFR 50.91(a), the licensee has provided.its analysis of the issue of no significant hazards consideration, which is presented below:
(1) The proposed changes do not involve-a significant increase in the probability or consequences of an accident previously' evaluated.
The following changes affect the pressure / temperature limits which define the acceptable regions of operation:
the 50 psi decrease in heatup/cooldown curve; the 39 psi decrease in a portion of the PORV setpoint curve; a
the addition of the 20*F/ hour heatup curve; and the l'F increase in the criticality-limit.
a As such, these changes do not affect the probability.that overpressure events (the events of concern) would occur. These changes only affect the conditions from which events could be initiated.
The consequences.of overpressure events are limited by_ assuring that-the applicable stress limits for the Reactor Coolant System pressure boundary e
(e.g., ASME Boiler and Pressure Vessel Code,Section III, Appendix.G and 10 CFR 50, Appendix G) are not exceeded.
Because the revised acceptable' i
regions of operation still assure that these limits'are not exceeded, these -
changes have no impact on the consequences of an overpressure event.
.The change of terminology to use the adjusted reference temperature (ART) is editorial only.
The changes'in.the ART values-are updates based on the results from the-reactor vessel material irradiation surveillance program. The ART values on
these figures are informational only and do not directly affect plant operation or performance.
The margin for instrumentation error described in the text above the heatup and cooldown curves is changed to reflect the additional 50 psi of measurement' uncertainty which is incorporated into the curves. The margin for instrumentation error as noted on these figures is informational only and does not directly affect plant operation or performance.
In summary, these changes are either editorial or descriptive or only affect the limits which define the acceptable range for operation. As such, these changes do not change the probability or consequences of an accident previously evaluated.
(2) The proposed changes do not create the possibility of a new or different kind of accident from any previously evaluated.
The proposed changes are either editorial or descriptive or only affect the limits which define the acceptable regions for operation. No changes are proposed which could result in a new or different kind of accident from any accident previously evaluated.
(3) The proposed changes do not involve a significant reduction in a margin of safety.
The margin of safety is determined by the failure point for a particular system, structure, or component and the acceptance criteria which are established to ensure that the failure point is not reached during the events of concern.
For these specifications, the failure points of concern are the points at which brittle fracture failures could occur in the Reactor Coolant System (RCS) pressure boundary. The acceptance criteria are, in part, the
pressure / temperature limits provided by Figures 3.4-2 and 3.4-3 and the PORV setpoint limits in Figure 3.4-4.
For the Reactor Coolant System, the severity of the stresses which can exist are determined by the actual temperature, pressure, and heatup/cooldown rates which are allowed. The method of determining the pressure / temperature limit curves for various heatup and cooldown rates is based on approved calculational methodologies which establish an acceptable margin between the actual stresses and the failure point of the materials. An allowance for measurement uncertainties of the instruments is then combined with the actual stresses to produce the heatup/cooldown limit curves.
The different heatup/cooldown rate curves are calculated by the same methodologies and the same instrument uncertainties apply. Therefore, the curve for each heatup/cooldown rate provides essentially the same margin of safety.
For example, for each heatup curve, the maximum stress, and therefore the minimum margin of safety, exists at the heatup rate designated for that curve.
Consequently, the margin of safety for a 60*F/ hour heatup while operating on the 60'F/ hour curve is essentially the same as the margin of safety for a 100'F/ hour heatup while operating on the 100*F/ hour curve.
The new 20*F/ hour heatup curve was determined using the same calculational methodologies as the new 60*F/ hour and 100*F/ hour heatup curves.
The same instrument uncertainties were applied to develop all of these curves and therefore each provides essentially the same margin of safety.
The instrumentation used to assure operation within the allowed range for these curves has not been changed and therefore the uncertainty of the-instrumentation has not changed. However, a previously unrecognized 50 psi-
uncertainty has been incorporated into all of the heatup/cooldown and PORY setpoint curves.
Because the actual instrument uncertainty-is unchanged but the existing curves are being lowered to incorporate an allowance for the additional 50 psi-uncertainty, the maximum stress conditions allowed.o exist have been reduced and the margin of safety has been increased.
As with the heatup and cooldown curves discussed above,-the maximum allowable PORV setpoints specified in Figure 3.4-4 are selected to assure that pressure / temperature limits are not exceeded.
The transients of concern are analyzed including factors such as equipment time delays, instrumentation uncertainties, valve opening times, etc., to ensure that the__ pressure overshoot does not exceed the limits established by Appendix G of Section III of the ASME Boiler and Pressure Vessel code. The PORV setpoint curve is determined by. combining the results of the analysis with the limits determined by the ASME code.
To account for the additional 50 psi uncertainty, the analysis was revised. When the analyses was revised, some overly conservative assumptions were replaced with acceptable but less conservative assumptions.
As a result, the PORV setpoint curve has decreased when below 237'F by 39 psi instead of.50 psi. The other 11 psi was absorbed by._the revised assumptions.
No changes were made to the installed plant hardware or instrumentation.
Thus, an actualcplant transient will progress-in the same manner following thi's change _in PORV setpoint curve except:for the initial conditions, in
..other words, the actual pressure overshoot _for the _ limiting transient is not-expected _to change. The' pressure limits per the ASME code remains essentially unchanged. Therefore, the 39 psi reduction in the setpoint limit (i.e.,
initial: conditions) increases the margin of safety.
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The change in the terminology to use " ART" and the descriptive change in the pressure margin have no direct effect on either plant operations or on the actual margin.
The changes in the ART values are the results of an update of existing calculations and are based on the actual neutron fluence obtained from the reactor vessel material irradiation surveillance ~ program. The revised ART values are used in the calculations of the revised heatup and cooldown curves.
The effects of the changes to the ART values are reflected in the heatup and cooldown curves, but do not directly affect any margins or plant operations.
The fact that the ART values decreased indicates that the reactor vessel is more resistant to brittle fracture; however, the change is so small as to be inconsequential.
The revised criticality limits reflected on Figure 3.4-2 specify pressure / temperature limits for critical core operation in order to provide additional margin during actual power production, in accordance with 10 CFR 50, Appendix G.
The curves are applicable for RCS temperatures-below approximately 350'F.
However, because criticality below an average RCS temperature of 551*F is prohibited by Technical Specification 3.1.1.4, the changes to these limits are descriptive, and have no effect on margin or plant operation.
In summary, the proposed changes are either editorial or descriptive in nature with no effect on margin, or represent an increase in the actual margin of safety.
The NRC staff has reviewed the licensee's analysis and, based on this review, it appears that the three standards of 10 CFR 50.92(c) are satisfied.
1 Therefore, the NRC staff proposes to determine that the amendment request involves no significant hazards consideration.
The Commission is seeking public comments on this proposed determination. Any comments received within thirty (30) days after the date of publication of this notice will be considered in making any final determination. The Comission will not normally make a final determination unless it receives a request for a hearing.
Written comments may be submitted by mail to the Rules and Directives Review Branch, Division of Freedom of Information ana Publications Services, Office of Administration, U.S. Nuclear Regulatory Commission, Washington, DC 20555, and should cite the publication date and page numbcr of this FEDERAL REGISTER notice.
Written 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. Federal workdays. Copies of written comments received may be examined at the NRC Public Document Room, the Gelman Building, 2120 L Street, NW., Washington, DC 20555.
The filing of requests for hearing and petitions for leave to intervene is discussion below.
By January 21, 1993, the license 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 request for a hearing and a petition for leave to intervene. Requests for a hearing and a petition 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 currently copy of 10 CFR 2.714 I
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- which is available at the Commission's Public Document Room, the Gelman Building, 2120 L Street, NW., Washington, DC 20555 and at the local public document room located at the University of Texas at Arlington Library, Government publications / Maps, 701 South Cooper, P. O. Box 19497, Arlington, Texas 76019.
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, 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 CFR 2.714, 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) thc nature of the petitioner's right under the Act to be made party to the 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
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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 factors 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 factors or expert 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 l
to any limitations in the order granting leave to intervene, and have the l
l opportunity to participate fully in the conduct of the hearing, including the opportunity to present evidence and cross-examine witnesses.
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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 i
make it immediately 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 amendme:. 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 in the FEDERAL REGISTER a notice of issuance and provide for opportunity for a hearing after issuance. The Commission expects that the need to take this action will occur very infrequently.
A request for a hearing or a petition for leave to intervene must be filed with the Secretary of the Commission, U.S. Nuclear Regulatory Commission, Washington, DC 20555, Attention: Docketing and Services Branch, or may be delivered to the Commission's Public Document Room, the Gelman
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11 Building 2120 L Street, NW., Washington, DC 20555, 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 Commission 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 N1023 and the following message addressed to Suzanne C. Black:
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, DC 20555, and to George L. Edgar, Esq., Newman and Holtzinger, 1615 L Street, NW., Suite 1000, Washington, D.C.
20336, 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).
For further details with respect to this action, see the application for amendment dated August 31, 1992, as supplemented by letters dated October 29, 1992, and December 14, 1992, which are available for public inspection at the Commission's Public Document Room, the Gelman Building, 2120 L Street, NW.,
Washington, DC 20555 and at the local public document room located at the l
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University of Texas at Arlington Library, Government Publications / Maps, 701 South Cooper, P. O. Box 19497, Arlington, Texas 76019.
Dated at Rockville, Maryland, thi6 16th day of December 1992.
FOR THE NUCLEAR REGULATORY COMMISSION 3%f-Brian E. Holian, Acting Project Manager Project Directorate IV-2 Division of Reactor Projects - !!!/IV/V Office of Nuclear Reactor Regulation i
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