ML20236L282
| ML20236L282 | |
| Person / Time | |
|---|---|
| Site: | Wolf Creek  |
| Issue date: | 07/07/1998 |
| From: | Thomas K NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20236L284 | List: |
| References | |
| NUDOCS 9807100297 | |
| Download: ML20236L282 (13) | |
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7590-01-P UNITED STATES NUCLEAR REGULATORY COMMISSION WOLF CREEK NUCLEAR OPERATING CORPORATION DOCKET NO. 50-482 NOTICE OF CONSIDERATION OF ISSUANCE OF AMENDMENT TO FACILITY OPERATING LICENSE. PROPOSED NO SIGNIFICANT HAZARDS l
CONSIDERATION DETERMINATION. AND OPPORTUNITY FOR A HEARING The U.S. Nuclear Regulatory Commission (the Commission) is considering issuance of an amendment to Facility Operating License No. NPF-42 issued to Wolf Creek Nuclear l
Operating Corporation (the licensee) for operation of the Wolf Creek Nuclear Generating Station, Unit No.1 located in Coffey County, Kansas, j
The proposed amendment would support a modification to the plant to increase the storage capacity of the spent fuel pool and increase the maximum nominal fuel enrichment to j
5.0 nominal weight percent U-235.
I 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 amendment request j
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 accident from l
9007100297 900707 PDR ADOCK 05000482 l
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2 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 change does not involve a significant increase in the probability or consequences of an accident previously evaluated.
in the analysis of the safety issues concoming the expanded Spent Fuel Pool storage capacity, the following previously postulated accident scenarios have been considered:
a.
A spent fuel assembly drop in the Spent Fuel Pool b.
Loss of Spent Fuel Pool cooling flow c.
A seismic event d.
Misloaded fuel assembly The probability that any of the accidents in the above list can occur is not significantly increased by the modification itself. The probabilities of a seismic event or loss of Spent Fuel Pool cooling flow are not influenced by the proposed changes. The probabilities of accidental fuel assembly drops or misloadings are primarily influenced by the methods used to lift and move these loads. The method of handling loads during normal plant operations is not significantly changed, since the same equipment (i.e., Spent Fuel Pool Bridge Crane) and procedures will be used. A new offset handling tool will be required to assess some storage rack cells located adjacent to the pool walls. The grapple mechanism, procedures, and fuel manipulation methods will be very similar to those used by the spent fuel handling tool. Therefore, this tool does not represent a significant change in the methods used to lift or move fuel. Since the methods used to move loads during normal operations remain nearly the same as those used previously, there is no significant increase in the probability of an accident.
During rack removal and installation, all work in the pool area will be controlled and performed in strict accordance with specific written procedures. Any movement of fuel assemblies required to be performed to support the modification (e.g., removal and installation of racks) will be performed in the same manner as during normal refueling operations. Shipping cask movements will not be performed during the modification period.
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3-Accordingly, the proposed modification does not involve a significant increase in the probability of an accident previously evaluated.
The consequences of the previously postulated scenarios for an accidental drop of a fuel assembly in the Spent Fuel Pool have been re-evaluated for the j
proposed change. The results show that the postulated accident of a fuel assembly striking the top of the storage racks will not distort the racks sufficiently to impair their functionality. The minimum subcriticality margin, K.,less than or equal to 0.95, will be maintained. The structural damage to the Fuel Building, pool liner, and fuel assembly resulting from a fuel assembly drop striking the pool floor or another assembly located within the racks is primarily dependent on the mass of the fa!!ing object and the drop height. Since these two parameters are not changed by the proposed modification, the structural damage to these items remains unchanged. Cycle specific calculations, using core specific parameters continue to ensure that the radiological dose at the exclusion area boundary remain within the limits documented in the WCGS (Wolf Creek Generating Station] Updated Safety Analysis Report. Dose levels remain well within the levels required by 10 CFR 100, paragraph 11, as defined in Section 15.7.4.ll.1 of the Standard Review Plan. Thus, the results of the postulated fuel drop accidents remain acceptable and do not represent a significant increase in consequences from any of the same previously evaluated accidents that have been reviewed and found acceptable by the NRC.
The consequences of a loss of Spent Fuel Pool cooling have been evaluated and found to have no increase. The concem with this accident is a reduction of Spent Fuel Pool water inventory from bulk pool boiling resulting in uncovering fuel assemblies. This situation would lead to fuel failure and subsequent significant increase in offsite dose. Loss of Spent Fuel Pool cooling at WCGS is mitigated in the usual manner by ensuring that a sufficient time lapse exists between the loss of forced cooling and uncovering fuel. This period of time is compared against a reasonable period to re-establish cooling or supply an altemative water source. Evaluation of this accident usually includes determination of the time to boil. The time allowed for operator action is much less than the onset of any significant increase in offsite dose, since once boiling begins it would have to continue unchecked until the Spent Fuel Pool surface was lowered to the point of exposing active fuel. The time to boil represents the onset of loss of Spent Fuel Pool water inventory and is commonly used as a gage for establishing the comparison of consequences before and after a refueling project. The heat up rate in the Spent Fuel Poolis a nearly linear function of the fuel decay heat load. The fuel decay heat load will increase subsequent to the proposed changes because of the increase in the number [of]
assemblies and higher fuel bumups. The methodology used in the thermal-hydraulic analysis determined the maximum fuel decay heat loads which are allowed by maintaining the current time allowed for operator action (i.e., more than two hours to boli during complete loss of forced cooling). Therefore, the
(,n;,
p allowed operator action time remains unchanged from the previous design basis.
In the unlikely event that all Spent Fuel Poot cooling is lost, sufficient time will still l
l be available subsequent to the proposed changes for the oparators to provide p
' altamate means of cooling before the onset of pool bol!ing. Therefore, the j'
proposed change represents no increase in the consequences of loss of Spent L.
Fuel Poc! cochng.
I The consequences of a design basis seistnic event are notincreased. The consequences of this accident are evaluated on the basis of subsequent fuel L
damage or compromise of tiie fuel storage or building configurations leading to.
l radiological or criticality concems. The new racks have been analyzed in their i
L new configuration and found safe during seismic motion. Fuel has been determined to remain intact and the storage racks maintain the fuel and fixed L
poison configurations subsequent to a seismic event. The structural capability of l
the pool and liner'wlli not be exceeded under the appropriate combinations of dead weight, thermal, and seismic loads. The Fuel Building structure will remain l
Intact during a seismic event and will continue to adequately support and protect the fuel racks, storage array, and pool moderator / coolant. Thus, the consequences of a seismic event are not increased.
l' Fuel mistoading accidents were previously postulated occurrences. The l'
consequence of this type of accident has been analyzed for the worst possible storage configuration subsequent to the proposed modification and the consequences were found to be acceptable because the reactivity in the Spent l
Fuel Pool remained below 0.95. After the proposed modrficallon, the worst case postulated accident condition, for the Mixed Zone Tnree Region configuration,
- occurs when a fresh fuel assembly of the highest possible enrichment in F
inadvertently loaded into a Region 2 storage cell. Further, after the proposed j.
modification, the worst case postulated accident condition, for the checkerboard configuration, occurs when a fresh fuct assembly of the highest possible I
l enrichment is inadvertently loaded into an empty storage cell, in both postulated j
accident scenarios, credit is allowed for soluble boron in the water, and the I
Spent Fuel Pool reactivity is maintained below 0.95. Therefore, there is no increase in consequences due to the modification.
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Therofore, it is concluded that the proposed changes do not significantly increase the probability or consequences of any accident previously evaluated.
2.
The proposed charige does not create the possibility of a new or different kind of accident from any accident previously evaluated.
To assess the possibility of new or different Find of accidents, a list of the
= important parameters required to ensure safe fuel storage was established.
Safe fuel storage is defined here as providing an environment which would not
- present any significant threats to workers or the general public. In other words, L_
l meeting the requirements of 10 CFR 100 and 10 CFR 20. Any new events which would modify these parameters sufficiently to place them outside of the boundaries analyzed for normal conditions and/or outside of the boundaries previously considered for accidents would be considered a new or different i
accident. The criticality and radiological safety evaluations were reviewed to I
establish the list of important parameters. The fuel configuration and the existence of the moderator / coolant were identified as the only two parameters which were important to safe fuel storage. Significant modification of these two parameters represents the only possibHity of an unsafe storage condition. Once the two important parameters were established, an additional step was taken to determine what events (which were not previously considered) could result in changes to the storage configuration or moderator /ccolant presence during or subssquent to the proposed changes. This process was adopted to ensure that the possibility of any new or different accident scenario or event would be identified.
Due to the proposed changes, an accidental drop of a rack module during construction activity in the nool was considered as the only event which might represent a new or different kind of accident.
An installation accident of a rack dropping onto stored spent fuel or the pool floor liner is not a postulated event due to the defense-in-depth approach to be taken, as discussed in detail within Section 3.5 of the Licensing Report [ Enclosure I to the March 20,1998 letter). This approach is similar to that taken previously for lifting a pool gate with the Spent Fuel Pool Bridge Crane. A new temporary hoist and rack lifting rig will be introduced to lift and suspend the racks from the bridge of the Cask Handling Crane. These temporary lift items have been designed in accordance with the requirements of NUREG 0612 and ANS! N14.6 with respect to redundancy in load path or safety margin. The postulated rack drop event is commonly referred to as a " heavy load drop" over the pools. Heavy loads will not be allowed to travel over any racks containing fuel assemblies, thus a rack drop onto fuel is precluded. A rack drop to the pool finer is not a postulated event, since all of the lifting components (except for the Cask Handling Crane) either provide redundancy in load path or are designed with safety margins greater than a factor of ten. Nevertheless, the analysis of a rack dropping to the liner has been performed and shown to be acceptable. However, the question of a new or different type of event is answered by determining whether similar heavy loads have been carried over the pool. As stated above, pool gates have been previously lifted within the Spent Fuel Pool. The pool gate and the storage racks are both designated as " heavy loads" and the safeguards taken to preclude these accidents are similar. All movements of heavy loads over the poo! will comply with the applicable administrative controls and guidelines (i.e.,
plant procedures, NUREG-0612, etc.) Therefore, the rack drop does not represent a new or different kind of accident.
The proposed change does not alter the operating requirements of the plant or of the equipment credited in the mitigation of the design basis accidents. The proposed change does not affect any of the important parameters required to ensure safe fuel storage. Therefore, the potential for a new or previously unanalyzed accident is not created.
3.
The proposed change does not involvs a significant reduction in a margin of safety.
The function of the Spent Fuel Pool is to store the fuel assemblies in a subcritical and coolable configuration through all environmental and abnormal loadings, such as an acrthquake or fuel assembly drop. The new rack design must meet all applicable requirements for safe storage and be functionally compatible with the Spent Fuel Pool.
WCNOC has addressed the safety issues related to the expanded pool storage capacity in the following areas:
1.
Material, mechanical and structural considerations
' 2.
Nuclear criticality 3.
Thermal-hydraulic and pool cooling The mechanical, material, and structural designs of the new racks have been reviewed in accordance with the applicable provisions of the NRC Guidance entitled," Review and Acceptance of Spent Fuel Storage and Handling Applications". The rack materials used are compatible with the spent fuel assemblies and the Spent Fuel Pool environment. The design of the new racks preserves the proper margin of safety during abnormalloads such as a dropped assembly and tensile loads from a stuck assembly. It has toen shown that such loads will not invalidate the mechanical design and materiai selection to safely store fuelin a coolable and subcritical configuration.
The methodology used in the criticality analysis of the expanded Spent Fuel Pool meets the appropriate NRC guidelines and the ANSI standards (GDC 62, NIJREG-0800, Section 9.1.2, the "OT Position for Review and Acceptance of Spent Fuel Storage and Handling App!! cations," Regulatory Guide 1.13, and ANSI ANS 8.17). The criticality analysis for the Mixed Zone Three Region and/or L
checkerboard configuration confirms that the K,is maintained less than 0.95 without credit for the soluble boron in the Spent Fuel Pool. Calculations show that for the most severe accident condition, a soluble boron concentration of 500 ppm boron, in addition to the Boral contained in the racks, would be adequate to maintain the Ke less than 0.95. In accordance with NRC guidelines, the soluble boren in the Spent Fuel Pool may be credited in accident conditions. A minimum l,
7 boron concentration of 2000 parts-per-million (ppm)is maintained in the Spent Fuel Pool. The soluble boron in the Spent Fuel Pool will ensure that K,is maintained substantially less than the design limitations under all conditions.
The margin of safety for suberiticanty is maintained by having the neutron multiplication factor equal to, or less than,0.95 under all accident conditions, including uncertainties. This criterion is the same as that used previously to establish criticality safety evaluation acceptance and remains satisfied for all analyzed accidents.
The thermal-hydraulic and cooling evaluation of the pool demonstrated that the pool can be maintained below the specified thermal limits under the conditions of the maximum heat load and during all credible accident sequences and seismic events. The bulk pool temperature will not exceed 207 'F during the worst single failure of a cooling pump. Localized pool boiling is predicted to occur in the worst single failure of a cooling pump in the hypothetical worst case storage cell, immediately following the completion of a full-core discharge. This cellis very conservaWvely modeled to contain the hottest spent fuel assembly, with maximum flow resistance including 50% blockage of both the inlet and outlet flow areas. However, bulk pool boiling will not occur, nor will fuel cladding experience DNB [ departure from nucleate boiling] or excessive thermal stresses. The fuel will not undergo any significant heat up after an accidental drop of a fuel assembly on top of the rack blocking the flow path. A loss of cooling to the pool will allow sufficient time (2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />) for the operators to intervene and line up alternate cooling paths and the means of inventory make-up before the onset of pool boiling. Therefore the allowed operator action time remains unchanged from the previous design bases, in the unlikely event that all pool cooling is lost coincident with the completion of a full-core discharge, sufficient time will still be available subsequent to the proposed changes for the operators to provide an altemate means of cooling before the onset of bulk pool boiling. Therefore, the accepted margin of safety remains the same.
Thus, it is concluded that the changes do not involve a significant reduction in the margin of safety.
The NRC staff has reviewed the licensee's analysis and, based on this review, it appen that the three standards of 10 CFR 50.g2(c) are satisfied. Therefore, the NRC staff proposas to determine that the amendment request involves no significant hazards consideration.
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' 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.
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 l
failure to act in a timely way would result, for example, in derating or shutdown of the facility, i
l the Commission may issue the license amendment before the expiration of the 30-day notice l
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' period, provided that its final determination is that the amendment involves no significant i
hazards consideration. The final determination will consider all public and State comments l
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.
l Written comments may be submitted by mail to the Chief, Rules and Directives Branch, Division of Administrative Services, Office of Administration, U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, and should cite the publication date and page number of this FEDERAL REGISTER notice. Written comments may also be delivered to l
Room 6D59, Two White Flint North,11545 Rockville Pike, Rockville, Maryland, from 7:30 a.m.
to 4:15 p.m. Federal workdays. Copies of written comments received may be examined at the i
NRC Public Document Room, the Gelman Building,2120 L Street, NW., Washington, DC.
The filing of requests for hearing and petitions for leave to intervene is discussed below.
By August 12,1998, the licensee may file a request for a hearing with respect to issuancs 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 l
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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 s
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Commission's " Rules of Practice for Dornestic 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, NW., Washington, l
DC, and at the local public document room located at the Emporia State University, William l
Allen White Library,1200 Cornmercial Street, Emporia, Kansas 66801 and Washbum j
University School of Law Library, Topeka, Kansas 66621. 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 i
Licensing Board, designated by the Commission or by the Chairman of the Atomic Safety and j
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 CFR 2.714, a petition for leave to intervene sha!! 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 party to the proceeding; (2) the nature i
1 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
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of the Board up to 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 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 whien are sought to be litigated in the matter. Each contention must consist of a specific statement of the issue oflaw 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 expert opinion.
Petitioner must provide sufficient infonnation to rahow 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 amendrnent under consideration. The contention must be one which, if proven,
. would entitle the petitioner to relief. A petitioner who falls to file such a supplement which satisfies these requirements with recpect 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 i,;ervene, and have the opportunity to participate fully t
in the conduct of the hearing, including the opportunity to present evidence and cross-examine witnesses.
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.e.m 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.
h if the final determination is that the amendment request involves no significant hazaros mnsideration, the Commission may issue the amendment and make it immediately effective, notwithstanding the request for a hearing. Any hearing held would take place after issuance of tr. amendment.
If f"e final determination is that the amendment request involves a significant hazards consideration, any hearing held would take place before the issuance of any amendment.
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 20555-0001, Attention: Rulemakings and Adjudications Staff, or may be delivored to the Commission's Public Document Room, the Gelman Building,2120 'L Street, NW., Washington, DC, by the above date. A copy of the petition should also be sent to the Office of the General Counsel, U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, and to Jay Silberg, Esq., Shaw, Pittman, Potts and Trowbridge,2300 N Street, N.W., Washington, D.C.
20037, attorney for the licensee.
Nontimely filings of petitions for leave to intervene, amended petitions, supplemental petitions and/or requests for hearing will not be enterta!ned 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 specVied in 10 CFR 2.714(a)(1)(i)-(v) and 2.714(d).
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.12-The Commission herelcy provides notice that tnis is a proceeding on an application for a j
license amendment falling within the scope of Section 134 of the Nuclear Waste Policy Act of f 982 (NWPA),42 U.S.C.10154. Under Section 134 of the NWPA, the Commission, at the request of any party to the proceeding, must use hybrid hearing procedures with respect to "any l
matter which the Commission detennines to be in conroversy among the parties," The hybrid l
procedures in Section 134 provide for cral argument on mattsrs in controversy, proceeded by discovery under the Commission's rules, and the designation, following argument, of only those factual issues that involve a genuine and substantial dispute, together with any remaining questions of law, to be resolved in an adjudicatory hearing. Actual adjudicatory hearings are to
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be held on only those issues found to meet the criteria of Sect!on 134 and set for hearing after oral argument.
The Commission's rules implernenting Section 134 of the NWPA are found in 10 CFR Part 2, Subpart K," Hybrid Hearing Procedures for Expansion of Spent Nuclear Fuel Storage Capacity at CMilan Nuclear Power Reactors" (published at 50 FR 41670. October 15,1985) to 10 CFR 2.1101 sti ang Under those rules, any party to the proceeding may invoke the hybrid
. hearing procedures by filing with the presiding officer a written request for oral argument under 10 CFR 2.1109. To be timely, the request must be filed within 10 days of an order granting a 1
request for hearing or petition to intervene. (As outlined above, the Commission's rules in 10 i
CFR Part 2, Subpart G, and 2.714 in particular, continue to govem the filing of requests for a hearing or petitions to intervene, as well as the admission of contentions.) The presiding officer l
I shall grant a timely request for oral argument. The presiding officer may grant an untimely l
request for oral argument only upon showing of good cause by the requesting party for the failure to file on time and after providing the other parties an opportunity to respond to the
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l untimely request. If the presiding officer grants a request for oral argument, any hearing held on the application shall be conducted in accordance with the hybrid hearing procedures. In 1
essence, those procedures limit the time available for discovery and require that an oral argument be held to determine whether any contentions n. -t be resolved in adjudicatory hearing. If no party to the proceedings requests oral argument, or if all unt!mely requests for oral argument are denied, then the usual procedures in 10 CFR Part 2, Suboart G, apply.
l For further details with respect to this action, see the application for amendment dated l
March 20,1998, as supplemented by letter dated May 28,1998, which is available for public inspection at the Commission's Public Document Room, the Gelman Building,2120 L Street, 1
NW., Washington, DC, and at the local public document room located at the Emporia State l
University, William Allen White Library,1200 Commercial Street, Emporta, Kansas 66801 and 1
. Washbum University School of Law Library, Topeka, Kansas 66621.
Dated ct Rockville, Maryland, this 7th day of July 1998.
FOR THE NUCLEAR REGULATORY COMMISSION NM Kristine M. Thomas, Project Manager Project Directorate IV-2 Division of Reactor Projects Ill/IV l
Office of Nuclear Reactor Regulation I
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