Guidelines for Nuclear Data Requestors

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The following material is provided to guide requesters in preparing their requests using the online nuclear data request submission template. A well-posed request is much more likely to encourage data providers to undertake measurement or evaluation activities designed to fulfill the request than would a poorly posed request. Previous attempts at maintaining data request lists, by the Nuclear Energy Agency (NEA) as well as other agencies, have tended to be less successful than they might have been in stimulating new research because so many of the listed requests were poorly defined and the stewardship of these request lists was inadequate. The current NEA Nuclear Data Request List (the "List") is designed to avoid both of these pitfalls. Co-operation from data requesters in adhering to the present guidelines will insure that their requests are well received by the data provider community and will contribute to enhancement of the credibility of the NEA Nuclear Data Request List.

Motivation for the present request list

The basic philosophy of the present List is similar to that of earlier lists, namely, to stimulate nuclear research that will lead to improved quantitative knowledge of important nuclear processes based on requests received from the nuclear science community.

Categories of requests

The requests found in the List of accepted requests fall into two broad categories: general requests and high priority requests. A record of satisfied requests is also maintained to measure progress toward fulfilling important requests received from the nuclear science community.

Nature of a request

An individual request for nuclear data should be sufficiently limited to enable a well-focused research activity to be initiated. Generally, this will mean that a request should involve a single target nucleus, one reaction process, and a well defined energy range. Requests that are too broad will not be included in the List.

Example of a reasonable request

Measure the neutron fission cross section for 238U from 0.5 MeV to 8 MeV to an accuracy of 5% from 0.5-2 MeV, 3% from 2-5 MeV, and 4% from 8-10 MeV (other details need to be included as requested by the template).

Example of an unreasonable request

Measure the neutron fission cross sections of 235U, 238U, and 239Pu from thermal to 100 MeV to 1%. The latter request is unreasonable for several reasons. It involves more than one target isotope. The energy range is so broad that a number of distinct measurement techniques would need to be used, thereby making it unlikely that any individual research team could address the request in its entirety. Finally, the requested accuracy of 1% is probably unreasonable, especially when applied to such a broad energy range. The NEA will be guided by such considerations in selecting requests to include in the List. Thus, a requester will have a better chance of having his (or her) request accepted without severe modifications if the initial request is reasonable. In the latter case above, the single request should be broken up into several distinct requests corresponding to different isotopes and energy ranges, and more realistic target accuracies should be specified.

Who can submit requests?

Requests for improved nuclear data may be submitted by any members of the broad nuclear science community who possess knowledge of the data issue that gives rise to the request, and who can provide the information required to complete the data request submission template. It is anticipated that most of the requests received by the NEA will be from the data user community, and that these requests will be associated with specific contemporary nuclear science and technology projects. In particular, it is anticipated that most requests that fulfill the requirements for inclusion in the List as high priority requests will come from the user community because of the extensive documentation that must be submitted to justify the need and establish the impact of satisfying a particular request. However, data evaluators are also in a good position to identify data needs and deficiencies because, by its nature, the evaluation process requires detail review of the status of the database for the evaluated physical quantities. Most evaluators are familiar with at least a few of the important contemporary nuclear science and technology projects, and thus are qualified to offer reasonable justification for requested data. Requests from evaluators are more likely to be considered as general request candidates unless the request can be further substantiated by data user input. Requests from data measurers may be considered; however, because of the potential for a conflict of interest, such requests are likely to be referred to data evaluators and potential users for comments prior to seriously considering the request for acceptance into the list.

Important notice

Each request is submitted by an individual who will be considered as the "owner" of the request and the person to be contacted on all matters related to this request. Multiple requestors are permitted, but one individual will be considered the owner. Orphaned requests will automatically be eliminated from the List if no one can be found to adopt the request as a new owner.

How should requests be submitted?

Requests for improved nuclear data should be submitted using the data request template provided at this website.

How will a submitted request be processed?

Submission of a request does not automatically insure that the request will ultimately be included in the list

Requests that are properly prepared using the data request template will be assigned to a submission list and then referred to Subgroup C of the NEA Working Party for International Evaluation Cooperation (WPEC). This standing subgroup consists of two nuclear data specialists (one each from the data user and data provider communities) from each of the major data evaluation projects: U.S. (ENDF), JEFF (European Community), JENDL (Japan), and BROND (Russia). The request will then be carefully reviewed as soon as possible by members of Subgroup C. If the expertise required to comment upon a particular request is not available within the core subgroup membership, then the request will be referred to one or more consultants who are technically qualified to comment on the request. It is anticipated that during this process there will be communication between Subgroup C and the individual who submits the request in order to clarify certain details or to provide missing information. Requests that are very poorly posed may be returned to the requester without further consideration, or Subgroup C may decide that further discussions with the requester would be in the best interests of the nuclear science community. Subgroup C has the sole discretion as to how received requests are to be handled. When a final decision has been made by Subgroup C concerning a particular request, then that request will either be rejected or included in the List with a designation of either General or High Priority. In any event, the requester will be notified concerning final disposition of his (or her) request.

Stewardship of the request list

The NEA Nuclear Data Request List is a living entity that will be subject to periodic review. An objective of the NEA data request project is to review all listed requests periodically, perhaps as often as once a year. In any event, high priority requests will definitely be reviewed at least annually to monitor progress. Requests that have been satisfied will be transferred to the category of satisfied requests. Requests that are no longer relevant will be removed entirely. It is also the responsibility of the data requester to monitor the status of his particular request(s) and to inform Subgroup C of any changes in the status of any requests for which he (or she) is responsible. Closer cooperation and communication between requesters and Subgroup C will insure that the NEA List maintains currency and credibility, and serves its purpose to stimulate research aimed at satisfying individual requests.


The NEA has established an e-mail communications list to facilitate communication between data users, data requesters, data providers, staff members of the NEA, and members of Subgroup C. Messages can be posted to this list by sending e-mail to Communications addressed in this manner will be received by the NEA and distributed to a mailing list that includes Subgroup C members as well as several other interested individuals.

Layout of NEA Data Request List website

The information associated with each individual request will in most cases be too extensive to include conveniently in a spreadsheet-type format. Thus, a separate webpage will be produced for each included request from the List database. In addition, a spreadsheet-type table will be generated in response to each website viewer's specific needs. This table serves as an index and it includes only a portion of the total information available for any individual request. The detailed information for a particular request can be generated on demand by clicking on the request identification number.

Components of a data request

When a request is submitted using the online template, specific instructions related to individual fields of the entry form can be obtained by clicking on the field title. This includes codes and other details to help the requestor to prepare his (or her) request in accordance with the established formats and procedures. This section discusses in more general terms the various components of an individual request to aid the requester in understanding the underlying context of the information requested by the request template. Only those components marked with an asterisk ("*") need be supplied by the requester. Other information that appears in an accepted request in the List is provided by the NEA or Subgroup C.

Request identification (ID):

This is a unique number that identifies an individual request. This number will be assigned by the NEA upon receipt of the request via the online request template. The number will remain with the request throughout the review and listing process. If the request is denied, the number will automatically be retired. Similarly, a request number will be retired if a List request is deleted later for any reason. The data requester need not worry about supplying or managing this number.


An individual request should address a single target isotope, e.g., 12C. This should be consistent with the Z and A entries described below (redundancy presents no problems and is frequently convenient for readers who scan the List).


Atomic number of the target isotope, e.g. 6 for carbon.


Atomic mass number for the target isotope, e.g., 12 for 12C.


This field defines the physical reaction or process which is of concern to the requester. This might include neutron fission, neutron capture, delayed neutron emission, etc. The requester is prompted to enter the appropriate code for the reaction or process in question. Code symbols are provided through links from the request template.

Energy range*:

This field establishes the energy range of interest for the request. This corresponds to the energy of the incident particle in the laboratory system. It is important that the appropriate units be included as well, e.g., 10-150 keV.

Angle/secondary energy*:

If differential or double-differential data are requested, then the energy and angular ranges for the emitted particle need to be specified, e.g., 0.5-5 MeV emitted laboratory neutron energy over the laboratory angular range 0-135 degrees.

Requested accuracy*:

This is the requested accuracy (in %) for the physical quantity to determined. There are several points to keep in mind. First, unrealistic accuracy specifications will generally lead to rejection of a request. Even if a very high accuracy is truly needed, Subgroup C will be inclined to question why this is the case, and most probably will conclude that such a request is not likely to be fulfilled anytime within the foreseeable future and thus the request should not appear on the List where it could possibly remain indefinitely without being addressed. Second, rarely does a single accuracy number (e.g., 3%) apply over a broad energy range. Thus, a reasonable request for data over a fairly wide energy range should include a list of accuracy specifications in tabular form that correspond to distinct sub-components of the overall energy range of the request (refer to the section "Nature of a request" above). If it is evident to Subgroup C that the requester is submitting a legitimate request, but is not aware of the limitations that would be faced by providers of nuclear data who might attempt to satisfying such a request, it will most likely interact with the requester in order to reformulate the request in a manner that involves more reasonable accuracy specifications.


If a particular request involves specifying a collection of energy and/or angular ranges (possibly with varying accuracy requirements), that taken together comprise the whole request, then uncertainty correlation information may be required. If so, then the requester should state that covariance data are to be included in the request and provide some details. If there is no request for covariance information, then it will be assumed that knowledge of the variances (or standard deviations) alone is adequate.


A check-box allows the requester to tell if the request is intended to be of high priority or as a general request.

Application area*:

Due to the limited resources of the data provider community, worldwide, priority consideration will be given to requests that are known to be important for specific contemporary application areas, e.g., Generation IV reactor development, nuclear fusion, LWR pressure vessel surveillance, criticality safety, etc. For this reason, the requester is asked to provide this information in the appropriate field of the data request template. This is mandatory for requests intended to be of high priority.


A request from a data user will most likely be associated with a specific project. The relative importance and currency of such a project will be a factor in deciding whether a request should be general or high priority. In some cases, a request may originate for a more fundamental reason, e.g., an evaluator determines that he (or she) will be able to better define particular nuclear model parameters if certain experimental data that currently do not exist were available. This might constitute a legitimate request that is not associated with any specific technology project but that is nevertheless important for fundamental reasons.

Important notice


The end date of the associated project for when the requested data is needed is to be stated in the request.

Justification documentation*:

This is the heart of any request for nuclear data. The requester is expected to make a strong case as to why the request is being submitted. The need for these data, inadequacy of existing information, etc., should be clearly established. In the case of requests that are to be considered as general, a few sentences (or paragraphs) with reference to documents that establish the current status of these data would probably be sufficient. In the case of requests that are intended to be high priority, much more extensive documentation is required to justify a high status for the request. This documentation might be a report or journal article that clearly shows the importance of the requested data, in quantitative terms, and establishes the lack or inadequacy of such data. If possible, an electronic version of this report - or a link to the report elsewhere on the Internet - should be transmitted to the NEA along with the request. Requests intended to be of high priority will be subjected to considerable scrutiny by Subgroup C, and they will be included in this category only if there is a firm consensus by experts in the field that this would be appropriate. Quantitative support for a request, especially for specified accuracy levels, can usually result only from sensitivity studies. To requestors who might object to such stringent requirements for high priority requests, Subgroup C responds by noting that if a request is really to be of high priority, and the need for the information is great, then it is likely that the project requesting the data will have already performed such analyses and reached conclusions concerning the importance of the data from this work. If these analyses have not been performed, then Subgroup C must conclude that the requirement is not sufficiently strong to motivate such an investigation and therefore is probably not of very high priority.

Impact documentation*:

The justification for a request establishes the need for the requested data. However, the impact that having such information - if indeed it is possible to satisfy the request - must be established by impact documentation submitted along with the request. The requirement for detailed quantitative information on impact to support a particular request for data is again much more severe for high priority requests than for general requests. Generally, impact deals with matters such as safety, reliability, and cost. For example, if the requester can make a case that better knowledge of a neutron activation cross section (to within specified accuracy limits) could lower the cost of storing radioactive waste by significant amounts, this would qualify as strong support for the request on the basis of cost impact.

General comments*:

Any general comments can be given here. That can for example be if references or documents are to be attached as justification of the request. (the NEA will in such a case ask for these files in a separate email.)


Each request should be "owned" by a single individual. Multiple requesters can be permitted, but one will be the main contact person. Organizational affiliation, contact details (mailing address, telephone, e-mail address) must be entered in the request. template.


The date when the request was initially submitted via the template as well as the date posted on the List following review and approval will both be established by the NEA for each individual request.

Country/International Organisation*:

The country or international organisation from which the request is initiated is specified, e.g., France, IRMM, IAEA, etc.


A field is provided in the request template to allow any additional information that the requestor feels is pertinent to be submitted as part of the request. This information should be added in text form, and links to information available elsewhere on the Internet, or references to the literature, can be included if this is deemed to be useful


The submitter of a request need not be concerned with this field, so it is not part of the request form. All ancillary information related to this request will be included here, or there will be links or references to such information if it can be found elsewhere. This provides a mechanism for the nuclear science community to comment on requests found in the List and to have these comments made available to the public via the website.

Status (present accuracy, on-going activities, etc.):

In its review of a particular request, Subgroup C and its consultants may generate comments that are pertinent to this request. These will be included in the website.

Subgroup C assessment:

Comments from Subgroup C concerning the prognosis for satisfying the listed request will be included in this field. Again, there may be links or other references to supportive information.