---
title: "Provision of ANSWERS/FISPIN Nuclear Software Codes"
ocid: "ocds-h6vhtk-06e816"
canonical_url: "https://d3tenders.com/contract/?ocid=ocds-h6vhtk-06e816"
markdown_url: "https://d3tenders.com/contract/ocds-h6vhtk-06e816.md"
json_url: "https://d3tenders.com/contract/ocds-h6vhtk-06e816.json"
source: "Find A Tender Service"
current_stage: "Award"
buyer: "UNITED KINGDOM NATIONAL NUCLEAR LABORATORY LIMITED"
published: "2026-08-19"
---

# Provision of ANSWERS/FISPIN Nuclear Software Codes

Buyer: UNITED KINGDOM NATIONAL NUCLEAR LABORATORY LIMITED  
Current stage: Award  
OCID: ocds-h6vhtk-06e816

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## Summary

United Kingdom National Nuclear Laboratory Limited procured renewal of licences for the ANSWERS/FISPIN nuclear software suite. The requirement covers specialist nuclear safety analysis, criticality assessments, radiation transport, shielding calculations and reactor physics modelling. The package also includes software maintenance, updates and technical support, supporting established analytical methods, validated models and regulatory-approved nuclear safety case activities. This is a software and information-systems requirement, delivered for UKNNL’s activities in the United Kingdom. The buyer is a public authority based in Warrington. The requirement suits software providers with specialist nuclear engineering products, particularly tools used in safety analysis and reactor physics, rather than general-purpose software suppliers.

The procurement has been awarded through a completed single-lot process. UKNNL used a direct award without prior publication, relying on the absence of competition for technical reasons and identifying Energy, Safety and Risk Consultants (UK) Limited as the only capable supplier of the proprietary ANSWERS/FISPIN suite and associated support. The award date was 19 August 2026. The award value is £603,312 excluding VAT, or £723,974 including VAT. The awarded contract period runs from 1 September 2026 to 31 August 2029, with signature scheduled for 1 September 2026. The stated rationale is that alternatives would require substantial revalidation, regulatory approval, retraining and programme disruption. The award covers the complete lot.

This procurement demonstrates demand for proprietary or highly specialised nuclear modelling software embedded in validated safety and engineering methodologies. A credible competitor for a future requirement would need demonstrable capability in nuclear safety analysis, criticality assessment, radiation transport, shielding and reactor physics modelling, together with software maintenance, controlled updates and technical support. Experience of supporting regulatory-approved processes would be particularly important, as would the ability to work within established analytical methods and models without creating unacceptable revalidation, training or programme risks. Suppliers would need sufficient technical depth and support capacity to serve a national nuclear laboratory, maintain continuity of complex software use and provide assurance suitable for nuclear safety case activities.

## Notice

This contract is for the renewal of licences for the ANSWERS/FISPIN nuclear software suite, including specialist codes used for nuclear safety analysis, criticality assessments, radiation transport, shielding calculations, and reactor physics modelling. The software supports established analytical methodologies and regulatory-approved processes across UKNNL's nuclear modelling and safety case activities. The contract provides software licences, maintenance, updates, and technical support for a period of three years.

### Procurement Information

The contracting authority intends to award the contract without prior publication due to the absence of competition for technical reasons. The ANSWERS/FISPIN software suite is proprietary and is only available from Energy, Safety and Risk Consultants (UK) Ltd. The software is embedded within existing UKNNL analytical methodologies, validated models, and regulatory-approved processes. There are no reasonable alternative solutions capable of meeting the contracting authority's requirements without significant revalidation, regulatory approval, retraining, and disruption to ongoing nuclear safety and engineering programmes. Replacing the software would result in substantial additional cost, programme delay, and technical risk. The supplier is therefore the only economic operator capable of providing the required licences and associated support services.

## Key Details

| Field | Value |
| --- | --- |
| Publication source | Find A Tender Service |
| Latest notice | https://www.find-tender.service.gov.uk/Notice/079231-2026 |
| Notice type | UK5 - Transparency Notice |
| Procurement type | Standard |
| Procurement category | Goods |
| Procurement method | Direct |
| Procurement method details | Direct award |
| Tender suitability | Not specified |
| Awardee scale | Large |
| All stages | Award |

## Dates

| Field | Value |
| --- | --- |
| Publication date | 19 Aug 2026 |
| Submission deadline | Not specified |
| Future notice date | Not specified |
| Award date | 19 Aug 2026 |
| Contract period | 1 Sep 2026 - 31 Aug 2029 |
| Recurrence | Not specified |

## Values

| Field | Value |
| --- | --- |
| Tender value | Not specified |
| Lots value | Not specified |
| Awards value | £603,312 |
| Contracts value | Not specified |

## Status

| Field | Value |
| --- | --- |
| Tender status | Complete |
| Lots status | Complete |
| Awards status | Pending |
| Contracts status | Not specified |

## Buyer

| Field | Value |
| --- | --- |
| Main buyer | UNITED KINGDOM NATIONAL NUCLEAR LABORATORY LIMITED |
| Locality | WARRINGTON |
| Postcode area | Warrington |
| Postcode | WA3 6AE |
| Country | England |
| ITL 1 | TLD North West (England) |
| ITL 2 | TLD6 Cheshire |
| ITL 3 | TLD61 Warrington |
| Local authority | Warrington |
| Electoral ward | Birchwood |
| Westminster constituency | Warrington North |
| Delivery location | Not specified |

## Supplier

| Field | Value |
| --- | --- |
| Number of suppliers | 1 |
| Supplier names | ENERGY, SAFETY AND RISK CONSULTANTS (UK) LIMITED |

## CPV Codes

### Divisions

- 48 - Software package and information systems

### Codes

- 48000000 - Software package and information systems

## Release History

- 19 Aug 2026 at 19:37 - Award - UK5 - Transparency Notice - https://www.find-tender.service.gov.uk/Notice/079231-2026

## Documents

- https://www.find-tender.service.gov.uk/Notice/079231-2026
  19th August 2026 - Transparency notice on Find a Tender

## Notice URLs

- http://www.amentum.com
- http://www.uknnl.com
- https://www.legislation.gov.uk/ukpga/2023/54/contents

## Provenance

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