ML21314A015
| ML21314A015 | |
| Person / Time | |
|---|---|
| Site: | 07109337 |
| Issue date: | 09/11/2021 |
| From: | Ashley Ferguson Croft Associates Limited |
| To: | Office of Nuclear Material Safety and Safeguards |
| Shared Package | |
| ML21314A013 | List: |
| References | |
| Download: ML21314A015 (7) | |
Text
3979A O-ring NCT Test Temperature Reduction -
SARP Impact Document Reference CTR 2021/22 Issue A Date 09/11/2021 File Name Document1 Client Reference Croft Associates Ltd T: +44 (0)1865 407740 F4 Culham Science Park F: +44 (0)1865 407449 Culham, Abingdon E: info@croftltd.com Oxon, United Kingdom W: www.croftltd.com OX14 3DB
3979A O-ring NCT Test Temperature Reduction - CTR 2021/22 SARP Impact Issue A Page i Document Verification Title 3979A O-ring NCT Test Temperature Reduction - SARP Impact Project Number Document Reference CTR 2021/22 Date 09/11/2021 Revision Issue A First issue.
Compiled Checked Approved Name A L Ferguson I Dingwall A L Ferguson Signature Revision Issue Date Basis and details of change Compiled Checked Approved Name Signature
3979A O-ring NCT Test Temperature Reduction - CTR 2021/22 SARP Impact Issue A Page 1 of 5 Figure 1 - Safkeg LS-3979A
3979A O-ring NCT Test Temperature Reduction - CTR 2021/22 SARP Impact Issue A Page 2 of 5 Contents 1 Introduction .................................................................................................................... 2 2 References .................................................................................................................... 3 Tables Table 1 - NCT Temperature Reduction - SARP 3979A Safety Impact Assessment ................ 4 Figures Figure 1 - Safkeg LS-3979A ..................................................................................................... 1 1 Introduction The Safety Analysis Report for Package (SARP) design No. 3979A contains a requirement to perform thermal ageing tests on batches of the O-ring seals procured for the Containment Vessel, as specified Chapter 8, section 8.1.5.2 of the SARP (CTR 2008/10: Docket No. 71-9337 [1]). This test requirement identifies two separate tests:
The temperature of the O-rings shall be maintained for 1000 hours0.0116 days <br />0.278 hours <br />0.00165 weeks <br />3.805e-4 months <br /> at 150°C to 155°C for the 150oC test or for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> at 200oC to 205oC for the 200oC test.
2 Change Proposal Due to material test repeatability issues, as identified and discussed in Test Report CTR 2021/24 [2], the NCT 1000 hour0.0116 days <br />0.278 hours <br />0.00165 weeks <br />3.805e-4 months <br /> 150oC test is to be reduced to 1000 hours0.0116 days <br />0.278 hours <br />0.00165 weeks <br />3.805e-4 months <br /> at a slightly reduced temperature, 130oC (with the test performed between 130 to 135oC), however, the HAC test requirement will remain unchanged.
3 SARP Temperature Impact Assessment The impact on the SARP assessment of reducing the NCT temperature test requirement is considered and assessed in Table 1, addressing each reference to the use of the 150oC seal temperature limit identified within the SARP and assessing its impact, if any, on safety functions.
The conclusion of the assessment performed is that there are no safety issues related to this change proposal, all assessments performed in the SARP employ bounding temperature limits in terms of structural, thermal, containment and pressure assessments.
The maximum NCT temperature assessed in the SARP was 116.4oC, therefore the temperature reduction continues to provide a safety margin over actual operating temperatures.
3979A O-ring NCT Test Temperature Reduction - CTR 2021/22 SARP Impact Issue A Page 3 of 5 4 References
[1] Croft, CTR 2008/10, Safety Analysis Report Safkeg-LS Design No. 3979A, Revision 7.
[2] Croft, CTR 2021/24, LS 3979A (3980) O-ring Seal, Issue A, 2021.
3979A O-ring NCT Test Temperature Reduction - CTR 2021/22 SARP Impact Issue A Page 4 of 5 Table 1 - NCT Temperature Reduction - SARP 3979A Safety Impact Assessment SARP Subject Reference NCT temperature reduction Safety Justification/Comments Section location Impact 2, Table 2-12 Mechanical Page 2-22 None, used to provide an upper bound The reduced NCT temperature range fits within the Properties of SA- on material properties. temperature range listed 320/A320 Grade L43 Bolting Steel 2.3.2 Examination. Page 2-24 None, the second paragraph describes The reduced temperature NCT test continues to provide a Material Tests the proposed tests safety margin over actual NCT temperatures 2.7.1.1 End Drop, Page 2-50, None, used to provide an upper bound The reduced NCT temperature range fits within the bounding Containment 2nd para on material temperatures. temperature range assessed.
Vessel Evaluation 2.7.1.2 Side Drop, Page 2-53, None, used to provide an upper bound The reduced NCT temperature range fits within the bounding Containment 2nd para on material temperatures. temperature range assessed.
Vessel Evaluation 2.7.1.3 Corner Drop, Page 2-56, None, used to provide an upper bound The reduced NCT temperature range fits within the bounding Containment 2nd para on material temperatures. temperature range assessed.
Vessel Evaluation 3.1.3 Summary Tables of Page 3-4 None, an arbitrary Containment vessel The reduced temperature NCT test of 130oC continues to Temperatures, lid seal seal material temperature limit provide a safety margin over actual NCT temperature of Table 3-2 Summary of 150oC is referenced in the last 116.4oC.
of Calculated column Package Temperatures with 10 W Internal Heat Load under NCT 3.1.3 Summary Tables of Page 3-5, None, discussed temperature The note references an upper NCT temperature of 150oC, Temperatures, Table note excursions above NCT during HAC. however, the HAC seal material test requirement remains the Table 3-3 Summary 1 same, test at 200oC (the most recent tests are reported in of Package CTR 2021/24 [2]).
Temperatures for HAC Thermal Test 3.2.2 Component Page 3-10, None, quotes manufacturers The reduced temperature NCT test of 150oC to 130oC Specifications 7th para temperature ranges continues to provide a safety margin over actual NCT temperature of 116.4oC.
3979A O-ring NCT Test Temperature Reduction - CTR 2021/22 SARP Impact Issue A Page 5 of 5 SARP Subject Reference NCT temperature reduction Safety Justification/Comments Section location Impact The subsequent leakage tests performed after the 1000 hour0.0116 days <br />0.278 hours <br />0.00165 weeks <br />3.805e-4 months <br /> NCT (and HAC) test are significantly more searching than manufacturers data.
3.2.2 Component Page 3-11, None, quotes an arbitrary upper The reduced temperature NCT test of 150oC to 130oC Specifications 1st para temperature limit of 150oC, much continues to provide a safety margin over actual NCT higher than actual NCT temperatures. temperature of 116.4oC.
4.1 Description of the Page 4-2, None, references an upper NCT The reduced temperature NCT test of 150oC to 130oC Containment 3rd para temperature of 150oC, but actual continues to provide a safety margin over actual NCT System, temperature is 116.4oC temperature of 116.4oC. The 200oC test continues to demonstrate acceptable performance at temperature excursions above 130oC, as reported in CTR 2021/24 [2].
8.1.5.2 Containment Page 8-3, None. This section lists the NCT and As noted in the above assessments, reducing the NCT seal Vessel O-rings 1st, 2nd and HAC seal material test requirement material test from 150oC to 130oC retails a sufficient safety 6th paras only, the revised NCT test temperature margin over actual NCT temperatures. As noted in CTR of 130oC for 1000 hours0.0116 days <br />0.278 hours <br />0.00165 weeks <br />3.805e-4 months <br /> ensures a 2021/24 [2], additional tests were performed at 140oC, reliable and repeatable material test. demonstrating that there are no potential failures just over the revised NCT temperature limit.