ML22112A135

C-10 Letter Regarding Refueling Cavity Water Seal

ML22112A135
Person / Time
Site:	Seabrook
Issue date:	04/05/2022
From:	Skibbee P C-10 Research & Education Foundation
To:	Justin Poole NRC/NRR/DORL/LPL1
Poole J, NRR/DORL/LPL1
References
Download: ML22112A135 (2)

Text

Safety for Citizens April 5, 2022 via electronic mail Justin C. Poole Project Manager, Seabrook Station U.S. Nuclear Regulatory Commission Washington, DC 20555-0001 Re: Seabrook Station - Refueling Cavity Water Seal

Dear Mr. Poole,

In C-lO's review of the most recent NRC Integrated Inspection Report (05000443/202100 4} dated February 10, 2022 we noted that the NRC identified a Green finding involving failure to properly evaluate structure s potentia lly affected by Alkali-Silica-Reaction (ASR}. The ASR degradation was identified and imprope rly evaluated in the reactor cavity pit area.

As you know, the reactor cavity pit area is a seismic category I concrete structure and is categorized as part of the containm ent internal structure (CIS). C-10 is concerned that the evaluatio n of ASR degradat ion in this area may non-conservatively neglect all potentia lly affected configurations.

For example, Seabrook is among the reactors that does not rely on an inflatable pneumat ic seal to provide a leak-tigh t barrier when the reactor cavity is filled with water during refueling outage.

Table 8-2 in NUREG/CR-4525, "Closeou t of JR Bulletin 84-03: Refueling Cavity Water Seal," June 1990 (ML20055E683}, indicated that Seabrook employs four concentr ic solid metal seals for its cavity seal. It is our understanding that this design has the advantage of being invulnerable to pneumat ic seal deflation that prompte d Bulletin 84-03. However, the design has the disadvantage of being more vulnerab le to physical geometr y changes, such as those caused by ASR degradation, impairing the fit-up during refueling.

As described in Section 6.2 of the Updated Final Safety Analysis Report for Seabroo k (ML02323A121),

"A neutron shield consisting of borated concrete, and which is integral to the permane nt reactor cavity seal ring, is installed around the reactor vessel refueling flange ... ". We contend that any concrete growth could deform the seal ring and impair its sealing function during refueling C-10 requests that NRC verify that NextEra's evaluation of ASR degradation in the reactor cavity pit area considers all potentia lly affected structures and explicitly addresses the potentia l impact on the refueling water cavity seal.

C-10 Research & Education Foundation / 11 Chestnut St. Amesbury MA 01913 /

www.c-lO.o rg (978) 465-6646

Page 2- C-10 Letter re Re: Seabrook Station - Refueling Cavity Water Seal On March 9, 2022 we forwarded our additional concerns to Christopher Newport, Senior Resident Inspector at Seabrook Station.

We appreciate your assistance in ensuring that this critical matter is an integral part of NextEra's and the NRC's inspection requirements.

Sincerely, Patricia L. Skibbee Patricia L. Skibbee C-10 Research & Education Foundation 11 Chestnut St.

Amesbury, MA 01913 978-465-6646 patricia.skibbee@verizon.net cc: Christopher W. Newport, Senior Resident Inspector C-10 Research & Education Foundation / 11 Chestnut St. Amesbury MA 01913 / www.c-lO.org (978) 465-6646