ML17097A242

Comment (7) of Hans Gougar on Behalf of Nuclear Energy Institute on on Guidance for Developing Principal Design Criteria for Non-Light Water Reactors

ML17097A242
Person / Time
Site:	Nuclear Energy Institute
Issue date:	04/04/2017
From:	Gougar H Nuclear Energy Institute
To:	Cindy Bladey Rules, Announcements, and Directives Branch
References
82FR9246 00007, NRC-2017-0016
Download: ML17097A242 (42)

Text

Duran-Hernandez, Doris

Subject:

FW: CCN 240165 Response to Request for Public Comments Regarding:

"Guidance for Developing Principal Design Criteria for Non-Light Water Reactors," Draft Regulatory Guide DG 1330, Docket ID NRC-2017-0016 Attachments: CCN 240165 ARDC Reg Guide Comments.pdf; DOE-National Lab Team Comments on NRC Draft Reg Guide DG-1330.pdf From: Russell, Diana E [1]

Sent: Tuesday, April 04, 2017 4:11 PM To: Bladey, Cindy <Cindy.Bladey@nrc.gov>

Cc: tom.oconnor <tom.oconnor@nuclear.energy.gov>; trevor.cook@nuclear.energy.gov; Clifford P.

Fineman <finemacp@id.doe.gov>; Mazza, Jan <Jan.Mazza@nrc.gov>; Reckley, William

<William.Reckley@nrc.gov>; Cubbage, Amy <Amy.Cubbage@nrc.gov>

Subject:

[External_Sender] CCN 240165 Response to Request for Public Comments Regarding:

"Guidance for Developing Principal Design Criteria for Non-Light Water Reactors," Draft Regulatory Guide DG 1330, Docket ID NRC-2017-0016 This is the electronic distribution for CCN 240165, Response to Request for Public Comments Regarding: "Guidance for Developing Principal Design Criteria for Non-Light Water Reactors," Draft Regulatory Guide DG 1330, Docket ID NRC-2017-0016. The referenced enclosure is also attached.

If you have any questions regarding the comments provided in the enclosure, please contact Jim Kinsey, Regulatory Affairs Director at (208) 569-6751.

Diana Russell a/3/r:/C)I 7 Administrative Assistant Idaho National Laboratory g~~7~4 Phone: 208-526-8025 :0 ~ '-l.....~  ;::.::.:

1"'~

n1

('""""'\

f"r

'**~ )  ;

r*r1 "-...l'l:

.:*i,

<

• .q ""' *'

rn .....::.-

Y.1 0 a

• -......i e~J SUNSI Review Complete

=

Template ADM - 013 E-RIDS= ADM-03 Add= '-1Jl. Orr &1'~,z,) 1

/

April 4, 2017 CCN 240165 Cindy Bladey Office of Administration U.S. Nuclear Regulatory Commission Mail St9p: OWFN-12-H08 Washington, DC 20555-000 l

SUBJECT:

Response to Request for Public C01mnents Regarding: "Guidance for Developing Principal Design Criteria for Non-Light Water Reactors," Draft Regulatory Guide DG-1330, Docket ID NRC-2017-0016

References:

(a) "Guidance for Developing Principal Design Criteria/or Advanced (Non-Light Watcu~ Reactors," INL/EXT-14-31179, Revision l, December 8, 2014 (b) "Guidance for Developing Principal Design Criteria/or Non-Light Water Reactors," Draft Regulatory Guide DG-1330, U.S. Nuclear Regulatory Comm.ission, Docket ID NRC-2017-0016

Dear Ms. Bladey:

In July 2013, the U.S. Department of Ene1*gy (DOE), Office of Nuclear Energy (NE), and U.S. Nuclear Regulatory Commission (NRC), Office of New Reactors (NRO), agreed to establish a joint initiative to develop a key element of a licensing framework for advanced non-light water reactor (non-LWR)

-- technologies by agreeing to pursue an initiative to address the "General Design Criteria (GDC) for Nuclear Power Plants," Appendix A to 10 CFR Part 50> relative to licensing advanced reactor designs.

DOE, with support from selected national laboratories and consultants, completed the first phase of this effort which culminated in the development of a series of proposed adaptations to the GDC that could be used as input for NRC staff development of regulatory guidance. The results of that effort are reflected in the Idaho National Laboratory (INL) technical report, Guidance for Developing Principal Design Criteria for Advanced (Non-Light Wate1'l Reactors.

The second phase of this initiative consisted ofNRC's efforts to review the recommendations regarding proposed advanced reactor design criteria and to develop regulatory guidance on how the GDC in Appendix A apply to non-L WR designs. This guidance may be used by non-L WR designers, applicants, an.d licensees to develop principal design criteria for non-LWR designs. The draft regulatory guide also describes NRC's proposed guidance for modifying and supplementing the GDC to develop principal design criteria that address two spedfic non-L WR technologies: sodium-cooled fast reactors (SFRs) and modular high temperature gas-cooled reactors (MHTGRs).

P.O..Box 1625

• 2525 North Fren;iont Ave.

• Idaho Falls, Idaho 83415

• 208-526-0111

• www:inl.gov

- - - - - - - - - - - - Battelle Enerov Alliance. LLC - - - - - - - - - - - -

/

Cindy Bladey April4,2017 CCN240165 Page2 The purpo~e of this letter is to transmit the DOE/national laboratory teart?- comments (see enclosure) regarding DG-1330 to NRC for consideration during the public comment review period in support of updates and issuance of the regulatory guide. DOE continues to support NRC in its development of NRC-issued regulatory guidance that provides increased clarity and certainty for advanc.ed reactor developers and future license applicants and appreciates the NRC stafrs efforts in this area. For example, proposed ARDC 17 content regarding electric power systems provides increased clarity and flexibility for designers and license applicants as they pursue enhanced margins of safety and the use of

• simplified, inherent, passive, or other innovative means to accomplish safety and security functions consistent with the Commission's policy ort advanced reactors.

If you have any questions regarding the comments provided in the enclosure, please contact Jim Kinsey, Regulatory Affairs Director at (208) 569-6751.

Sincerely,

~t/tu.-Jf"--

HansGougar Co-National Technical Director Advanced Reactor Technologies I

Enclosure, "DOE/National Laboratory Team Comments on Draft Regulatory Guide DG-1330," March 2017 cc: DOE-HO T. J. O'Connor, tom.oconnor@nuclear.energy.gov T. Cook, trevor.cook@nuclear.energy.gov DOE-ID M. L. Adams (w/o Enc.), adamsml@id.doe.gov C. P. Fineman, finemacp@id.doe.gov INL J. Alvarez (w/o Enc.),juan.alvarez@inl.gov .

\.

NRC J. Mazza, jan.mazza@nrc.gov W. D. Reckley, william.reckley@nrc.gov A. Cubbage, amy.cubbage@nrc.gov

DOE/National Laboratory Team Comments on Draft Regulatory Guide DG-1330 Docket ID NRC-2017-0016 Positive Comments

,,~0~$,~J,~!iL;Fi*; *'*> '*' '  :.* .Pnge Regulatory*GuidcText ',,

.P!)sitiye Team Cont.!uenti,;

Appendix A A-7 ARDC 26: R~twtMty <~mtml systems. Tho mi!{inul GDC 26 lan!luagc wus tmn<'Cessnrily confosing and tho Appendix B 0-9 Reactivity control S)'Stcms shnll include tho followins cupubilitios: stnfrs proposed revision of ARDC 26-27 oilers !lr<'l1ter clarity of Ap1wndixC C-11 underlying snfcty intent. Gcnerully spcakin1:1. the tcnm a1:11ws thnt the (I) A mcnns ofshuuin11 down the Nnctor slmll be pl'Ovidcd'to ensure revised structure of AROC 26 is u signifktmt improvement.

thut. under contlltions ofnonnal operation. including anticiputed operational occmwnccs, and with np11roprlatc nmrsin for This positive comment also applies to the corr<-sponding SFR-DC 26 nnd malfunctions. dcsisn limits for fission product bnrriers m'll not mllTOR-DC 26.

cxccodcd.

(2) A meuns ofshuttins down the reuctQt' and nmintaining a safu shutdown under dcsi!ln*hasis event conditions. with npproprlatc mnrsln for malfimctlons. shnll be pro\'idod. A second mcnns of 1vnctMI)' control shnll be pt'IJ\*ided thnt Is independent. diwri;c.

nnd capable ofnehle\'in!). nnd mnlutninin!l safo shutdown under desl!).n-bnsis event condition~

(3) A system for holdhi!). the 1vnctor subcl'itlcnl tnuler cold conditions shnll be nrovided.

Appendil\A ARDC 17: llYc<<ll'lo pmi*e1* .~twtems. The temn commends tho NRC for this criterion ndnptutlon. The fllcctrlc powc1* systems shall be pl'<widixl to permit 11.mctioning of uda11tation provides increnscd tlcxibility fo1* designers und license structures, systems. nnd components impo11nnt to snfety. The snfoty u11plicnnts ns they pursue enhnnc<'CI mnrgins ofsnfoty und the use of l\mction for the systems shnll be Ill pro\'ide sntlicicnt ct1padty, simplified. inherent. pnssivc. or other innovative means to nccomplish cnpabili~y, nnd relinbility to ensure that (I) s1m:ifa'CI ncccptnble fuel safety nnd security functions. consistent with the Commission's policy on design limits nnd design conditions of the t'llnctor coolam bonndnl)' nre ndvnncixl reactors.

not excecdl'CI us n 1'\lsnlt ofnnticlputod Q)lcrntionnl O<'CUrrcnccs and (2) vital 11.mctions tlmt rely on electric power arc maintained In tho This positive comment also npplies to the corresponding SFR-DC-17 and ownt ofpostulnt<'CI nccidcnts. modular HTGR-DC-17.

The onsitc electric power s)*stoms shnll hnvo sufficient independence, redundancy. and testnbility to perform their snfoty fnnctiQnS. assuming a sinulc failure.

Appendi~ C C-3 mltTGR-DC-10 Rcmctorclcslg11 The NRC stnfrs incorporution of tho SARRDL ns n roplncemcnt for the SAFDL is a very important step forward in the development of the modnlnr HTGR dcsiun criteria, PPE/Nglionul Luborutory Tcm11 Comments on DrnO Regulatory Gujdo OG-1330 *Docket m NRC-2017-0016: Pugc I

Page< Regulatory Gui.de Text P9sitJvcTeam.Comments Appendix C mHTGR*DC 14 /IQ<Wf(;r hcl/11m pN.*s11rc hotmdury Rntlonule: flor The addition of the 1-eforence to modular HTOR DC 30. and the consistenc;.-. a spooilic. requiremcnt Is ap1wndcd to mHTGR DC 30 for ti ussocinted chnnl.l<CS to modular HTGR Cl'itel'in 14 mid 30, ure both means ofMt1.'Ctln1,1 ing1-ess ofnmisture, nlr. sooondmy coolant, or QthQI' excellent imprnvements.

fluids. Although "other fluids could be interp1-etcd as including wntcr nnd steam. for emplmsis, the word nmlsture" Is included in the list of contmnlnants In both mHTGR DC 14 nnd mHTOR DC 30.

mllTOR*DC* IS llem'lfw lmlimn p1'1'ss111\' h1111mlm~* d~slgn The clmnges to Ilic text In the body of this criterion mndc by the NRC stnffrelatlvtJ to the pmposed text In the DOE/INL report arc nn imnrm*ement.

C*l4 mHTGR*DC 28 RrtwtMty //111/ts Rationule: The list ot)mst11lnted The deletion of tho Hst ufpostuluted reactivity accidents. lenving ench t'llacHvlty accidents" hus b..wn deleted. llnch dflSlgn will huve to desiyn tu detemilnc its list of postulated 1-enctiYit~* uccidents. is a >>ery determine Its postulat\ld renctlYlty accidents bused on the s11eellic good change.

desi!m nnd ussodnted t'lsk e\'uluution.

Appendix C C*lS mHTOR*DC 30 (11111//~)' 1:!f1ww101* iWl/11111 pro,~*111'1' hu111Kl11~y: Menns Th<.' NRC. stnfrs addition of the lust seutencQ to this critol'lon is mt shall be prtwldcd fo1* detecting h1g1'\lss ofmoist111'\\ air. secondary excellent impt'Ovement.

ooolm1t, or other tlllids to within the r1mctor helium 11ress11re bmmdm;*.

DOE/Nqtionu! Lpbornton* Tt:am Comments on DrnO R1rnulatory Gyjdo DG-1330 *Docket JD NRC-2017-*0016: Page 2

General Comments on the Report Section of Draft Regulatory Guide DG-1330 Docket ID NRC-2017-0016

c;..t;:~.~*;.w :.*,. *:.>.' .. ..

.';,:;,--*" ****".'.c>: > , Pngo***.

• Rogulnton*,Guido.Toxt . ' . Ten,nc<;ommonts  :

Related GuidanQe, ~ Tl1Q dmit t'tlgulmmy !,lUkte h1Qludos tho fullowln!! cltatlon ln its ThQ NGNP lntemetions did not include NRC rt.wiew ofn specific Communications. nmt Policy "Related Ouidnnce. C'mmmmicatlons. und PQllcy Stntomonts" listing: modular HTGR "design", but mthe1* n series ofproposnls to nddress Stutements NRC, "Nm*t Gmwmtlon N11cl(!lll' f/(1111 * ,.J,11.11'.l\l'llWlll t!fl\<!y llw11.~l11g policy and key technical issues associated with mHTGR technolo!l)'. The lss1ms, "tiflt<!d J11I)' /7, JON. p1vwldtw tilt! NRC ,\'l<tfl~~ l'<'l'it'll'<llld wonl "d(!s/g11" should l>e deleted und l'tlplnced with *~imposed li<x*11sl11g 111.~l!!ll/.\' 0111/le N(!X/ Gt>tt(!ml/1111N1wlt'ar1'1<11111111/TGR i/(!s/Jm tR~J: I I). (IJ>Jltlll/Ch,"

Role ofODC in Reg.ullltory (\ The dmt\ res11lnto1;* guide states: "The GDC'm'<' 11l-w1/111<'111k~l111 Ou1* undQratundins is thnt SSC snfoty functions nre only t'lllied on during l'rnmework prov/I/<' g11ldu11t't' 111 es111h/l,d1i11g tM PDC:.fiw llflll*lll'Rs. Tiie GDC plant responsll to postulnted accidents. This scntoncQ, whkh also 1'tlfors to

.<e1*1*e £/,\' tMf11rnl11111ei1111I t*1*lwrlt1,/iw llw NRC' .~1qjf'wliu111wioll'l11g the normnl opem1ions and AOOs. should ho revised t() moro clearly Nllcct SSCs tl111111111ke Ill' '1111Wleor /lflll'lll' plant d?.~i/!.ll J>tll'lk11larly 11'/IQ11 this. A Sllll!lCSted l'llvision is to chnnge "snfoty functions" to "intended a.11.1'<'.~SlllJ! tlw pe1.1imnmwq *!flMlr .w1f&(vfi11wtl1111s l11 ileslg11 /u.1sl.1* t\mctions".

Q\'<'lllS l)(l,\'tlllUIQc/ tfl fW<!lll' dlll'itW l/fll'nt(ll OJl<'IYlliOllS, <1/11/c/ftllQtl mwm/lt1m1I tlt'Cll/'l't!IWtW fA00.1~. 1111d POSl11l111etl (/('(;lt/mlN...

Role ofODC for Non*LWRs 7 Tho dmit regulntory snide states: "Tfl,~etlwr, tll(l,1'<' m711/1Y!111(!111.< Unst.'<.l on the "gcnomlly applicnble" statement fmm Appendix A in the remgnl:tt that d/fl/!rent req11l1Y!/llQlll.< may ht* 11em~.wu:v.fiw 11011-/. WR previous 1itm1gmph, requirements" should be Nvised to "adupted des/Mm." rcauirements,

Role ofGDC for Non-LWRs 7 The drat\ r1111ulatmy guide states: "Tho mm-I.WR c/1wlg11 <'l'ilerlu This statement is not adequately clenr and predictable for industry. The davclope1I by llw NRC .1*1<1/ft1111l /11d11ded /11 Ap11u11di<'lt.* A to (' t//'tills stuff appom-s to be saying that tho guidnnce in this dmt\ regulntmy guide r11g11/111m:11 g11ldt*, are l11t**11dc'<I ttJ pmvlde s111kello/d,*1w ll'ilh lnsl,q/lt /1110 mny not be the com11lete list of design requirements thnt apply. However, 1/1<' ,,11r1.rs vl<'\IW 1>11 lww the GDC "111/d he illlt*1p1'Clc1/ tu 11ddross mm* the Inst phmse of the cited text implies that the items being nddressed in Mt'R dtwlg11.fil1m11v.1*: /wwe1't'I\ l/11ts1* mv nut **m1sidered It> />e .fi11<1/ ur the dmft regulatory guide mny be incomplete and nol a fully acceplable hl11dl11g Y\',~11rd/11g w/wt 11111y ewf/11111/(v be req11ired.fiw11" mm-lWR npproach for developing the nssociuted principal design criterin. It is llf'(l//**11111." recommended thnt the phrusc ""hmv<:\'t:I~ the.*w tu'Q 1101 t*m1sldt>red to be

.final or blndl11g regarding what 11111)' ewm/1111/(\' he roq11ilvd.fiv111 a non-Ul'R a1mlit'a111" be deleted.

Role ofODC for Non-LWRs 7 The dmft regulatory guide stntes: "Tltt* NRC rmig11izcs tile hene.flts to Suggest chnnging "benefits" to "fotme benefits" to make it clear that this r/.~k i11fimn/11g tlm 11011 lll'R d<wlg11<*rllcr/a10 Ilic e.we111 p11~wih/c, initinl set lms not been risk-infmmed beyond the general consideration of denendlnM 1111 thc dos/Mn l11/i1r11111t/011 <111d data uwiilahlt'. " risk consistent with the LWR-based GDCs in Anoendix A.

DOl!*NRC' lnitintive Phnse l 8 111e dmft Ng,ulatory guide stntes: "71m AR.DC' aro lntMded to M A better term would be "technology inclusive" to align with the list of six tc/1110/oµy 11~111m/ 111111. tll<'l<fill'f!, m11/d app(v to any ~Y/I<' qf'mm LWR technologies nbove. nnd 10 exclude LWRs. The DOE proposal was based dt~S/~ll," on the six ad1*nnccd reactor l<'Chnologies sununari>.ed in the previous namumnh. and not "anv tvnc".

Key Assumptions 9 Th11dmt\.1'tlgnluto"11111ide stntes: "11 ls the l'<'Sf'llllsib/11~1* oftlm Since ARDCISFR-DC/mllTGR-OC apply to nonnnl. AOOs. nnd design*

upplirnlll to dt'111011stmtc m111pli<1111\* with 11ppll<'<tble severe fKx11de111 basis events, and do not pertnin to BDBE l'tlgulations, this sentence Is 111111IJDBIX1\*g11/uti1111s am/ mx/~111; lle11w11sm11~ why mi1* tlt<1t WY! 11111 outside the scope of this l'tlport.

It Is l't'C\>mmended thttt this kev uss11m11tlon be dQleted.

QOE/Nntlmml L11bm11Wv '[snm Comments tl!l.QUJO BegulQtory Guide DQ* J:pO

• J)ockgt ID NRC-2017-0016: Pugc 3

9 The- dmt\ 1'\lg11lutlll'Y guide states: "W/1/fo dQw/op/11/.! the mm*Ul'R This te.'lt implies that non*LWR designs must designed lbr u coni d~.li/.!1111rllt*rlu. ll#Q s11rtf11ssm1wtl tlto1 a mro dl.mtptlw utx11d~111 will ht* dis1*uptlve accident that is a detenninistic lmldover from the past that t/Qm1111.~1mwd It> he! o .1m'\lt't! o*-cllleill or" 86/JE hy the upp//mnt. " cun'\lnt risk-informed design app1'0t1chcs will likely olimlnnto from considemtion, !'01' some technologies. the tenm "scveni accident" or "clll'\l disntptlvu t1ccidcnt" nni not teclmicully meaningful. A goal ofnon-L WR designs would be to eliminate core disrnptiw accidents from consideration by reducing their likdihood to less thun the lowc1*

tl"\lucncy threshold for beyond design basis events.

II is recommended that this kev ussumntion be deleted.

Kc)' Assumptions 9 1'he dmft l'\l!,llllatmy guide stutes: "S<1/i'I>' dtwlg11uNQ<'liwtsfiw11011- The statement is correct (replace "objectives" with "upprouch") hut it's 1.lf'Rs ,~,,, d/l/b1-.wih.~111111/11/li* lrom 1/u~~e '1.1wtw/111ed wllli l. lt'Rs. " not clear whv it is listed us an "ussumntion",

Key Assumptions Tl\Q dml\ t'e!/.Ulatmy g.uido states: "f'mpo.1't!d GDC 11dt1p1111/011.1* 11-ert* This is the better choice oflanguu1:1e - NRC should use "uduptntion"

.fii~u.w:d 1111 1111~\'Q 1wo1i<'d.Jiu* impml'ed t\'/,!1tl111ory ce1*111/11~t' and throughout.

t*ltll'll\'."

Key Assumptions Cun'\lntly. the folluwing items ure locutcd in the text of the NRC lt seems reasonable to state these in the assumptions to hig,hlight that rationales: the1'\l nre key policy items discussed in tho regulutory guide that Ul'\l still unresolved.

• Prior to issuing this rugulntm'Y guide us final. it nppeurs that Commission ugreement will be nct.'\led on tho "l\mctionnl containment" performance requirements for the mHTOR.

• In addition. stuffm:centauce of the "SARR DI." will also be nee<kd.

Harmoni:rotion with 10 The drat\ l'\l!!Ulutory suidc states: "Tltt* NRC will m111/1111e to m1m//or The last sentence stoles that NRC will conside1* use ofintcnmtionul 1nternational Standmxls 1/1/(l mllahornte 011 tltese d1w1111w111s wul .vmsltlc*1* uslll/.! !Item w 1/te standm~ls. Will the US industry get to review and comment on these exlo/1/ 11rtwtlml /11 d<weloplt1/.! SFR 1/osi/.!ll l'rilcr/11. " international standards-bused criteria'?

Harmonization with 10 "llarmo11/:atlo11 w/1/i /111"111111/01111/ Standard1*" It's not clear why this section is included. and if it's retained. why it International Standards doesn't include other inlcrnational etT011s. such as the IAllA CRP on safotv desiun criteria for mHTGRs.

Hannon ization with 10 Tho drat\ 1'\lgulatory guide states: "Tlw lntcmatlonal A111mlt* fillt'l'l(t' This lust ptm1grnph focuses sc>lcly on the SFR. There is a similar activity lntcrnationul Standards A/,!CIW)' (IAEA). /11 (.'()l/abomtlt111 witll tl11* /11tem111/m111/ 1'1Y!/et*/ ()/I unde1way for modular HTORs that should be cited.

ll111om1l1't! N11de11r Rt*Mtmw 11111/ F1wl CytJl<w aml Iii* Genomlimt IV llllt*1*11111/t111t// Forum, es111l>ll.~li~d 1/w Sod/11m-Omled /il1,1*1 Ro11ctur 11tsk Forc.~.*

1 Intended Use II The dral\ regulutmy suide states: "Fol' <w11111p/Q, Fl/Rs mX' ll1111/d-me111/ FHRs are not liquid-metul reactors. Fil Rs ure ti type ofm\llten-sult*

/'(!(l('llll'.\' /11'111/SC 1r/stnw111ml l.Wll/YlfllC (TRIS()) .fiwl. whit*lt I.~ 1/1e St/I/IQ cooled high-tompemture reactors that use u fixed core rathc1* tha11 liquid fiwl used liw mlfTGR 1ooh110/ou/Qs. " fuel.

Intended Use of this 11 The dmt\ 1'\lguh1tm*y 9uide states: "llppllm111s 1110,v 11su I/tis fl.G to Should lldd something like "ufter considel'ing the underlying Sllfet)' basis Resulutmy Guide dew/op all or (ltll'I (i/'lh<' PDC 111111 m'<<frt*e lo t'lltlMC 111111111/,! 1/w for the criterion und U\*aluHting the rationale for the udllptution described ARDC. SFR-DC. or 111/J1'GR-DC to dcm/on e11d1 PDC. " in this Reu. Guide" to the end ufthis sentence.

QOE/Natiom1! Lnbtwntop* T()llm Comme11ts on DrnQ Regulatory Guido DG-1330 - Docket ID NRC-'.!017-0016: Page 4

11 '1110 draft ivtmlut(lcy guldo stutes: "F/1111/(1\ 1/1e 1Hm-l.Wll </Q,~/g11 Should udd something like "ntkr ccmsidering the unde1*lying snfety lmsis

1'/IQl*/o cm de\'elC>/X!d /ly I/le NRC s111(fm't' /111~1Kkd tu pmvlde for the critel'iu nnd cvuluuting the ratlonule for the udnptution described in

• 1*111ke/m/dQr.I' wltli /11s/g/11,1* 11110 I/It' .*tqif's l'leuw 011 how tilt' GDC m11/d this Reg. Guide" to tho end of this scntcnco*

h£< l11wr111'C'll~l 1<> c11/c/1'1'1<s 11011-l.WR 1kwlg11.Jhu111n,,,,. /11""'""'" lh<'>'<' m-c 1101 rn11sld~wd to l>t*,/11K1I or hlmil11g u11 w/u1t 111<Q' <'Wlll11<1lly ht; i...,,,,.,..,...,....,..,,...,..,..,...,,.--,---1=-.....,.,---1-.:,'~,,,,,..,, II ti lltlll*/.tt'R (I lli<lllll, ,,

Tubl~ 1. Multi lo llml'iers i-;.="-"'-""==....,,==-.+-.....;.,.._ 14 ___,*1"'11"'Q lutorv ullle stutQs: mllTOR-DC 18 * "S1111w as Gf)C" Should su '"Sumo us ARDC" Acron~ms 22 Tho dm ivgulutory guldo stutes: "SAllRl)I. * .111<1<</Jlod 11cc't'pt11h/o Not whut wus proposed: should bo "specified ucceptnblo cm'Q

.~1wro111 mcllomw/lt/e m/co.1\* 1/Q,,l,~11 //111/1" i*tulicmuclide Nleuse design limit", The detuilcd lmsis for this comment ls l'l.Widw with commonls on modulur MTOR-DC IO.

Rctll1vnccs :as *nie druft N!!lllntory guide stutes: .12. "DOil. Tm1/11 S1ifi1. Argt11111<' The NONI' - nmdulur HTGR training mnterial also sh(luld be referenced.

Na1/11nal l.uhom101:1'. "&11//11111-<.*ool?d Feist 1\'1WIOI' (SFR) T<'clmology O\'t'f'\'/(tl\1...

Appcndil<A A*l The draft regulntory guide stutes: "Th<' NRC s111/ftlw11 deh!rm/11cd what The "ifany" pnrt should ho separated from the Nst of tho sentence with

/{<my t1tf(lpWt/011 \l'(IS fl/>/>IYlf>r/<1le.Jiir mm-/,ll'lls." commas: "The NRC stnffthcn dctennined whnt, lfnny, ndnptntion wns n 1ro rinto for non-LWRs,"

Appcndl~ C C-1 lntrnduction Rofo.Nnco is mndo to tho "Glossncy" section of tho guide for n definition of the modulnr HTOR. but no Glossary section is rovidcd in the dmtl.

QPIVNotional Lnborntory 'fom11 Commonls on ()rnO Rcguhitory Gujdg DG-1330 - pocket IP NRC-2017-0016: Pugc 5

DOE/National Laboratory Team Comments on Appendix A - ARDC Docket ID NRC-2017-0016 Note: Criterion ore not Included the toblo If tho team had no related comments on the criterion or rationale language.

C1'ltHlon 2017 -NRC ARDC 'fltlo nnd Content 2017- NRC Rntlonnlcs Teum Comments to R<'<IL'tord~slgn. (No rutlonnlc pro\'idcd) lllc>:lbllity to Apply SARlml.

Snmcns <JDC Some thst rcnctor designs Ulilize vented t\iel concept that rclcnsc the fission gas to the primm')' coolalll during normal operation. SARRDL concept may be more applicable thnn SAFDL for such designs, SARDDL would nlso npply more rendily to liquid fuekd molten snit renctot' concepts. It would be very uscfol if the ARDC-10 mtionnle offered the flexibility to ndopt the mHTGR-DC 10 approach in such cases.

16 Co11taln111w1t d~s/gn, For non-LWR t<'Chnologie~ other tlmn SFRs nnd m*HTORs, Add Fnnctlonnl Contninment Lnni:nni:e SnmonsODC desig.ners mni* usc the current GDC to develop nppllcnble ARDC 16 language should include technology ncutml prlucipnl design criteria. However. it is nlso recognized that containment requirements which can be subsequently chnrnctcristics of the coolnnts, fuels, nnd contninments to be npplied ton specific technology. Tho originnl DOE/INL used in non*L WR designs could shnro C(lllllllon fontures with longungo for ARDC 16. which wns \\Tittcn with the SFRs und mHTGRs. Hence designers may propose using the ol\i*'Ctive of being technology ncutml. is provided below.

Sl'R-DC-16 or mMTOR-DC 16 ns npproprinte. Use of the "Co111a/11111ent tleslg11.

mllTOR-DC 16 will be subject lo n polio~* decision by the 1l re1wtorfi111<'1/01111/ co11tal11111ont consisr/11g ofa Commission. Seo mtionulc for mtffOR-DC' 16 for furthc1*

.~lrm*tm*u ,\*11r1*omu/ing tlu.t ret11.*10,. und its ('oollng infmmntion on the policy decision.

S)WWlll Ill' multiple harrl1*1w intvrnal mullor cslt'l'lllli 111 the rn11<'/or and Its mo//11g S)Wtem. shall he

/Jl'tJV/de,/ to t'ontrol tlw rt'leas1.* ~f'1't1tllouc:lh>lty to thl* cm't'/nmnwnt and to nssm-c that thc.tl111t/1mal c1111talmm'llt dtwlg11 <'om//rlons l1111~>rtant to .wif<*ty am lltJt e.\w1*detl.fi1r as /011g as pMt11/at,*d <1<x*/d,*111 cond///011s1\'lflllre...

The concept ofn fonctional contninmcnt would be of interest tbr upplkution to other technoloiJics. Applying this rocommcnduticm would pl'Ovidc a high-level t*'Chnology-noutml ARDC' which could be used to obtnin Commission npprovul of containmclll pcrfonnancc criteria. SFR nnd ml-ITGR DC' 16 woultl then serve to illustmtc how technology-specific design criteria can be derived from ARDC 16.

QOE/Ngtionol Lnbomltw T1;um Comments on DrnO R9gulntory Qujdo DG-1330 - Docket ID NRC-2017-0016: Pugc 6

C1*1t~l'lo11 . 2017 -NRC ARDC Title 111111 Co11te11t 2017 - NRC R11tlouules Tcum ~;11mme11ts F1111ctlmu1I C1111t1tl11ment Polley Issue Discussions ot'Commission µolk)' decisions oo funclionnl ctmtainment need 10 be worded careful~*. For the modular HTGR. a policy decision is no\ needed t'e!lUrding the !lCncrnl ac'Ceptnbility ofapµlying a funclionnl containment (radionuclide retention) appn1ach that differs from a com*entional LWR high-pressure, low-lcakase strncture. However. basl>d ou thc SRM to SECY-03-0047, a policy decision is needed regarding lhe performance criteria to be applied lo a 1\mctional containment. The infonnation k1ca1ed in the mHTGR*

DC 16 rationnle conectly states that a poller decision regarding 1\mctional contninment po1*formance requirements and criteria will be needed. It's noted that containment pcrfonnance criteria for LWRs are provided in 10 CFR SO Appendix J, mthcrlhim in the GDC of Appendix A. The lust two sentences in the rationale for ARDC 16 should be deleted.

17 E/l!{'l/'k powel' ,\\Wl~ms. A reliable powe1* S)'Stcm is re<tuir.'11 for SSC's during postulated Sec positive comment table.

Electric power systems shall be provided to pe1mit occident conditions. l'owe1* systems shall be sufficient in timctioning ofstructmvs. systems. and components copucity, cupubility, und reliability to ensure vitul sufoty importunt to sall:ty. The safety timction for the systems shall functions nre muintuinl>d. The emphnsis is pluccd on 1vquidng be to provide sufficient cupuclty, cupabilit.,v, nnd 1vliubility rcliubilil)' of power sources mthe1* thun p1-esc1*ibins how such to ensure that (I) specified ucceplnble fuel desig,n limits und 1vliubillt)I can be uttuin.:<I. Refornnce to onsite vs. of!:,ite design conditions of the reuetor coolant tmundnry ure 1101 elect1*ic powtlr systems wus deleted 10 provide for those reactor exceeded us 11 result ofnnticipulcd operational occ.11n'lln1.'lls desig,ns that do not depend \ln ot'fsitc 11ower fol' the t\mctioning and (2) vital l\mctions thtll t'llly un electric powe1* are ofSSCs impm1unl to sufoty.

nmintnined in tho event \lfp<>stulnted accidents.

Text 1vl11ted to ", .. supplies, including bmtcrics. and the onsite The onsito ohictric powe1* systems shall huvc sut11cient distributi<m system," wus deleted tll tlllow increased t1exibility inde1wndenC\l, fl'<lundane.y. mid tcsu1bility to 1wrfunn theil' in the desisn ofoffsitc powc1* systems for advanced 1vnctm*

sttfoty t\mctkms, nssuming u single fllilurc. designs. Mmvc\*cr. it is still expected tlmt such m1sitc systems must remain cupublc ofperfonning us.*lsncd sufoty l\mctiuns during accidents as a C\lndition offl'<Juisile 1vlit1bility.

111e e~isting single switchyard nllownnce 1vmnins nvailable undc1' ARDC' 17. lfn partlculm* udvnnccd design requires the use ofODC single switchyard allowance wording. the c.lesignor should look lo C1DC 17 for guiduuce when dc\*cloping l'DC.

lfek>e\l'icul powo1* is nol rcquir.'ll to pcnnit f1111ctioning of SSCs i111pmtt111\ to snfcty, the requimncnts in lhc ARDC mv nu1 applicnblc lo the design. In this case, the fonctionulity of DOE/Nntional Lnborntorv Toam Comments on Drnft Regulatorv Guide DG-1330 - Docket ID NRc..:20I7-*0016: Page 7

Criterion 2017 - NRC AROC Title nnd Content 2017 - NRC l~ntlonnles Tcum Comments SSCs importmit to snfety must be fully O\*alunted ond documented in tlw design bases.

"R~'lletor coolant pressure boundary" has been relabeled as "renctOI' cuolnnt boundmy" to create a more bruadly applicnble non-LWR term that deti1ws tho bmmdocy without giving miy implicntim1 ofs)'Slom opemting pressure. As such, the term "reoctm* coolunt bmmdm)'" is nppllcnblc lo non-l.WRs thut oporuto ot either low m* high pressure.

26 Ro111'1M{V control SJWl~/llS, Recent licensing uctivity associated with the application of lm1101*tnnt to Safety Reactivity control systems shnll include the following ODC l6 and ODC 27 to new renctm* designs "Response to Tho term "important to safety" is almost universally oopubilities: Oop Analysis Summary Report fm* Rcuctor System Issues." understood to mean sufety-n:luted in the context of the (Rel'. 26) and Response to NuScale Gap Analysis Summury ODC and ARD(\ ARDC 1-5, referenced in the phrose (l) A means of shutting down the reactor shull be provid*'11st (v.g., me~I ARDC 1-5)"

to ens111'<l that. under conditions ofnormnl opcmtion. Genet11l Design Critcria 26," (Ref. 27), l'<l\'enll'\I thnt odditicmnl most often refer to "snfot)' fonclions," strongly implying including nnticipated operntioual \lccun-cnces, and with clal'it)' could be 1nuvided in the mvn ofreoctivity control snfotj* systems. The DOE/INL ARDC report (December appropriate margin for mulfunctions, design limits for requirements. ARDC 26 comhines the scope ofGDC 26 nnd 2014) dclined ,;importont to snfcty" os follows:

fission product bnrriera om not exceeded. GDC ~7. The development ol'ARllC 26 is infonncd by the "8a.1*t*d on exlsli11g 10 C"1t Sii Ap1x*11tl1'.t A /c111g11ag,,,

pl'Oposed Genemi Design C'1*iteriu of 1965, AllC-R 2149 ond till.~ <l<wiglltlll<lll n1fi!1w lo s//'ll<'lllr<'S, S)Wl<*ms, mu/

(2) A meuns of shutting down the l'tmctor mid nmintt1ining N1wcmbcr S, 1967 (32 FR l0216)(Ref. 28): the current ODC

~*imptmel//s (SSCs) t/1111 pmvld<* 1Y:aso1111hlt*

n sufo shutd!lwn umler dosign-bosis ovent conditions, 26 ond 27: the dctinition ofsnfcty-rolnlod SSC In 10 CFR S0.2:

ass11ranc:e tht* jiwilll)' <'<Ill hQ opemtvd witllo1111111d11e with approprintc margin for malfunctions, shull be and SHCY-94-084, "Policy and Tcchnicnl lssucs Associuted risk Ill tlw Ilea/th a11d .wif<*ty 1>.fth~ puhli<'. SSCs wit/1 provided. A second menns of reactivity contml slmll be with thc Rcsulntoty Treatment ofNon-Sntbty S)'stems in this desig11111/011 al\' sq/ill)' n*laled and al\' relied provided thnt is lnde1wndent, diYcrse. nnd copoblc of Pnsslvc Plnnt Designs" (Ref. 29): ond tho prior npplicutit'n of 11pa11 to rnmai11.fi11wlio11a/ during <kwign hasi,,

nchieving nnd maintaining safe shutdown unde1* renetlvity control rnquh-cments.

cm:ltlel//,,,

design-basis event conditions.

Current C1DC 26, tirst sentence, stoles that two reactivity Uml11e 1*/sk is 11ssot*/a1ecl 11'//// 1/ic l1111hili()' lo msuro (3) A system tbr holding tho rtmctot* subcrltlcnl unde1* cold contl'Ol S)'stm1s ot'difl1mmt design 1winciples shall be Ille mptrhilily to prewlll or mill[!ate Ille conditions shull be pro\'ided. provided. In odditiun. tho NRC has not licensed u powo1* <'OllS<'t/llQll(XW <>fawi<k*nts wll/d1 rn11/d res11/1 in rnnctt11* that did not provide two indopmdont mcons of' shutting olJ,"tc nulio/ogirnl ovmscq11c11c<W e.w:eed/11g tlw down the reactor. limits set,{imll 111 Ill C/i'fl. SIU./ (fl/' Iii Cl"R 52.79)."

(I) Cmwnt GDC 26, second sentence. stoles thnt one of the Within the scope and context of the GDC, "importnnt to 1-cactivity control systems shall use control rods mid shnll be sofoty" is cquivalcm to safoty 1-clatcd. Therefore. it is cupoblc ofrnlinbly controlling 1-coctivity changes to ensure recommcudcd that the subject pamgmph in the mlionalc thot, under conditions tlfnonnol opcrntion, including AOOs, be reworded to avoid potcntiul contrndiction with the ond with appropriote mal'!!in for malJ\mctions such os stuck common usage of tho tenn throughout the GDC and rods, specified acceptuble fuel design limits ore not exceeded. ARDC.

The stnff1vcosni~es tluu specifying ctmtrol rods mny not be suitoble for ndvnnced reactors. Additionally, reliat>ly ARDC Scope Changes controlling renctivity, as required by GDC 26. hos b<.'<ln Item (l) seems to hnve n uarrower focus than the GDC, focusing more on shutdown capability than on reoctivily DOE/Nutjonal L!!bomtory Tgnm Comments on DmO Regulatory Oujde DG-1330 - Docket ID NRC-2017-0016: Puge 8

C1*itc1*ion 2017 - NRC ARDC Title anti Content 2017- NRC Ratlonnlcs Tenm Comments intorpreted as ensuring the control mds are capablo ofmpidiy control and does not appear lo retlecl the requirement of (i.e.. within a lbw seconds) shutting down the reactor (Ref. 27). ClDC' 26 to have two reactivity contml S)*stems for contmliing reactivity for nom1al opcmtions and AOOs.

l, The staff changed ~'.t1n1ml rods lo "meuns" in'recognltkm thnt In addition, Item (1) of this comhined design cl'iteria advanced MICl<ll' designs nmy not rely on commi rods to requires two independent nnd diverse means of mpidly shut down the rencto1* (e.g.. ulternntivc system designs nchieving and maintaining safe shutdown under design-or inherent feedback mechanisms mny be relied upon to basis conditions whereas GDC 27 seems 10 nllow a pei*form this t\mction). Additionally, specified accopltlblc fuel collective nnd combined capubiiily.

Msign limits" is t'llpiuced with '\lcsisn ilmits for fission pl'Oduct bllrriors" lo be consistent with the. AOO acceptance The existing mlionale docs not e.~pilciliy explnin the cl'iteria. ARL1C 10 and ARDC 15 pl'Ovidc the appmprinte apparent scope changes thnt occurred in the tmnsillon fi~,m the ol'iginai ClDC language to tho cun'<>nl ARDC 26 design limits for the t\tel and renclor coolnnt boundary, respectively. A non-l.WR may not necessm*iiy shut down language. The rationale should be re"ised 10 include nn c~plnnathm for the llppm'ilnt scope changes. In addition.

rapidly (within seconds) but tho iohutdown should occur in a time frmuc such that the fission product bnrrier design limits a chanse in the title, such ns ReactM{t' Co11tml Sy8tem m'l1 not exceeded. In regards to snfot~* dnss, the cllpability to S/111td11w11 Cc1pability, Wllllid bct1e1* align the ARDC nnd shut down tho rcllCIOl' is identified ns u function pcrftmued by lts title.

sufet)'*rolntt.'\I SSCs in the l 0 Cl'R S0.2 detinilion ofsatbty*

related SSCs. ARDC 26 Item (I) also incl11dt.'\l 1he replacement of'

'\'IJWC/f/ed tK'tNptahl~./iwl d~sl!ln limit"" with "design (2) C11rm1t ODC 21 Sillies that the 1vuctivity control systems llmlt.~.fi)l'}/sslun p1vid11ot lmrrlmw." The discussion in the shull be designed to haw a rnmbined cupability of reliably rationale and the NRC staff presentation of February 22.

contl'Ollins rouctivil)' chanscs to ass111v thut. undei* posmiated 2017. indicnto that tho focus of\his chunge is on both the accident conditions nnd with appropriate mat'!!in for stuck l'\lds. fuol and the rencto1* coolant houndmy. Addition of the the cupabllity to cool the cot'Q is maintained. Reliably t'ilnctor coolant boundary is un increase in scope fmm con1mllins reuc1ivity. us ""'<luircd by ODC 27. requires 1ha1 the ODC 26 relative lo whut needs lo be protected from 1*1mctor achieve and muintain safe. stable conditions. including failure during nonnnl operation and AOOs. This change subcritleuiity, using only safoty related equipnwnt with margin is inconsistent with the foot thut some AOOs could for stuck rods (Ref. 26). The tirst sentenl:<.' of ARDC 26 (2) itwolvc fililllre of fission product barriers (e.g... failure of l'llfors to tho snfoty*t'lllnted means (S)*stcms and/or mcciumiw1s) instmmentntion lines. sample lines~ etc.), Furthennore~

to achieve und maintain sutb shutdown. "Mnintuin snfo shutdown" indicates subcl'iticaiity in the ions tenn or an nothing is provided in tho rationale 10 pre~ent future cquHibrium condition natumlly nchicvcd by the design. interpretations of the lnnguagc us nlso encompassing the The stnffchnnged "renctivity contl'Oi systoms" 10 "menns" in reactor containment for those designs thal use a t'ilcognition thnt advanced t'ilactor designs ma)' t'lliy on n tmdhional appmach 10 containment. All of these points system. inherent fecdlmck mechanism. or some comhination need clnrificntion.

thm.'Oflo shut down the ivoctor and mnintuin n safo shutdown under design-basis event comlitions. SECY-94-084, "Policy ARl>C l>cvclo1nncnt References and Tcclmicul lssue.' Associnted with the Resuiutory The first paragraph of the rolionnlc notes that the Trentment ofNon-Safoty Systems in Passive Pinnt Designs" development of ARDC 26 was informed by a number of (Ref'. 29), describes tho chamctcrlstics ofa safo shutdown refe1vnces. Most of these references preceded the cun'ilnl condition us l'cactor subcriticlllity. decay heat t'ilmovul, und version of the GDC. An explanation of how these older

!)()E/Nqtiona! Laborntpry Tgam Comments on DrnO Regulutory Guide DG-1330 - Docket lD NRC-2017-00 I6: Page 9

Crlte1*lon 2017- NRC ARDC Title 11ml Content 2017- NRC R11tion11los To11m Comments*

mdloactive matel'inis containment. The sta1Trepla\."Cd refownces supported the chang.es from the cun"Cnt GDC "postuluted accident conditions" with "Mslg.n-basis ovent would be holpfol.

C\lndilions," to emphasize that plunts aw required to maintain a snfu shutdown following AOOs as well as postulated Uso of"Doslgn-Basls t;vent" Language accidents. It is not clear why the wording "desi~n-bas/s ovem

<*m11litio11s" is used explicitly in item (2) whereas The se<;ond sentence of ARDC 26(2\ wfors tu a means of "pa.1*tulatetl <1c<:ide111.~" is used consistently for the rest achieviug. aml maintaining shutdown that is imp011ant to safety of the ARDC/SFR-DC/mHTOR-DC sets.

but not necessarily snfoty related. Tim se<;ond mcnns of renclivity control servos ns a backup to the snfoty-relnted Common C1111se Faihu-cs menus und. ns such, mnrgins for mnlt\mctions nre not requh't.'{l Suggest dmnging the Rntiona!Q discussion regnrding but lhQ se<;ond means shnll be highly reliublc nnd robust (e.g.* "diverse" from " ... dl{Ji:rem 1kw/~111h1111 tht* s<tli'I)'*

meet ARDC l -S). "lnde11endent" indicntcs no shnn.'<l systems t'!Jl<l/~tl m&ms .. to "cl!fli:1vn1 dos/g1111ut stti//eat to or compuncnts with the snfoty-rclnted meuns and "divorso" l'tltn/111111 VIII/SQ fallttr.w . ..

indicates n dltlbm11 design tlmn the snfety-rolnted means. The purpose ofun Independent and divc1'Se menns of contmiling n11nnltlon of Cold Shutdown renctlvity is to preclude n potentinl ll\1mmon cuuse tllilurc Item (2) spe<;itks ".w1fo ,,/111tdow11" whereas item :J a1Tucting both nwnns ofrenctlvit)I contml, which would lead to spcdfies "l\'<1<'11>1' h?/11g ;11h<*riti<wl 11111/Qr ml</

the innhllity to sh\11 down the l'CUctm'. The se<;ond means of mndllim1s. " Safe shutdown stole ls defined in the reactivity llontrol does not havQ Ill demonstrnte thut design rationnle but a dennition of"cold shutdown .. is also limits for fission product bnrrie1'S ure met. needed (confoslon might m*isc flw some. systems if the coolnnt ls th.1zen at 1"1.1om tcmpornture). Suggest Additionall~, the cmrent ODC 26. third sentence. stntes thnt including n sentence in the rationale thut "cold i

• I the second renctivity control system shull be capnblo of conditions" imply temperatures at which rcfocllng.

wliuhly controlling the rnte ot'clumgcs Nsulting from planned, inspections, nud repair fonctions can be porfonncd.

nonnnl power chnnges (including xenon burnout) to assul'll ucccptnble fuel dcsisn limits nre not exceeded. Staff has Achieving Cold Shutdown identified this us an opemtional roquiremont thut is not It is not cleur if item (3) llalls for n third nocossnry to onsu1'0 renctor satbty fll'O\'ided n design complies system/mechanism to render the reactor subcritlcnl. A with ARDC 26( 1). Thewfore. this sentence is not Maim.'\! in paragraph should be added in tho rationale to clarify that ARDC 26. the safcty-rclmed shutdown system is exp<~tcd to achieve snfe shutdown: but "cold shutdown" can be achieved by either a safoty or non-safety shutdown system.

Basis for Opemtionul Rcqniremcnt The 1"0fercnce should he provi<k'<l where the staff identified the rcquh*emcnt that the third sentence ofODC 26 is considered to he an operational requirement and not rclevnnt as a DC.

DOE/Nntjongl Lghorutmy Team Commgnts on Drnn Regulqtory Guide DG-1330 - Docket ID NRC-2017-0016: Page lO

C1*ltcl'lon 2017 - NRC ARDC Title nnd Content 2017-NRC Rntlonnlcs 1'cnm Comments 31 Fml'lllN prvwnli<lll *!llX'<WIOI' rna/11111 ho11mlm'" "Reactor ooolunt pressure boundnry" has been rolubeled as Concern ReR11l'tli1111 "Coolant Chemlsh-y" The rcnctor coolant bound11ry sh11ll be designed with rcnctm* coulunt boundury" to create a more broadly applicable Item (2) adds " ... am/ ooala111 vlwmlstry" to mntel'ial sufllcient murgin to ensure that when stressed undl>r non-L WR term that defines the boundmy without giving any prope.rt)' considerations. This creates 11 degree of opcrnting. mnintennnce. tcstiug. and postulated accident implication ot's)*stcm opernting pressure. As such, the term uncertaint)'. Thcjustification identities "unique conditions, (I) the boundal')' behaves in a nonbrittle manner "t'tlnctor coola11t boundary" Is applkublc 10 non-L WRs that fl(JWntlal t*tmlants" as a concern but "chemist!')'" intbrs n and (2) the pmbnbillt)' ofm11idly propagati11g fi11chu'tl is operate nt either low or high pressm'tl. rcuctive property. Does this i11clude secondary/tertinry minimized. *nw design slrnll 1*cflect scrvlcQ tempcrntm'tls, 1'tlacti1m product internctions decedent from some lnitinl sc1*viec degmdation ofnmterinl 11rope1tics, creep. futi!Jue. Specific examples m'tl ndded to the ARDC to account for the "COlllant chemistry"? At'tl coolnnt contnmi11ants stt'\lss ruptut'tl, nnd othe1* conditions of the boundm;* material hish dcsil!n and opcrn1i11g tcmpernturcs und uniqmi potential considered in the criterion? "Coolant chemistry" could uuder opcmtin11. mnintennnce, tcstiny.. nnd postulllted coolants. be interpl'tlted as n scope ex11ansion and is unncccssnl')'

accident conditions nnd the um,'tlrtain1ies in dctennining given ARDC-14 requirements.

(I) material pl'llpe11ies. (2) the offoots ofirrudiution and cuolunt chcmlsh)' on mntcriul pl'llpe11ies. (l) rcsld11ul. Missing Wol'tls stendy-stute, and transient st1'11sses. und (4) sl~.e ol' flaws. l'l'llpl1sed ARDC lm1s1mgc st.-ems ll' nccidentally drop the hi1:1hligh1ed words in item (2): "Tll~ </Qs/iin .<lwll 1~flt'f..-.t s.mnitl~a1Um1 11fs.en'if.'<.~ 1em1x~1'(tfttres, .w. rvkc 1

(/Qgmdallon 11(matQr/a/ f>TO/Jel'li<w ... "These w*mls propcl'ly uppem* in SFR-DC 31 und ClDC 31.

32 /11spt'('//m11tf1wwtm* t~;o/11111 hmmtft11)'. "Reactor coolant prcssm'\l bu11ndury" has bce111'tllt1beled as Addition of the Wot'll "Functlonnl" Components thot urc pm1 of the t'tluctor coolm1t b01mdt1ry reactm* coulunt boundm')"' to Cfl.'<tte a more broadl)' upplicnble 1'01* the replacement of "rns1/11ii" w/111 "jim<'tional shall be Msigncd to pennlt (I) 1wriudic inspection und non-l. WR t11rm thut defines the bo11ndmy without givins uny 11.wtl11g"; infonnntion sho11ld Ile ttddcd to the rationule to 1\mctionul tllsting of important al'tlus und tbutures to m;,~ess implicution ol's)'stom opmtting pressure. As such. the term explain the intent behind the ntlditicm of the word their structural and leaktisht intesi*lty, and (2) an appropriate "Nnctor coolant buundmy" is t111pticable to non-LWRs tht11 "functional. The word is not included in GDC 33. What material surveillance progmm for the rcuct9r vessel. opemte at either low or high prcss111'\l. kind offunctimrnl testing is intended? What is the mtionale for the addition of this word'?

The staff modified the LWR GDC by replacing the term "t'tluctor prcssllt'\l vessel" with "reactor vessel." which the staff believes is u more gcncrict1lly npplieuble tcm1.

JS l!nwrgenoy em't"' t'fmlin!J,. In most advanced rcactu1* designs, ll single system (i.e., the Reference to Fuel Dnmni:c A system to pl'llvidc sullicient cmcrgenc)' COl'tl cooling shall t'tlsidunl heat rcmovul system) is provided to perform both the Regm~ling the addition of the words "muljiicl damage is be proYi\led. The system safoty function slu1ll be to transfer residuul heat t'tlmovnl and emergency cm'tl cooling functions. //mlted" to the first pnrngrnph of the criterion, the hcnl fl'llm the rcncto1* cm'tl such that effective cot'tl cooling is In this case. the single system would be designt.'<.1 to meet the rationale doos not provide. guidance for how these new mnintnined und fuel dnmnse is limited. requirements of ARDC 34 und ARDC 35 (for more discussion words (which reflect an expansion in scope relative to see NUREG-0968 (Ref. 5) and NUREG-1368 (Ref. 4)). GDC 35) should he interp1'tlted or why the)' have been Suitable rcdunduncy in components und foutut'tlS and However. tho staffucknowlcdges that this may not be the case added.

suitable interconnections, leuk detection. isolution, und for every advanced reuctor design. The1'\lforc, to allow current The added words arc mnbiguous when considering (I) to containment capnbilities shull be provided to ensure that the and future non-I.WR designers the tkxibility to pl'Ovido 11.

what level should fuel damage be limited? (2) What m'tl system sufotv function can be accomplished. assuming a single system or multiple systems to pe1*fonn rcsidual heut the uppl'Opriate measures oftitel damnge? (3) How single fuilnr:;, t'tlmlwnl nnd emergenc)' core cooling, the staff decided to keep would fuel damage be interpt'tlled for n molten suit the ARDC 34 and ARDC 35 separnte in lieu of combining rcuotor or for tt modulur HTGR?

them into n sinsle criterion. Effoctive COl'tl cooling ma)' includo QOE/Notionol Lahormoiy'foam Corn1mm.ts on Qrnft Rogulotory Gujdg DG-1330 - Dockqt ID NRC-*2017-0016: Pt1ge 11

Cl'ltc1*lon 2017-NRC ARDC Title aml Content 2017-NRC Rationnlcs Team Comments maintaining the primnlj' C\lohmt botmdm)' in a conditim1 It nppcara that tho cited ARDC 3S text expands the scope nci<'tlSSUI)' for ndequnte postulatQll accidel\I hcnl removal. Tho of the e1ds1ing ODC\ nnd is therefore outside of the stall's approach to provklc two sepumte criteria is consistent scope of this ARDC effm1, Absent fm1he1* information with the appmnch takm in the LWR GDCs, rcgarding thll intent of these wmds, it is t'CCommcnded that they be deleted from the criterion, This change rcmoves the light*water reactor emphasis on lo!<.~

of coolant nccllknts thnt ma;* not appl)I to every design. Loss ARDC Mlsslnt1 Wot'tls ot'coolam accidems may slill l'l.'quire analysis in ctlt\iunclkm l'mposed ARDC l1mgungo seems tu nccidontnlly dmp with postulated nccidents If they are relevunt to the design. th<> following highlighted words: The system sufety ftmction shall bQ to tronsfor heal ftxm1 the reactor core 111 The tlDC rcfereni.'11 tu eleell'ic ptlWor wus removed. Refor lo l!.J:ll1!l such tlmt t>ffcctiv<> coro cooling ls nu1intuined.

ARDC l 7 concerning those systems thnt 1'\.'qUire olcctric powet\

37 re.w/1111111'1'l'"ldm1/ ht'ut ro111ow1/ .x1\\"M11. ln mo.~1 udvanced rcncltJI' designs, u single s~*stem (i,e., tho Use of tlte Word "l.caktight" A system that provides emergency rn1'Q cooling shull be. Nsidmil heut t'Qmovol system) is provided to pc1*tbrm both the "Leaktight" stand11rds may' not be ncce&~m')' fo1* certain designed to permit appmpriute pe1*iodic t\mctionnl testing to residual bout removal und emergency corc cooling t\mctions, ndvanccd renctor SSCs, but keeping this word in the ensure (I) the sll\lcturol mid lcnktlsht Integrity ul'lts ht this ense, the single system would be desisncd to meet the criteritln inters expcc111tion oflonktlght cupnbility, components, (2) the operability nnd pcrfommnce of the requiremmts of ARDC 34 and ARDC 35, (for moro discussion Determination of the dcgroo to which u system is system rnmponents, nnd \3) the operobllll.v ot'the system us see NlJRECJ-0968 (Ref, 5) and NlJREG-1368 \Rel'. 4)) "leaktight" should be su~i*-ct to acccptnnce criterin that n whole and, under conditions as close to design us practical, Huwewr, the stnffacknowledges that this may not bo the case atv 11pproprintc for each ronctor technology, The words the perfomumce of the foll uperutional sequence. that brings fot' evct')' advn11cQll 1vnctor desi!:].n, Therefore, to allow cumnl "@d l<'uk1lg/ll" shou Id be deleted, the system into operution, including operotllln ofnny mid future non*L WR designers the 11exibility to pmvlde n ussociuted systems and iutertllces neeessnlj' to transfor single system or multiple systems to pe1'fo11n residual heat Title Chan11e decay hent 10 the ulthmlle heut sink, l'Omo\*nl tmd emergency core couling, the stuff decided to keep Tille should rend "Ttl"ti11g ofi<"'ltlwil li<al 1*.wmml the ARDC 34 nnd ARDC 35 sep1m1te in lien of combining emergene>' core <'11111/ng ;Jwlem,"

them into n single criterion, Tho stnff's nppronch tu pm,*idc lwu scpamte criteria is consistent with the nppronch tnken in Connection Hetwccn Defense in Dc11th and System the LWR GDC's, l.cnknge Additional clnrificaiion is needed in the rntionnle to The ARDC hns slightly dilTcNnt wordin11 th11n the GDC Ill explain the criterion that a non-lenklight system mny be cl11rify the sc\lpc of the crite1*ion. Any system, or portions ofn acceptable if "dc:/&11se 111 depth Is 1101 im/xWl<'d by .IJW/em system, croditcd with nn cmcrscncy core cooling function lcakuge," This clnrificntion applies to other criteria (c,g.,

durin11 pustulnted accidents (fot' QXnmplc, a system thnl ARDC 40, 43, nnd 46) that address defense in depth, performs both tho rcsidunl hcnt removal ll.mction nnd the cmcrsency core cooling l\mction) would need to meet ARDC 37, Specific mention of')11"Cssmv" testing hus been removed yet remains u putentiul requimuent should it be nccessmy us a component of" .. ,nppmpriatc periodic ftmc1ionul tcs1ing,,, of coolinti systems,

[)OE/Nmjonnl Lqborntrny Team Cpmmonts on prnn Regulptory Gujde PG-1330 *Docket IP NRC-2017-0016: Page 12

C1*lte1*lo11 2017-NRC AIU>C Title untl Content 2017-NRC Rntlonales Te11m Comments A non*k'llkli!!lll S)'Stem mny bu ncceptnble for smne dosi!!ns prtwidQ<l thnt (l) tho system leak11!!0 dMs not impnct sntbty ftmctions umlet' nil conditions, mtd (2) dofonso in depth is not impuctoo by s)*stcm lonkngc.

"Acliw" lms been deletQ<I in item (2) 11s 11ppmprin1e opembllit)'

11ml perform1mce S)*stem component testing 11ro t'l."lt1ir<id, ret111rdless ofnn nctiw or pnssi\le nnttn'Q.

Refot'Qnce to the opcmtion ofnpplicnblo ponluns ofthu pt'Ok'iltlon S)'Stom. cooling water s)*stem. nnd lll\Wor tnmsfors Is considel\'d pm1 ot'the mot\' geneml "nssocintcd systems,"

'l'o!!elher with tlrn ultimnto hent sink, tho)' 11re pun of the opcmbllity testing \>fthe system 11s 11 whole.

The GD(' refot'Qnce to electric power wns removed. Rcfor to ARDC 17 conceming those S)'stems th111 t'Qquire eleelt'ic power.

40 T<*st/11~ 1i/'mnt11/11mvnt ll<'at 1w1111*11/ .1)wlr111. Specific mention of"pressul\'" testing hns been removoo yet Use of the Word "Lcnktlght" The cont11inmcn1 hcnt l\'mo,*nl S)'Stcm sh11ll be dcsi!Jncd to remnins 11 potcnti11l requirement should it be neccssm)' as a L~nktig.ht" stnndards mny m'lt be llt."Cessury for ccrtnin pcnnit 11ppmpri111c periodic function11l testing to cnsm'Q component of" ... npproprintc periodic function11l testing..," of 11dvunccd renctor SSCs but keeping it in tho criterion

( l) tho stmctuml 11nd lcnkli1,1ht inte!Jrily of its components, containment hcnt remo\'al. infers expcct111ion oflcnktight cnp11bility. Lcaktight (2) the opembility nnd pcrfommncc of the system should be httcrprotoo 11s n structuml integrity element components, and (3) the opcrnhility of the system 11s 11 A non-lcnktight system mny be 11cceptublc for some designs nnd subject to functional testing in that capacity, whole, nnd under conditions 11s close to the design ns provided thnt (I) the system lettkll!!O docs not impact s11fety Dctot*mitmtion of the degree to which a systcnris prncticnl. the perfornumco of the full opcrntionnl sc11ucnce functions under nil conditions, nnd (2) defonso in depth is not "lenktight" should be subject to ncccptnnco critcri11 thnt thnt brings the system into openttion. inchtdin1,1 the impneted by system lenkuge. m'Q 11ppmprin1e for e11ch reactor tl'ilhnology. The words opcrntion of11ssocimcd systems. Rcforcnco to the opemtion of11pplicuble pol'lions oflhe "11111/ /,*aktli:hl" should be deleted protection system, stntctuml nnd equipment cooliu!.!

• nud power tmnsfcrs is considert.-d pan of the moro geneml "11ssocintcd systems" for opembility testing of the system as a whole.

The GOC l'Qfol'Qnee to ek'iltric power wns t'Qmo\'cd. Refer to ARDC 17 concernins those systems tlmt require electric power.

43 7lo.~1/11,q 11/'m11111/11111c111 u111111.1p//('l'C dlJllllll/l N)WIC/11.1'. "Active" h11s b!lQn deleted in item (l). 11s 11ppt'Opl'inte Use of the Wm*d "l.eaktli:ht" The contnlnmem ntmos11het'Q dcnnup systems shnll he opct'ttbllity mtd perlbrm11ncc testlns of&ystcm rnmponents is l.e11ktighl stnndm\ls m11y not be nccess11ry for certuin desl11-ncd to permit appm11rintc pet*imlic ftmc1ion11l testing to t'llquircd re11m\lless oftm 11cti\'e or pns.~ivc nntu1'Q, ns m'Q cited 11dvuncoo rcnctor SSCs but keeping it in the criterion ensul\' ( l) the stmctuml und lcnktlght hllegrhy of Its e.x11mples of uctiw system components. infors cxpcctntion ofle11ktight cupnbility. Lcaktight cmnponcnts. (2) the opornbillty nnd porfonnmK'Q ot'the should be intetpt'Qtcd 11s 11 stntctuml integrity clement

!)QE/Nmionol Lqhorntmx Tepm Cmuments on !)1110 R11gulmory Gulde DG-1330 *Docket ID NRC-2017-0016: Pl1ge 13

Crltc1*lon 2lll 7 - NRC AROC Title and Content 2017 - NRC Ratlonnks Tuam Comments system components, mul (~)tho opcrnbll\t~* of the systems as Examples ofuclive systtims under item (2l have been deleted, und subject lo fnnctkmul testing in that capacity.

ti whole and, under conditions as dos~ to doslgn tis pructkul. both 10 contbnn 10 similar wo11tln11 in ARDC 37 und 40 nnd Determination ofthc degree ta which a system is the pcrformunco of the lhll oimntionul sequen1:11 tlmt b1*ings oosut'll that passive as well as active system ctJmponents m-e "lcuklight" should be subject lo nccepmnce crltcrin 1ha1 the systems into opomlion, includin!,! lhe oprnllion of consldcnxl. arc appropriate for each reactor leehnology The wonls usi\lcinled systems. "ond lc11All~i11" should be deleted Spec.Ifie mention of"pt'llssure" tcs\in11 ht1s been removed yet remains n poll.lntial rcquhvmenl sllould it be neecssury us a compunent of" ... appropriule pcrl11dic funcllonul 1esting..." of cooling s)*stems. A non-leaklighl system ma)' lw acccptnble for some dcsisns provided that (I) the system leakage does not impact safol)* functions under nil c\lnditions. and (2) defense in depth is not lmpt1ctcd l>y system lcaknge.

Tiw ODC 1vfe1vn1:1110 ekctl'ic power was removed. Refer ltl ARDC 17 concerning those systems 1hut require electric.

pOWCI'.

46 1lwti11.~ <!f'stmc111ml 1111d ()(/1tip111em ('oo//ng .~l\Wms. This renamed ARDC accounts for ndvanccd 1-cnc1or system Use of the Word "Lcaktigbt"

,'lllc s1t*ucltm1l und equipment cooling systems shall be design dltlbrenccs 10 include possible cooling requirements for "Leaktight" slnndards may nt>t be ncccssnry for certain designed to pemiit approprinte periodic ftmclional testing to SSCs important to safety. Specific menlion of"prcssure" advanced renctm SSCs but keeping it in the crltcl'ion ensure (l) tho struclurnl nnd leaklighl integrity ofthoir testing has been removed yet remains a potential 11.'Qttiremcnt infers expectation of lenktight capability. Leaktight components, (2) the opornbility and pcrfonnancc oflhc should it bo necessnry us a component of" ... upproprinte should be interpreted us a slructuml integrity clement system components, and (3) the opcrnbilit)' of tho systems us periodic functional testing..." of cooling systems. A non- and subject 10 functional testing in that capacity.

a whole and, under conditions tis closo tu \ksign as prnclicul. leuklight system may be. acceptuble for some designs provided Determination of the dcg1-ce to which a system is the pcrRmnuncc of the l\tll opcrntionul sequences thul bring that (I) the system leakage does not impncl safoly functions "lcuktight" should he subject 10 oeeeptonce criteria that the systems into opemtion lbr reactor shutdown and under all cC1ndi1ions, and (2) defense in depth is not impoctcd ore oppropriote for each reactor leehnology. The words postultllcd accidents. including lite opemlion ofru;sodated by system leukage. "mu/ leaktlglll" shmtld be deleted systems.

"Active" hos been deleted in item (2) because appropriate opembility and perfonnance tests of system components arc required regardless of their octive or passive nolure. The LOCA reforcuce hus been 1vmo1*ed to 11ro\'ide for uny postulated accident that might affect subject SSCs.

The ODC t'llfercnee lo electric power wos removed. Refor Ill ARDC 17 concerning tlmsQ systems thnt require elcct1*k power.

QQELliotjQD!!I Lqboratrny Tonm Crnmmmts m1 Druft Rogulutory Gujdc. QG-1330 - Docket ID NRC-2017-0016: Page 14

DOE/National Laboratory Team Comments on Appendix B - SFR Design Criteria Docket ID NRC-2017-0016 Noto: Criterion are not Included the table If the team had no related comments on the criterion or rationale limguage.

-..... =~~----------"-"==-:=--==-=-=--~-""""=""~-==--=*""""' ===-===-=-"-==..,...---===*=---===..-=-"-=--~-="-"'"""""'""""~"--=="'?=~=~~=~---~- --~--~------'"*~--~--~-~-----~--~~~"~

C1*ito1*lon 2017 NRC S~'l~*UC Title uml Conlmt 2017 NRC Rutlonnlcs , Tcum Comments' 10 Rt't10*1t11*1kwlg11. (No rntimmlc prol'ided) ~'lexlblllty to Ap11ly SARRDI, Same us GDC Some tltst reuctor designs utilize vented fuel concept that release tho fission gas to the primary coolant during nonnal operation. SARRDL concept muy be mmv applicable thun SAFDL for such designs. It would be convenient to offer in SFR-DC 10 rntionalethc floxibilit)' to adopt mHTGR-DC 10 approach in such cases.

26 Rt'<l<'IMI)' "11/1/llJ/ S)Wl<'lllS. Recent licensing activity associutcd with the application of lm11ortunt to Safety SamousARDC GDC 26 and ODC 27 to new 1vaetor designs "Response to The tcnn "important to safety" is utmost universally Rcnctivity control systems shnll include the following Gap Analysis Summmy Repmt for Reactor System understood to mean safoty-relatcd in the context of the capabilities: Issues," (Ref. 26) and "Response to NuScalc Gap Analysis GDC and ARDC. ARDC 1-5, roforenced in the phrase Summary Repmt for Rcactil'ity Control Systems. " ... highly reliable and rnlm.*I (e.g.. meet A/WC 1-5)"

( l) A menus ofslmttins down the 1vactor slmll be provided to Addtvssin!! Gap 11. General Dcsi!!n Critel'iu 26." (Ref. most often refer to "safety functions." strongly implying ensu1v that. undc1* conditions ufmwmal opernti1m. including 27), 1vwttled that additional clnl'it)' could be provided in safety systems. The DOE/INL ARDC report (Dl'Ccmbe1*

anticipated operntionul occm*1'Cnces. mul with 11p11roprinte the area of reactivity control requhvmcnts. ARDC 26 2014) defined "impm1tmt to safety" as follows:

mnrgin for mallimctions, design limits for fission product combines the scope ofGDC 26 and ODC '.!7. The bmTiers ure not e:o:cectkd. "Bas<'d on exl,,li11g 10 CFR 5() tlppt'lldix ti lt111g11ag",

development ofARDC 26 is inftmned by the proposed Gcncrnl Design Cl'itcria of 1965, AEC-R 2/49 and this deslg1111tlo11 rnfc1w to s/r11c111nw, "'"'"'"'* mu/

(2) A means ofshuttins down tho reuctor and nmint11inin11 a November 5. 1967 (32 FR 10216) (Rel: 2S): the cunvnt Olllllp<lll*llls (SSCs) tht11 pmv/de 1w1.1'0nahle s11fo shutdown under dosign-basis ownt conditions. with ODC :!(\mid 27: the definition ofsnfoty-1vluted SSC in 10 ass11ra1wo tlwjiwility <<ml bo opemted 11'//holll 1111</11<*

npproprinte margin lhr mal llmctions. shall he pmvided. A CflR Stl.2: nnd SECY-94-084. "Policy nnd Teclmicnl risk tt> the het1/th and Stlfi'I)* *!f'llw p11hllt'. SSCs with second means l>freuctivity control slmll be provided that is Issues Assodutcd with the Regulatory Tl'Catmcnt of Non* this de"/gna/1011 ""' sq/i*ty n*/ated t1nd mv l'<'li<ul uptm to rnnmin fim<'lla11al d111'ing 1/esign ha.w~'

independent. dive1'Sc. 1md cupnblc of achievin!! uml Sufoty Systems in Pussive Plant Designs" (Ret: 29): and U<'<'it/Qll/S, muintoining safo shutdown under design-basis event the prim upplication ofrl.'Uctivity cont1'0l 1v..111il'emcnts.

conditim1s, U111l11e risk is tts"odated with the i11t1bi1111* /o c11s11rn Current GDC 26. first sentence. stutes thut two 1vnctivity the l~1p11hlllly to fll'<'l'<'/I/ m* 111//(~alo t/w *

(3) A system for holdiul:\ the 1vuctor subcriticul under cold cmitrol systems of different design principles shull lw <vmseq11e11re.1* ofm:dden/,\' ll'ltich mu/d n*s11/1 /n conditions shull he pro\'idcd. provkh.'tl. In uddition. the NRC has not licensed a power <lf/.~im mtliaillglml co11scq11eiwc,,* e.weccli11,~ the reuc11.w thm did not pro\'idc two independent menus of /Im/ts set,fiirth In Ill CFR 511.3./ (or JU CFR .U 79), "

shuttin!! down the reuctor.

Within the scope and context of the GDC. "important to (1) Current GDC 26, sccmnl sentence. states thut one of the safety" is equh*alent to safot~* related. Thcrefot'C, it is 1'Cactlvity control systems shall use control rods and slmll 1vcommcuded that the subject pDl'Ul:\l'llllh in the rntionalc bo cupuble of1vliably contl'Ollins 1vuctivity changes to be rewmded to a\'oid potential contradiction with the DOE/Naijongl Lnhomtory Tcnm Comments on Dmt\ Regulotorv Guido DG-1330 - Docket ID NRC-2017-0016: Page 15

Criterion 2017 NRC SFR*OC Tltlo nml Content 21117 NRC RntillnalQS Team Co1r1111ents eusum thnt. umk1* C1Jnditions ofmmnnl opemtiou. rommou \ISU!Je *1fthe term throughout the ODC und lncludinl! AQOs. nnd with 11pp1wrlate mnl'!Jin Rw ARIJC.

mnlt\mctions such as stuck rods. specitled ncceptnblc fhel deslyn limits ore not ll.weeded. The stnffrcco11nizes tlmt ARDC Sco11e Chnnges sp*~ifying rontrol rmls mny not tw suitablQ for ndvauced ltm1 (I) seems to hnve n nurrower focus thun the ODC.

re11ct111-s. Additionnll~-. wlinbly contmlling reactivity, as focusins moro on shutdown C11pability than on renctivity re<1ui"<I by ODC 26. has been interpreted as ensuring tho cont1'UI und does not nppenr to reflect the requirement of control rods m-e capuble ofrnpidly (i.e., within 11 lbw GOC 26 to have two rencti\'lty control systems for SC.'tlUds) shutting down the wt1ctm* (Ref. l?). controlling reactivit)' for nomml operations and AOOs.

The stnffchnngcd control t'Qds w *~uonns" in r.-cognition In addition, ltcm (2) of this combined design criteria tlmt advanced reactor designs may not wly on control rods requires two independent and diverse means of to rnpldly shut down the reactor (e.g., altcmatlw system achieving and maintaining safo shutdmvn under design*

designs m* iuhe1-em feedback mechanisms mey be relied basis conditions whereas GOC 27 seems to allow a upon to perfol'm this 1\mction). Additionally. "specified <.'tlllecth'e and combined cnpabillty.

acceptnblc foci design limits" is replaced with design The existing rationale docs not explicitly explain the limits for fission product barriers" to be consistent with the uppm-ent scope changes that occurred in the tmnsition AOO acceptance critel'ia. AROC I0 and ARDC 15 provide from the original GDC language to the c1ment ARDC' 26 the appropriute design limits for the fuel and reactor language. The rationale should be wviml to include un coolant bmmdury, l'esp<.-ctivcly. A non-LWR may not explanntion for the appm-ent scope changes. In addition, necessarily shut down rnpidly (within s<.-conds) but the a change in the title, such as Rell<'lil'i(I' Con/ml S)<'tem shutdown should occur in a time fmme such thnt the S/111tdmm Ct1tmhlllty. would better align the ARDC and fission product bun*ier design limits are not 01tceeded. In its title.

regm'ds to salbty class. the capabilit)' to shut down the 1-enctor is kkntitled as a function performed b)' satcty- ARDC 26 Item (I) also includ<.-tl the wplncomont of related SSCs in the I 0 CFR 50.2 definition ofsnfoty* ".11wcflit'd ai:1:ep11bl<'.Jiwl deslg11 llml1.1*" with "design rolatlid SSCs. llmlts.Ji;r.Jl.1wl"" pmd1w1 bt1rrlers. " *nie discussion in the rntlonnlc and the NRC stalTprescntation ofFebnmry (2) Current GDC 27 states that tho renctivhy '-'tlntrol 22. 2017, indicate thnt the focus of this change is on both systems shall be designed to hnve a combined capability of the fuel and the renctor coolant boundmy. Addition of wliably controlling wt1c.tivlty chm1ges to assure tllllt, under the reactor coolmit boundnry is nn increase in scope from postulall.'11 accident etinditlons and with npproprinlQ mnrgiu GDC 26 relative to whnt needs to be protected from fol' stuck rods, the capability to rool the co1-e is maintained. foilm-e during ntmual operntion nnd /\00s. This change Reliably ct111trollinl! reuctivit~. as "<Juir.'ftl1c lungunse as also encompassing the 1-elated means (systems and/or mechunlsms) to nchicvc and reactor containment for those designs that use n maintain snfo shutdown. "Muintnin snfe shutdown" trnditionnl nppronch to contninment. /\II these points indicates subcdticality in the lon11 term or an <.-t]uilibrium m.-cd clarification.

condition unturnlly nchicvcd by the design.

DOE/Nationul Luborntm*y Team Co1nmonts on Dru ft Regulatorv Guide DG-1330 *Docket ID NRC~-2017-0016: Page 16

Crlterlu!l 2017 NRC Sl*'R*OC Tltlo ltnd Content 2017 NRC Rntlonntes **Team Comments.* "

The statfchanged "reactivity co11t1'UI systems" lo "means" Slife Shutdown, Cold Conditions Termlnololl)'

in l'llCQgnition 1ha1 advunCIXI reuclor desi!!ns moy rolr on n SuBSesled allemntivc to cold coudilions for SFR DC 26.

system. inherent f~lbnck meclmnism. or some Use the deflnilion ofsubcl'ilical under cold conditions combination lhlll'COfto shut down the roaclor and maintain comes from the work on OIF SFR design criteria.

a safo shu1down undc1* design*basis evcnl conditions.

SECY-94-084. "Policy and Technical Issues Associated S11ht*1*/tlrol under rold mmlltlo11s is <feJlm*d as tlie with the Rcgulnloty Treatment ofNon-Safoty Systems in stotv tt'ltli the reactivity *!f'llw reactor kept to a Passive Plant Designs" (Ref. 29), describes the margin hd"w rillro/l~v 11111/cr a proscribed <'UtJ/anl chamcterlslics ofa safe shutdown condition as reactor Mnpcrotw'O ro11ditl<m 111 wl1/t'/1 ln1crnm1lm1s s1wh subcl'ltlcallly. decay heat l'emoval. and mdloactivc <1.*.fiwl 1'0/11udlng. /w1*lodlt* l11.11"Mlon "" "'l'<ll1*

materials conlainmcm. The s1ntfrcplnced "postulated work In tlw roa<'/01* <Ylll bQ C1chlewihlo.

accidclll conditions" with "design-basis event conditions,"

to emphasize that plants nw l'l.'quired lo maintain a safe This is very similar to cold conditilms for l.WRs if the shutdown following AOOs as well as postulated accidents. prescribed 1empCl'lllure condition is< boiling al alnmsphel'ic pressure. This might wol'k for the mHTOR:

The second sentence of ARDC 26(2) refers to a meuns of ifso, ii could be used in ARDC since ii will work for achieving and mainlnining shutdown thnt Is imporlnnt to fluid fueled MSRs as well. It would ovoid the confusion sufely but not necessarily safety related. The second means of "cold" for these high lempcmlure systems.

ofreuclivily control serves as n back.up to the sufo1y-t'Clated menus und. as such, marsins Rw malfunctions m'C ARDC Denlo11ment References not required but the second means shall be highly reliable The first pamgmph of the mtionak notes lhal the and t'Ubust (e.g.. meet ARDC I .s). "lmlepcmknt" dc\*elopmenl of ARDC 26 was informed by a number of indicates no shal'l.'<I systems or comptmcnts with the safely- references. Most ofthese references preceded Che cumnl related means and "diverse" indicates a different design version of the ODC. An explanation of how chese older than the safety-related means. The pul'posc ofnn refct'Cnces supponed the chnnges ti'Um the present GDC, independent and diverse means ofcontl'olling 1'Cac1ivity is and why tho present ODC is considefl.'<l not appropriate, to preclude a potential common cause fllilnre affccling would be helpful.

both mcuns of l'CllClivity cont1'Ul, which wmild lead 10 tho inability 10 shut down the reactor. Tho second means of Use of"Dcsi11n*Basis Event" l.nn1111n11c reactivit)' comrol docs not have to dcmonstmlc that design It is 1101 clear why the wording "dcsign*bnsis e\*cnt" is limilli for tlssion prodnct bll1Tiers ure met. used cspllcitly in llom (2) when the 1cm1 p,1s1ula1cd aceidcnts" is used consistently for the rest oflhc Additionally, Iha cmwnt ODC 26. third scnlcncc, stales ARDC/SFR*DC/mHTOR*DC sets?

that the second 1'Cac1M1y comrol system shall be cnpublc of reliably controlling tho mto of changes resulting ftom Common Cnusc 1aih1rcs planned, normnl pmver clmnges (including xenon burnout} SU!:l!!OSI chnngin!! the Rntionnlo discussion regarding 10 nssure acceptable fuel design limits m*a 1101 e><cceded. "diverse" from " ... d!Jferclll d~sig11 lh<m the .mfi*t.1'-

Staff has idcmitled this ns an opemtional requirement that n:/cltcd llWa11s to t/IJ.fcro11t dt*s/g111101 suf?jecl IO 11 is 1101 necessary 10 ensure reactor safety provided n design "'ommtm cause failures."

complies with ARDC 26( l ). 111erefore. this sentence is not retained in ARDC 26.

!)OE/N!!lionol Lqborntrny Tcnm Comments on Qml\ Regu!atorv Gujdp QG-1330 *Docket ID NRC-2017-0016: Page 17

Criterion 2017 NRC SFR-DC Tlt!c uml Content 2017 NRC Rationales Team Comments Achlcvln11 Cold Shutdown II is not clear if item (3) calls for n third system/mechanism to render the reactor suhcriticnl. A paragraph should be added in the rutlonale to clarify that the safety-related shutdown system is expected to achieve safe shutdown: but "cold shutdown" can be achieved by either a safety 01* non-safety shutdown S)'stem.

Oasis for Opemtlonnl Rcquh'llmcnt The reference should be provided where the staff identified the requirement thnt the third sentence ofGDC 26 is considered to be an operational requirement nnd not role\*nnt as a DC.

32 Jn.1'{K!111/1111 t!ffirlmar.v tw1lu111 bvumlary. "Renctor coolm1t pressure boundmy" hns been relabeh:d os Addition of the Word "Functlonnl" Com11oncnts thut mv pm't of the primmy coolant bound11ry shall "primary roolant boundary" to contlmn to stnndard tenns Replaclm1ent of "IQsl/ng" with fimcllmwl testing":

be dcslgued to penult ( l) periodic inspcetlm1 nnd flmctional used in the LM ~ industl)'. lnformatiou slmuld be add~'tl to tho 111timmlu to oxplain tosting of lmpu11ant mvas 11nd feot11rcs to assoss their stl\lctmal the intent behind tho addition of tho wo1~l "l1mctional."

mid loaktisht integrit)'. und (2) an opp1'0prlato material Tho uso ofthu tomi *~1rlmar)"' Indicates that tho SFR-DC Tho word is not included In GDC 32. What kind of survoillance progmm for thll nmctor vossol. arc applkuble unly to tho primmy cooling system. not the l\mctional testing is intended? What is tho 111tionnlc for intennedlate cooling system. tho addition of this word?

The rovei* sas boundal)' is included as purt of the reactor primm; coolant bo1mdury (refolwd to as RCPB by PRISM) po1* NUREG-1368 (1111go 3-38) (Rot'.4).

The staffmoditllltl the tWR GDC by rcplacinp. the tem1

• ~vactor pressure vessel" with "reacto1* voss.ol," which tho staffbeliews is 11 more gonericnlly applicable tcnn.

3S  !i11e1-gem:y mrn m11//ng. In most ndvm1clltl 1vactor doslgns. n singlo system (i.e .. the l'oxtuol Reforonco to Fuel Dom11ge Same as AR.DC residual hent romovnl system) is provided to pcrfonn both Regarding the addition of the words "andji1ol damage is A system to provide sufficient eme1*p.cnc)' core cooling shnll be tho residual hent remo\*al and emergency core cooling /1111//od" to the first paragraph of the criterion, the provilk'tl. The system snfcty function shnll be to transfer heat functions. In this case, the single system would be rationnlc docs not provide !,!Uidnncc for how these new from the reactor core such that effective COt'il cuoliug is designed to meet the requirements of SFR-DC 34 nml words (which reflect an expansion relative to GDC 35) mnintnined and fuel dmnngc is limited. Sl'R-DC 35. (tbr more discussion see NURE0-0968 (Ref. should be interpreted or wh)' they hnvc been added.

S) and NUREG-1368 (Ref. 4)) However. the stuff Suitable n.'tl1mdanc)' in components nnd features aml suitublc aclmowledp.os tlmt this may not be the case for every The nddod words are ambip.uous when considering (I) to ad1*nncod reactor design. Thoretb1v. to allow current and whnt level should foel damage be limited? (2) What arc interconnections. look detection. isolation. and containment foture non*t WR designers the flexibility to provide a the appropriate measures of fuel damage?

capnbilities shall be provided 10 ensure that the S)'Stem safety function cnn be accomplished. assuming a sinsle tltilure. single system or nmltiplc systems to perfcmn residual bent II is SUB!!ested to replnce the wonts "fuel dnmnge is tvmoval amt emot*gency core coolins. the staff decided to limited" with "fuel nnd clnd damage that could interfere

!)OEIN!!tiongl Lnborato1y Team Comments on Qraft Regula!ory Gujdc DG-1330 - Docket ID NRC-20)7-0016: Page 18

Criterion 20 I7 NRC Sf'R*DC Title nnd Content 2017 NRC Rnllonnlcs Team Comments keep the SFR-DC 34 and S!'R-DC 35 scpumto in lieu of with continued effective CQl'C cC1oling is prevented" nlso combining them Into u sin11le criterion. Effective core consistent with the GDC wording.

cooling mn)' include mnlntnining the primury coolant boundary In a condition ne<'l.'ssnry for ude.iuate postulated ARDC Missing Words accident heat 1'\lmovnl. The staff's npprouch tu provide two Propuscd ARDC lnngunge seems to nccidentnlly drop sepnmte criteria is consistent with the approach tnkcn In the highlighted words: "The system snfcty fonction shnll the LWR GDCs. be to tmnsfor hcnt from the 1'\lnctor core ll1..!U!!!ll. such thnt effective core cooling is maintained.

This chnnse removes the lisht-water renctor emphasis on loss of coolnnt accidents thut nitl)' not npply to every desiyn. Los_~ of coolant accidents mni* still require analysis in conjunction with postuluti.'d accidents ifthci* m'll relevant to the design.

Tho discus.~lon r.:lmcd Ill slldium lenktii;c nnd t'l.'qUired bnrriers wns moved ton new SFR-DC 78.

l'ho one 1'Cfo1'Cnco to electric power was removed. Refer I

to SFR-DC 17 conccmins those systems thnt l'l.'qllh'C electric flllWcr.

36 lmpe<'t/011 <!/'l'1wltl1111/ ht'ill l\*111111~1/ .~11w111. In most ndvnn~'l.'\l 1'Cnctor d.:sisns, n single system (i.e.. the Title Chnngc Snme ns ARDC residual hcnt 1'Cmovnl system) is provllk'd to perform both l'itle "11011ld be "/mp<:ct/0111!f'emefRe11q care <'tw/11111 A system thnt provides emergency cm'C c@llnti shall he designi.'d the residunl hent remoYnl nnd emerscncy Cot'C cooling .~\WfQlll,

to pennit npp1'0Jll'iate periodic Inspection ol'impmtnnt functimis. In this cnsc. the single system would be c11mponents to ensure tllQ intcgrit)* nnd cnpabillty ol'tho system. designed to meet the requirements of SFR*DC 34 and Sl'R*DC 35. (fm*mo1'C discussion sec NURIJG-0968 (Rel'.

S) nnd NURll0-1368 (Ref. 4)) However. the stuff nckm1wkdyes thnt this mo~* not he the cnsc for every ud,*nnccd reactor design. Therefore. to nllow cnn'llnt nnd futu1'C non-L WR designers the flexibility to provide n sinyle system or multiple systems to perfonn residual heat removal nnd emergency core cooling. the stnffdecided to keep the SFR-DC 34 nnd SFR-DC 35 scpnrnte in lieu of combininy them into 11 single criterion. The stuffs uppronch to pnwide two scpnmto criteria is consistent with the nppronch tnkcn In the LWR GDCs.

The SFR-llC hns slightly different wordin!,l than the GDC to clarify the scllpc of the criteria. Any system, 01* portions of a system, Ct'l.'<litcd with nn emef!Jcncy core cooling function during postulated accidents (for cxnmplc, n system thnt performs both the l'CSidunl hcnt l'Cmovnl QOE/Nmjon!l! L11hornt01y Tcnm Comments on Qmt\ Regul!ltorv Guide DG-1330 *Docket ID NRC-*2017-0016: Page 19

Crllerion 2017 NRC Sl*'R*OC Title nnd Content 2017 NRC Rntlonnles .Tenm Comments f\mction nnd the emergency core cooling functkln) would need to meet SFR-DC 36.

The list of exnmplcs h11s been deleted because it applies to LWR dcslsns, und.cach specific design will hnvo different important components nssudatcd with residual heat removal. This l'CYision allows for 11 l\,'l:hnology-ncu1ral Sl'R-DC.

Review of the proposed DOE SFR and HTOR DC fuund that only St'R prtlYid1.'\I spcdnc oxam11los ofimpo1tant components but wct'C gcnc1*1Q In nature 11nd did not lnelude any siQnlllcm1t additional guidm1cc.

37 Ttwll11~ t//'rosld11ul lle11l l't'llltlm/ .~vstem, In most udvunccd t'l.'ltcttlr deslsns. n slnslc system (i.e.. the Title Chnngc SameusARDC residual heat t'Cm\lval system) Is provitkd to 1ierform both Title should be "Te.~tlug 11f'emargent)* mro t*1111/ln11 A system that provides eme1*gcncy COi'\\ cooling shall be dosigned thu residuul hcut removal and emergency cm'C couliu!! ,\y1,\'tem.

to pcnnit appmp1*it1te pe1*iodlc fimctionnl testing to eusm'C (I) the functiuns. In this c11sc, t11c single system would be structuml and leaktlght integrity of its components, (2) the dcsi11m.'\I to meet the requiremeuts ofSl'R-DC 34 mid operability and perRmmmc\l tlfthe system componeuts, and Sl'R*DC 35. (for mm'C.discusslon sec NURE0-0968 (Rel'.

(3) the operability of the system us 11 whole and, under conditions 5) and NURE0* 1368 (Ref. 4)) Howevm\ the sllltT us close to design os practical. the pertbnnunce of the full acknowledges that this mny not be the case for eYery operationol sequence thut bl'ings the system Into opemtion, od,*anC<'<i reactor design. Thewflm::, to nllow *cmwnt llnd including opemtion of any ussociotcd systems und inte1*foces tlltut'C nmt*LWR designel's tho tlexibility to provide a necessary to tmnsfo1* dt.'l:o~* heat to the 11ltlmntQ heut sink. single system or multiple systems to 1ierform residual heat 1'CmlWlll llnd emergency core coll ling. the stuff decided to keep the SFR-DC 34 ond Sl'R-OC 35 sep11ratc in lieu llf

• combining them into a single critcrim1. The staffs approach to provide two separnte criteria is clll1sistcnt with the approuch taken in the LWR GDCs.

The Sl'R-OC has slishlly different wordins than the GDC to clnrify the scope of the critcl'in. Any system. or portions ofn system, credited with un emer;wncy core cooling function dul'ing postulated uccidents (for CKtmiple, a system that performs both the residual heat t'Cmo\*nl function ond the emergency core cooling function) would need to meet Sl'R-DC 37.

Specific mention of"pressmo" testing hus been removed yet remains a potcntiul t'Cquiremem should it be neccssai')'

os a component of","npproprinte periodic fonctillm1l testing..." of cooling. systems.

QOE/Natipn!ll Lnbm'NllJ'Y T!mm Comm\ll)ts on Drl1ft Regul!ltory Gujde QG-1330 *Docket IP NRC-2017-0016: Page 20

Criterion 2017 NRC S*'R-DC Tltlu ond Content ,,,; 2017 NRC Rotlonnles Team Commen~s*

A mm-leaktlght system mt1y he t1eccptoble for some designs provided thot (I) the system lcukoge does not Impact sufety functions under nil conditions. ond (2) defense In depth Is not hn11ncted by system leokage.

"Active" has been deleted In Item (2) as approprinte operability mid pcrfonnoncc SJIStcm component testing ore reqylred. t'llgordliis.~ of on octlvc or possive notm'll.

Relb1'1l11cc t\l the opmlll\ln ofllppllcoblc pm*tl\lns ofthe protection system, cooling wotcr system, and power transfers is considered purl of the more general "assocloted systems." Together with the ultlnmto hcot sink, the)I m'll part of the opcrahllit)* testing ofthe system os o whole.

111c ODC reference to ckct1*ic lll1We1* wos t'llmovoo. Refo1*

to SFR-DC 17 concerning tl111se systems thot require electric power.

41 C11111a/m11~111 <11111ospllm'I' dca1111p. Advonced t'flactors llllbr potcntiol fo1* reaction product Atldltionnl Wording SomcllSARDC gencrntion thnt Is different from thnt associnted with clad First porogmph should end os " ... to ensure thot Systems to control fission products oml other sYbstnnccs that mny metal-wnter interactions. Therefore, the tcm1s "hydrogen" containment Integrity nnd other safety functions are be released into the reactor contoinmcnt slmll be provided os and "oxygen" are removed while "other substonces" is maintained". If the intent is to exempt SFR-DC 41 from necessnry to reduce, consistent with the t\mctioning ofothcr retoincd to allow for exceptions, the requirement for "other sofety functions." the11 "Same ossocioted systems, the concentration and quullty of fission as ARDC" phmse should be removed.

products t'lllcnsed to the environment following postulott'<.I Tho GDC reforenco to electric power w11s removed. Refer nceideuts and to control the concentration of other suhstnnccs in to SFR-DCl 7 conccming thosc systems thnt require the contoinment atmosphere following postulntcd occidcnts t\l electric power.

ensure lhnt containment integ1'11y is mnintnincd.

Unch system slmll hove suitoble redundancy in components nnd footures t1nd suitable inte1'Co1tnl'Ctio11s. lcnk det<'Ction, isolotion.

und eontninmcnt cupobilitles to cnsm'll thot Its snfoty t\mction can bo uccomplisht'<.I. oss11mi1111 n single fitilure.

61 F1iul .*tomgc 11111/ lta1111/111g 1111tl tY1tli0twllv/t)' CTllltml. The 1111dcrlyl11g concept llfostt1blishing functional Missing Woi*dlni:

SumcosARDC t'l.>quiremcnts for radlooctlvlty cllntrol in fuel storage and Following possuge seems occidentally dropped from the The fuel storago ond handling, rudim1ctlvc wostc, ond other fuel handling systems is indcpc11dcnt of the design of11m1- end: " ... conflncmc11t, 11nd filtering systems, (4) with a systems that may contain mdiooctivity sholl be designed tu LWR reactors. Howc\'er. some odvm1ced designs may use Nsld1111I hc11t Nmovul ca11nblllty having 1'1lli11billty ensure ndequotc sofct)' under nonnnl nnd postnluted nccidelll dry fuel stomge thnt Incorporates cooling jackets that con 11nd testability thot t'Cflccts the lmportnnce to snfcty conditions. These systems shull be dc.~illued ( l l with a copubllity be liquid cooh.'ll ot' nlr cooled to remove henl. This of decay hent 11nd othe1* rcshhml hcot removal, and to pem1it uppropriote periodic inspection ond testing of DOE/Nmlono! Ll!bomtmy Teorn Comm9nts on Dmft Regul!!lorv Gujde DG-1330 - Docket ID NRC-2017-0016: Page 21

--~- --- -- -

Criterion 2017 NRC SlR*DC Tiiie llnd Content , 2017 NRC ltnthinnles 1\mm Comments, compmwnts importnnt to sutbty, (2) with suitable shMding fo1* modltloutlon to this GDC allows fm hoth liquid nnd ah* (S) to pi-event slgnllic1rnt t'etluctlon In l\1cl stol'llge radiation pmtoction, (3) with nppmpl'inte contuh1mont, coullng ot'th~ d~* f\iol stofll!le contnine1-s. coollng 11nde1* nccldcnt conditions."

• 1$ Quality 11/'lht* llllcl'mfc/1111<' mo/u111 ho11111lm:v. This critcrkm is similar to GOC 30 in 10 Cl'R Part SO. Remove SFR-DC 75, 76, nml 77 Components that m-e part of the imemiedlnte coolant tiounducy l\ppcndiK I\, and is Intended to cnsmv that. similar to the Sl'R*DC 7S. 76, and 77 arc superfluous who11 evnlunted shall be designed, folirknted. erected. and tested to q1mlit)* rcnctm* c<iolant pressure lmundary, the intemiediate coolant In cumbhmtion with the cited tel\t from SFR-DC 70.

stnndmxls commensurate with the im11tJrtance ufthQ salbty bounda~* Is designed. fab1*knted, nnd tested using quality SFR-DC 75, 76, nnd 77 appear to ho npplicablo when the functions to he perfonued. standards and eontmls sufficient to ensm-e thnt fi1ilurc of role of the intermediate coolant system is commensurate the intenncdinte system would be unllkely. with a satbty f\inction. However. other than the case when it could serve as n path fo1* doony heat removal. the interm<.'<iiat11 coolant system d\leS not have m1y safoty function.

If the intennedime cooling system prmides a safoty*

rolnted heat removal capability. then SFR-DC 34-37 and SFR*DC 78 spcci~v its requirements. The quality and frncturo prevention requirements specified in SFR*DC 75 and 76 arc supplemcntm)I requirements thnt are not consistent with tho requirements for tho decay hem removal and emergency cmv cooling systems specified in Sl'R*DC 34 nnd 35. Likewise, the inspection and testing requirements specified in SFR-DC' 77 for the intem1cdinte cooling system UN contained in Sl'R-DC' 36 and 37. Therefore, for the coso where the intem1edintc cooling system prnvides safety-related heat l'ilmovol capability, Sl'R-DC 75, 76. and 77 Ol'il redundant and unnecessary.

If the intem1cdinte cooling system docs not pmvido safo1y-roln1ed heat removal c.npnbility. then only the requiremems ofSFR-DC 70 nrc necessary to specify the system design with appropriate margin to assure the design conditions of its boundary and the integrity ofthc primary coolant boundnry. Therefore, for the cnse where the intennedintc cooling system does not provide safety*

related heat 1-emovol capability. SFR-DC 75, 76, and 77 are also redundant and unncccssm)I.

76 F1~wt11re prcwmion qf'thc imennedlate mo/ant hm111dm:1*. This criterion is simiim*to ODC 31 in 10 CFR Pmt 50, Se<: SFR*DC 75 commont.

The intemiediate coolant boundary shall be desisned with Appendix A, and is intended to ensm-e thut, similur to the suftkient mm*gin to ensure tlmt. when stl-essed undor operntinQ, 1-enctor coolant 111-essuro boundary, the intenn<Xlinto coolant maintenance. testing, and postulated accident conditions, (I} the buundm'); is desisncd to nvoid brittle and rapidly propagating foctmv modes.

OOE/Natjon11l Laborutmy Tegm CommRDts m1 Druft Regu!ptory Gujdc DG-1330. Docket ID NRC-2017-0016: P:1ge 22

CMterhm 2017 NRC SFR*DC Title und Content 2017 NRC Ratlun11lcs Te11m Comments houudmr bchuws in u 11m1bl'i1tlc munnor mul (2) the probability ofrnpidl)* propu9atin9 fracture is minlmlllXI. Tho s\leond scnte1ml rolnt<'ll to required mmlyses Is removed to muko the cl'ltol'lu more tienc1*io. In this manner.

1he design considorntions mny incl11de. hut m'Q not limited to. th\l-.*c pNvio11sl)' stated in the design critcrio.

77 l11.11><'l'lln11 *!film lnte1wet//(l/c *:oolm11 htmntlw~** 1'his crltel'lon is similar to ODC J2 in 10 CFR l'urt SO. Seo SFR-DC 75 comment.

Components that m'Q pmt of the intenn<'lllnte coohmt bo1111dnry Appendix A. nnd is intended to cnsm'Q that. similar to the shall be dcsi11ned to permit ( \) p<rludic inspcotirn1 nnd llmction11l reuctm* coolmu pNss11N bmmdmr. tho intom1ediat11 roolant testing ofimpurtant m'QUS and fcm11rlls to nR.*css their stmct11rnl bound"ol')' Is dcsit11ml to a\*old briule and rn11idly nnd lcakti11ht intotil'lty commensurntc with the system's proptll!ntinti fhtctuN modes.

lmponmu:c to safuty, and (2) nn npproprintc matcrinl s111'\*eillance A non-lenktight system muy bo nccoptnhle for some pmgrmn tbr the intem1edinte coolm1t bmmdnl')'. Means shall be Msisns provided thnt \ \} 1hc sys1em lcnknse docs not pmvlded tbr detcctlns and. to the extent prnctlcnl. identif)'ins the lmpnct snfct)' fonctions under all conditions. nnd (2}

locution of tho source ofcot>lont lc11kng1i. defense In depth is not lmpncted by system lcuknso.

The stnffndded "commcnsumto with the system's importance to safety." lflc11kngo ofthc intermediate system constitutes n signilknnt risk to 1he plunt. then the upproprinto inspection of the intmucdintc coolant boundary is necessary to ensure thnt the stmcturnl integl'ity of the boundttr)' is mnintnined.

The 1'\.'(jniremeut for tm approprinto surwillanco progmm is

.maintained to ensure lhUI such a pmgrnm is provided. as nlleded. to ensuN that the integrity of tho lutem1tldiate boundary is maintained. At this time. the staffgenerolly docs not expect thnt the projected tlucncc on the intennediatc boundnry will be nt levels that would neccssitnte n mntcrinls survcillm1ce progrmn thnt focuses on tho im11nc1s ofimulintion cmbrinlemcnt. However. the stnffre1.'0gnl1.0s that this mny m>t be tho caso fo1* evel')'

design. In addition. a mntcrinls survoillmtce program muy be 11sed to monitor the ellt'CI of other onvlronmentu\

1.'0nditions mi tho boundnl')* m11tcrh1ls.

QOE/Nntionol Lqborn101y Tunm Cmnmcnts on J)mft Rcgu!ntorv Gujdg DG-1330

• Docket ID NRC-2017-0016: Page 23

DOE/National Laboratory Team Comments on Appendix C - Modular HTGR Design Criteria Docket ID NRC-2017-0016 Note: Criterion ore not Included the table If the teom had no related comments on the criterion or rotlonale limguage.

---

---- - - - - - - - -- ---*- ~-

C1*ltcrlon 2017 NRC mllTGR*DC Title uml Content 2017 NRC Rutlonnlcs Tcnm Comments 10 Rcm:l1)r tllw(Qll, *1110 concept ofspccincd 11ccoplnl>le !\tel dcsi[ln limhs, which SARRDI. Definition The 1-cuctor system nnd ussod11tc>tl hcnt renmvul. contml, und pre\*cnt ndditimrnl fitel follu\'es during tmticlpt1tcd 01wrutimml The NRC stnff's incorporu1ion of the SARRDL us 11 11mtcctiol\ systems shull be dcsigllt>tl with uppro~>riutc nuu'gin occurrences (AOOsl. hns been re1>lnccd with tlmt oflhc \'cplnccmcnt for the St\FDL is 11 \*cry importnm step to Cl\SUl'C 1ht1t spccllkd nt-ccptublc system mdionuclido relense spccilic.l 11cccp1ublc system mdionuclidc relc11se design forward in the development oflhe modular HTGR dcsigll limits uro no1 c~cccdt'll durill!J m1y condition ol'nonnul limits (St\RRDL). which limits the nmount ofmdionuclide design criterin. Howe\'er, the chunge in the definition of opcmtion. including the cllt-cts oramidpt11ctl opcra1ionul inventory thal is relensed by the fuel nml surfoccs within the the SARRDL. rcplncin!,l "core'" with "system:* is

()CCllt't'CllC\'.'S, helium cl1olnnt bmmdnry under nomml nnd AOO conditions. problematic. The NRC nppnrentl~* expmided SARRDL The "system" refors to the componems and imemnls of the applicuhility lo the em ire reuctm* helium pressure ml ITGR helium pressure boundnl)'. Design fcn11n'Cs within houndury mthcr just applyiug it ns u mensurc ofpurticte the 1'Cnctor system must ensure lhnl the St\RRDLs tl\'c not lhel conling etfoctiveness. ln uddition 10 the conccms exceeded during normal opcrntions und t\OOs. cxpt'Cssed below, use of"systcm'" could he misimerpreled in the future 10 include systems such ns The 1ris11*uclm'lll isotropic (TRISO) fuel used in lhe mHTGR the helium puritkntion system.

design is the primnlJ' fis.*ion pmduct bnrricr nnd is expected 10 hnve n VCI')' low incremenlnl fission product relense during The ra1ionnle for this criterion. nnd the NRC staff AOOs. presenlnlion of02/22/l 7 to the ACRS Subcommiuee.

indicutcs tlmt lhis chnnge is intended to cnplure the iden t\s noted in NUREG-1338 (Ref. 3) nnd in the NRC stall's thnl mdionuclidcs 1ha1 deposit, or plnlc out, on the fc<'\lbnck on the Ncxl Genemtion Nuclcnr Plnnl (NGNP) internal surfoccs of the t-cnctm* helium p1'Cssurc boul\dUI')'

pmject white pupcr. "Next-Genern1ion Nucleur Plant - cnn be 1'0-entrnined durin1,1 nonunl t1pemtions or AOOs, Assessment of Key Licensing lSSlu~s" (Ref, 11} the TRlSO nm! thnt such fl'-cntminmenl needs to be taken hno l\iel tission product transport nnd retention behavior under nil account in nsscssing whether the SARRDL is exceeded.

expected opcmting conditions is lhc key 10 mec1ii1g dose limits. as u dilTerent nppn1nch to defense in depth is While this is conceptunlly lrne, in foct the amount of re*

employed in nn ml ITGR. The SARRl)I. concept ullows for cnlrninmem 1hn1 occurs durin!,l au AOO is negligible.

some smnll incl'Cnse in drculnting mdionuclidc hwentol)' Experiments to measure R':-<cntmiument under during un AOO. Tl1 ensure the SARR[)l. is nol violnted dcprossurizn1ion conditions have shown thnt re-during an t\00, u nomml operation radimmclidc inventory el\lmlnmenl is n function ofsheor rntio. Shcnr mtio is the limit must nlso he es1nblishcd (i.e.. nppropritllc mnrgin). 'l11e mtk1 oflhe maximum helium shcnr force during u mdionuclido nctivhy cll'Culnting within the helium coolmit lrtmsient event to the shcnr foree oflhc flowing helium boundnry ls continuously monitored such tlmt the nonnnl nl nny !,liven locntion during nonnnl. IUll power opcmtion llmhs uml St\RRDl.s U\'Q not cx<.'\.'Cdcd. opcmlit1n. t\s described in the NGNP Mechnnislic Smn'Ce Terms While Pnper. which is listed ns n 1-cfcrence The SARIO)!_, wilt he eslnblished so lht\l lhc most limiting in the dmtl N!,lUlnlm')' guide, in-situ mcas111'Cmcnts of rt'-

license-basis own\ does nol exc1.'Cd the sitillB regulntory dose cnlmhuncnt vs. shear mtio indicntc thnt re-entrainment DOE/N!l\jon!ll L!lbo111101y Tcum Comments on DrnO R9g11lfl!oty Guide DG-1330 - Docket ID NRC-2017-0016: Page 24

CrltQriOll 201? NRC mHTGR*DC Title and Coul\\nt 3017 NRC Ratlom1lel! Ttnm Commtnts limits criteria at th<> eKduslon urea boundm-y (EAB) and low* ofmdionuclldes greate1* than l % does not occur until th<>

population zone (LPZ), and nlso so that the l 0 CFR 20.130 l shear mtlo reaches 5, annuuU<Wd dose limits to the public are not ei1cwded at the EAB tbr nomml operation and AOOs, As dlscuss~'tl in tho Preliminary Safety lnfonnatlon Document (PSID) for the Geneml Atomics MHTGR, the TI1e NRC has not approved the concept ofrepluclng peak shear mtio expected for the design basis speeltied acceptable fuel design limits with SARRDLs, The depressurizatlon event ls I.15, This design basis evem concept of the TRISO fuel being the primary fission product entails a breach of the reactor vessel pressure reliefline, bm1*ier is intertwined with the concept of a functional resulting in an opening of 13 ln2 and a deprcssurillltlon contalmnent for mHTOR technologies. Sec the mtlonale for in a period of minutes.

mHTOR*DC 16 fol' funher lnfomllltlon on the Commission's curreut posltlun. For the largest breach ln the helium pres.~ure boundary that would be expected to fall within the spectmm of the The wo1'11 "coolant" has boon replaced with "heat removal," AOOs (failure of an instmmentution line equh*alent to a as helium coolant invento1r control for nonnal opemtlon and breach of less than one square inch, resulting in AOOs is not n<>eessary to meet the SARRDLs, due to the depressurizatlon over a period of hours), the changes in reactor system design. helium flow velocity and in the shear forces on the reactor helium pressure boundai)' surfaces result in shear 1-atlos less than one, When the reactor is stoned up from cold shutdown, the shca1* forces amund the helium pressure boundary are lower thun those during nonnal, full power opemtion, so the shear ratios in th ls case are also less than ono, lnslgnlticnnt ~'-entmlnment is e.xpootcd to occu1* when shear mtios ure less than one, It should be noted that csse111latly all fission product fll(lionuclides on the reactor helium pressure boundnry surfaces nre 01'iginnlly released from the core, The release ofactivation products from reactor helium p1'1lssure boundmy surfaces ls expected to be minimal compared to release from the core. Core rudionuclide release values are measured by gmb samples (plnteout uctlvity) and plnteout probes (condensed activity) for comparison with the SARRDL. Oross cireulating activity is also monitored continuously. It is not possible to distinguish mdionuclidcs that have been re-ent1-ained from other circulating activity thut is monitored or collected in n gmb snm11le, The SARRDL vnlue is set Inking into account the amount ofre-entrulnment that can occur during AOOs or postuluted nccidents, The DOE/Nationq! Lubm*nto!Y Team Comments on Draft Regulgtory Guide DG-1330 - Docket ID NRC-2017-0016: Page 25

C1*ltQ1*ion 2017 NRC mll'l'GR*DC Title and Content 2017 NRC Rutlmmles 'f~nm Comnumts vnluo is nlso set taking into nccount the foct llmt the plnteout inventory oflong-li\'l'<I rodionuclidcs will increase overtime to nu end of life maximum.

Due to all of the above considerntions. the definition of the SARRDL should be thnt which wns proposed by DOE/I NL: Specified Acceptnble Cur~ Radionuclide Relcuso Design Limit.

SARRDI, A11proval The Rntionnle states thnt the NRC has not yet approved the SARRDI. concept for replncemcnt of the SAFDL and refers to the rotionalc for modulnr lffGR DC 16 for informntion. Howe\'cr, the DC 16 rntionalc hns no link bnck to DC I0 aad the SARRDL, so it is not clear whnt this means. This pnrogmph should be revised so thnt tho relationship between the rcforenccd DC 16 discussion nnd this issue is clnrified. Clarification is nlso needed regarding whether release of the Regnlntory Guide will constitllle npprovnl of the SARRDL. nnd ifrelensc docs not constitute uppro,*nl. what funher steps would be m.'Cdcd to obtain approval.

12 S11('p1v.,slu1111(1\,'<lt'tm* fl'lll\'I' 11.w///111/1111.1" llelium in the ml ITClR docs nut nlTClCt renctorcore Sec SARRDL comment on mllTGR-DC 10.

Tlw l'cnctor core and assodnted control nnd prntcctlon systems susceptibility to coolnnt-induccd power osclllatim1s:

shnll be dosillucd to cnstn'll tlmt power oscillmlons thnt can thorefo1'll, n scpurnto mllTGR*speclllc DC is uppropl'inte.

result in conditions excc~'lling s1wdlit'd t1cct'ptublc system The word "cooltmt" wns deleted nnd the speclncd acceptable mdionuclldo release design limits lll'll not possible or cnn be foci design limits wcro roplnccd by SARRDLs. Tho reliably nnd readily detccll'<I nnd suppressed. discussion <Jn the S/\RRDI. is given in mHTGR-DC 10.

14 R(*t1t'lm* helium prt'.\WUI\! hurmdm:\', "Rcnctor cooltmt p1'1ls.-.1re boundnl'y" hns been relabeled ns Sec positive comment table.

The l'Cnctor helium prossul'c houndnr;* shall be designed. "reactor helium pressure boundm')'" to confonn to stnndnrd fobricntcd, erected. nnd tested so ns to have nn extremely low tcm1s used for ml ITGRs.

probnhility of nbnomml lenkuge. ofrnpidly propugnting foilure.

of gross 1"11pt111~. nnd ofunaccc1ltnble Ingres.~ of moisture. nlr, - lhu mllTClR-DC 14 nddresses the nc't'<l to consiucr lcakn1,10 secondacy coolant. 01* otlwr lluids. ofcontnmimmts Into the helium used to trnnsport heat from the l'CUCIOr to the heat exchangers for powe1* Jll'Oduction, residual hcut 1~movul. and process heat. The phmsc reactor helium pressure houndncy" encompasses the cntil'c volume containing helium used to cool the reactor. not just the volume within the reactor vessel. For consistency, a specific requirement is nppendcd'to ml*ffGR*DC 30 fora means of detecting ingress ofmoistui'll. air, sccondmy coolant. or other QOE/Nmjono! Lnbm11101y T9pm Comments Cm Drnl\ R9gulotory Gujdc QG-1330 - Dock91 ID NRC-2017-0016: Page 26

Crite1*ion 2017 NRC mtlTGR-DC Title oud Couteut 2017 NRC Ratlonnles Team Comments fluids. Althoush "other fluids" could he interp1'1lted as Including water and steam. for emphasis. the word "moisture" is included in the list ofcontamhmnts in both mHTOR*DC 14 and mHTOR-DC 30.

.IS Rt'<ll'ltll' lwllwn fll'Cl.l\'1/l'Cl ho11m/111y *\IWl~m tl~..1~11. "Reactor coolont system" hos been 1'lllobeled as "1'1lactor Removal of the Word "System" All systoms tlmt are port of the reactor helium pressure helium pressure boundary" to confom1 tCI stnndnrd tem1s The chnnses to tho text in tho body of this criterion made boundmy. such as the reactor system, YtIBsel system. nnd heat used for mMTORs. by the NRC stalfrelative to the proposed text in the romovnl systems, and tho nssoduted auxilimy. control. nnd DOE/INL l'llport are nn impmvement. However. the protection systems. shall he designed with sufficient nmrgln to word "System" should be removed from the title of the ensure that the design conditkms of the reactor helium p1-essuro criterion. The reactor helium pressure boundary is not an boundm)' are not l.'xceedcd during nny condition ofnomml individnal system, but rather is constituted from purts of operation. including nnticipmed operational uccurrences. several systems. which ore listed and referred to in the body of the criterion. Removul of the word "System" from the title will make the title consistent with modular HTOR tcnnlnology.

16 C<111t11ln111m1t design. The tenu "t\mctionnl contulnment" is applicnhle to udvnnced l*'11netlonnl Cont11h1me11t Polley Issue A reactor functionnl comalnment. consisting of multiple non-L WRs wltlmut a pressure retaining contninment Discussions of Commission policy decisions on bmTie1'S lntemnl nnd!or ei<ternal to the Nnctur und Its 1.'Qollng structure. l\mctlonal contnimncnt nt.'<.'<l to be worded cm-efolly. For system. shall be provided to em1trol the rolense ofmdl\:mclivity the modular HTOR. a pollc~ decision is not needed to the environment nnd to ensure that tl1e functional A functio1ml cuntalnment can be defined us "n banler. or set l'll!,tnrdin!! tbe !Jeneral aceeptublllty ofap1ilying a comalnment design conditions important to safe\)' ore nut ofbnniers taken together. that effectively limit the physical functional containment (radionuclide retention) approach ex~ed fo1* as long os postulatt.'<l nccldcnt conditions require. transport und release ofmdlmmclidos to the environment tlmt differs from a conventional I. WR high-press111-e, across n full rango ofnonnal operating conditions. AOOs. low-leakll!le structure. Howe\'CI'. bused on the SRM to and aecltlent conditions. SHCY-03-0047, a jllllicy decision is needed regarding the 11crfommnce criteri11 tt1 be applied to u fun ct ionnl Functional conmlnmcnt Is relied upon to cnsm'll that dose at containment. The infornmtion located in the mHTOR*

the site boundary us tt conmwenCll of postulated accidents DC 16 rationnlc com.-.:tly stntes thnt a policy decision meets reg11lntory limhs. Troditionul containmont structures rognrdin!J ftmctlonnl contuinmcnt performance also provide the 1-eactor and SSCs important to sufety inside 1'.'<)Uirements and criterin will he needed. It's noted that the containment structm-e protection ngainst uccidents !'elated contuinmcnt perfommnce criterin for I. WRs are provided to cidenml 111m1rds (e.g., turbine missiles. tlooding. nirerat\). in l 0 CFR SO Appendii.: J, rather thau in the ODC of Appendix A. The last two sentences in the rationale for The ml !TOR functional containment snfot)' design ol~iective ARDC 16 should be deleted.

is to meet 10 Cl'R S0.34. 52.7\l, 52.137, twS:!.157 olfsite dose requirements nt the plant's eKelusion awn boundary ~*unetloiml Contninmcnt Llln11ua11e (BAB) with nmr1:1ins. ARDC 16 should discuss "llmctionnl contuinment" with the mHTOR-DC rofc1Ting to the ARDC. See ARDC 16 The NRC staff has brought the issue of functional tettm comment.

containment to the Commission, und the Commission has found it 1:1cnerally ucccptablc, as indicated in the stuff requirements memoranda (SRM) to SECY-93-092 (Ref. S)

DOE/Nqtjonnl babot]tow Tcnm Comments on Drat\ Rcgulqtow Guidg DG-1330 - Docket ID NRC-2017-00 I6: Pl\ge 27

Critc1*lon 2017 NRC mllTGIM)C Title 111111 Content 2017 NRC R11tlo1111les Team Comments and SF.CY-OJ-0047 (Rot: 9). ln the SRM to SECY-03-0047 Fm1ctlonnl Containment l'erformnncc St1111dnrd (Ref. 10). tllQ Commission instructed the stnll'to " ... de\'clop Tho NRC staff notes in the next-to-Inst rntionnlc perfomrnnco l'l.'qlliromcnts and criteria work Ins closely with p11rng111ph that the staffhns provided fe<Xlback lo DOE industry cxpcl'ls (e.g.. designers. EPRI. etc.) and other on the use ofa functional containment as part of its stakeholders rogmxting options in this area. taking into rovicw of the NGNP. The rntionnlo shonld also note that account such fcnturcs as core, fuel, and cooling S)'stoms the NRC staff also stated in its assessment report tlrnt it design." and directed the stuff to submit options and finds tho DOE proposed porfonmmce standard for the rccommendntions to tho Commission for ti policy decision. modular MTGR functionnl contninment to be 1'Cnsonnblo.

This performance standard ensures the integrity of the The NRC' stnffnlso provid<XI feedback to the DOE on this fuel pm*ticlc bnrriers rather thnn to allow significant tucl is.~ne ns pm1 of tho NONI' pN.~jcct, In the NRC staffs particle foihn'Cs and then to rel)' extensively on other "Summm-y l'ct.'\lback on Four Licensing Issues NGNll" (Ret: mechanistic bmTicrs.

11 ). the nro11 on l\mctional containment and l\iel dc\'elopment nnd q1mlitkntlon nott.'\I \hilt " ... 11pprovnl of the pn.,posed nppronch to functional containment for the mHTGR concept.

with lts cmplmsis on pns.~ivo safety fcntm'Cs nnd rndimrnclide retcnti\ln within the filol over u broad spcctrum l1t'off-1mrm11l conditions, would necessitate thnt the l'l.'qllil'l.'\I fuel pnrticlc 1mformm1cc cnpabllitks be demonstrntcd with 11 high deg1"Co ofeertnint)'."

GDC 38, 39, 40, 41. 42. 43. 50, SI, 52, S3. 54. SS, 56. and 57 nre not npplic11ble to the mHTOR design. since they address design crltcri11 for prossun.'-rotnining contninments in the trnditional t. WR sense. Requh'Cments fo1* the perform11nce of the mMTGR 1'Cnctor building m'C addressed by new Criterion 71 (design basis) and Criterion 72 (pl\wisions for pc1*iodic test ins 11ml inspt.'Ction).

17 E/cu.,*11*/c: f>OH't..'I' systems. A 1'Cli1tble power system is 1'.'QUirod for SSC's during Use of the Wo1*d "Systems" Electric power systems shnll be provided to pem1it fonctioning postulated occident conditions. Power si*stcms shall be Based on the ACRS discussion of02/22/l 7. we might of structures, systems. tmtl C\lmponcnls impm1nnt lo snfcty. sufficient in copncity, capability. and rolinbilit)' to ensure wish to request incronscd clarity on what is intended The sufcty fonction for the systems shall be to pro\'idc vitul snfct)* t\mctions t\l'C maintained. The emphnsis is plnc<XI when the plum! "systems" is used with respect to sutlicicnt cnpncity. cnpubility. and relinhility to ensure thnt on requiring reli11bility of power sources rnthcr thun duplicate and independent power supply. As written (I) spt.'Cilkd ncccptublc systcm rndionuclidc release dcsig11 pt'Cscribing how such rolinbility c11n be uttained. The now, multiple independent systems ore more implied limils und design conditions of the 1'C11ctor helium pressure 1"Cfe1"Cncc to onsitc vs, olfaitc electric power systems wus mther than explicitly stntcd in the DC',

boundury nro not exceeded 11s 111'Csult ofuntidpaled deleted to prol'ide for th\1sc l'Cactor designs Ihm do not operntionnl occurrences and (2) vital functions that 1'Cly on depend on offsitc power for the fonctioning ofSSC's electric power are maintained in the event ufpostul111ed important to snfcty.

uccidents.

'The onsitc electric power systems shall hn\'e sufficient 'The text related to" ... supplies, including batteries. and the independence. redundancy. and test11bility to perfonn thch* cmsite distribution S)*stcm." was deleted to 11llow increased sofot)' l\mctions, assuming n single foilure. tlcxibilit~* in the design of offsite power systems for DOE/Notjonol Luborntol'y Tcum Comments on Drut\ Rcgulotory Guidg DG-1330

• Docket ID NRC-2017-0016: Page 28

Crltc1*lon 2017 NRC mUTGR-DC Title 111id Content 2017 NRC RntlomtlCli Team Comments ndvm1e1.'<1 rcuctor designs. However. such onsito systems are still expected to rcmnin cnpable of performing assigned safety llmctions during accidents as a condition of requisite reliability. "Reactor C\lolant pressure boundutj"' has been relabeled as *~vactor helium pressure boundary" to conform to standnrd terms used for mHTGRs.

Tho specllioo ncccptnblo fuel design limit hllS been replaced with the SARRDI.. Tho discussion on tho chnnge to SARRDL is l!iven In mHTOR-DC I0.

Thi.' e:dstins sin11le switchynrd nllownnce remnins nvnilnble n11dc1* ARDC 17. lfn pnrticulnr ndvnnccd desisn requires the use ofGDC sinsle switehynrd allownnco wording. the designer should look to GDC 17 for guldnnce when dcvelopin11 PDC.

lfelcctrlcnl power Is not required to pcnnit the llmctiouing of SSCs impm1nnt to snfot)'. the rcquhvments In tho mHTOR-DC nrc not npplicabhi to tho design. In this case, the functionnlity ofSSCs importnnt to sutbty must be fully evnlunted nm! documented in the design buses.

18 J11.<p111;tl1m 11111l testl111l t!f~l<"*11*ic power .~1wrems. ODC IS is o design-independent companion criterion to R11tlon11lc Wording Inconsistency SnmensARDC GDC 17. Pnrogmph two of the mtionn.le rcfors to the deletion of Electric power systems importnnt to snfety shnll be dcsisned to words pertaining to ndditionnl system exnmples. but pem1i1 t1ppro1irinte periodic Inspection nnd testing ofimportnnt Wording pertaining to ndditionnl system cxnmples hns been there do not appear to be nny such deletions from the nrens nnd fontures, such us wiring, insulntion, connections, nnd deleted to nllow inc1vnsed t1exibility nssocinted with vmious text of the criterion.

switchboards, to nsscss the continuity of the systems and tho designs.

condition of their components. The systems shnll be designed with n cnpnbllity to test periodically (I) the operability and Tho text relntcd to the nuclcnr power unit, ollSite power functionnl pcrfommnce of the components of the systems. such system, nnd onsito po\\vr system wns deleted to be consistent us onsite power sources, rclnys, switches. nnd buses. und (2} with mHTGR-DC 17.

the opcrobllity of the systems us n whole nnd, under conditions ns close to design us prncticnl. the full opcrntion sequence thnt brings the S)'stcms into opcmtion. includin11 opcrntlon of oppllcublo portions of the 11rotection system. and tho tmnsfor of power nmong systems.

26 Rc11c1M1y mlllm/ SJWlems. Recent licensins uctivity associated with tho npplicntion of ARDC Sco11e Changes SnmensARDC ODC 26 nnd ODC 27 to new reactor designs "Response to Item (I) seems to hnve n nnrrower focus than the ODC, Reactivity contml systems shnll include the followin1:1 Gnp Analysis Summnlj' Report for Reactor System Issues." focusins more on shutdown cnpability tlmn on 1vnctivity capnbllhics: (Ref. 26) nnd "Response to NuScalc Gap Annlysis Summary control nnd docs not nppea1* to rotlect the requirement of Report for Rcactholty Contml Systems, Addressing Onp I I, GDC 26 to hnvc two renctivity control systems for General Desl1:1n Criterin 26," (Rof. 27), rc\'cnlcd thnt controlling renctivity for nomml operations and AOOs.

!)OE/Nutlonq! l.abomtmy Te!lrn CommeQ)s on Dmtl Regu!qtmy Guid9 PG-1330 - Docket ID NRC-2017-0016: Page 29

Crltv1*lon 2017 NRC mllTGR*llC Title ond Content 2017 NRC Riltlonnles Tenm Comments (I) A meuns ofslmttins down tho n.'llctor shnll be pmvided to ndditionnl clnrity could be provid1.'d in the nrea of reactivity In uddition, Item (2) of this combined design criteria ensul'C thnt. under conditions of nomllll opcl'llticm, control requirements. ARDC 26 combines the scope ofODC t'CQnh'lls two independent and diverse menns of includins miticipated opcl'lltlonnl occurrences. nnd with 26 nnd ODC 27. The development of AROC 26 is infom1ed achieving nnd mnintninins sntb shutdown under design*

npproprinte mml\hl for malfunctions. design limits for by the proposed Genel'l\l Design Criteria of 1965. AEC*R bnsis conditions whereas GDC 27 seems to ullow n fission product bnrriers nre not o:\eecdcd. 2/49 tmd November S. 1967 {32 FR 10216) (Ref. 28): the collective nud combined capability.

cummt ODC 26 nnd 27: the definition ofsnfcty*l'Clnted SSC

{2) A means ofshutling duwn the 1-eactor and mnlntnining n In 10 CFR $0.2: nnd SHCV-94.084, "Policy tmd Technical The e:\isting l'lltionalc does not cllplicitly e:\pluin thc sntb shutdown under design*bnsis event conditions. with Issues Assoch1tcd with thu Regul11tory Tre11tmont of Non* nppnrent scope changes that occurred in the tl'llnsition appmpriate mul'!lin for mulflmctlons. shull be pmvlded. A Safetll Systems in l'as.~ive Plmn Designs" (IM'. 29): and the tl'Qm thc original GOC language to the current ARDC 26 second means of1'Cllctil'lty conll'Ql shall be p1'Qvl1k<d thnt prior n11plkution ot'1vnctivity contml r-'Quiremcnts. lansuugc. 111c rutiom1lc should be re\*iscd to include an Is independent, divct'SC. und capublQ afnchlevins und c1111lanation for the apparent scope changes. In udditlon.

mnintninins sufc shutdown under dcsisn*bnsis event Currelll OOC 26, tlrst scnwnw. states thut two reuctivity a chansc in the title. such as Recl<'//l'/~1' C<Jntrol System conditions. control s;;stems lll\lifferent desisn principles slmll be S/111td11w11 Capahllll)'. would better ulign the ARDC und provided. In addition, the NRC has not licensed a power its title.

(3) A system for holding the retictot* snbcritical under cold reacto1* thnt did not provide two Independent means of conditions shull be providt/d. shutting down tho 1'Cllctor. AROC 26 Item (I) nlso includc:d the replucemcnt of "llJl<'<'lf/ed tlt'(,-eptable ,lite/ ileslgn llmlt.~" with "desli.:n

( l) Current ODC 26, second sentence, states thnt one of the //111/ts.fi>1',//,"'~i11n J>1'0(/1wt liurl'i<'t\\'." Tho discussion in tho l'CUctiYity control S)'Stcms shall use control mds and shttll be mtionale nnd tho NRC stnffprescntation ofl'ebrunry ~2.

capnble ohelinl>ly controlling reactivity chnnses to ensure 2017, indicnte that the focus of this chunge is on both the thnt. under conditions ofnonnal operation, including AOOs. foci nnd the 1vnctor coolant boundury. Addition of the nnd with appropriate mnrgin for mnlfunctions such us stuck reactor coolant boundary is un increase in scope from rods. spwlfied neeeptnble fuel design limits lll'C not ODC 26 relative to what needs to be protected fmm exceeded. Tho stnfflwognizes thnt spwifying control rods failure during nonnal operation and AOOs. This chunge mny not be suitable for ndvru1ced reactors. Addltionnlly. is inconsistent with the foct that some AOOs could 1'Clinbly controlling 1vactivity, us required by GOC 26, hns involve failure offissio1i product bal1'icrs (e.s., failure of been intcrp1-etcd ns cnsurins the control rods nre capable of instnimentatiou lines, sample lines, etc.). Furthenuorc, rapidly (i.e.. within a lbw scco,nds) shutting down the reactor nothing is provided in the rationale 10 prevent future (Rct'.27). interpl'Ctations of the language as also encompassing the reactor containment for those designs that use n The stnffchm1gcd control rods to "means" in recognition that tl'llditionul approach to containment. All of these points advanced reactor designs mny not rely on control rods to need clarification.

l'llpidly shut down the reactor (e.s.. ultcrnutive system designs or inherent fccdbuck mcchunisms muy be relied upon ARllC Development Refc1*cnces to pcrfonn this function). Additionallv, "spc..'Citk'd ucceptnble 1110 lirst pul'llgl'llph of the rntionalc notes that the fuel design limits is replaced with "desisn limits for fission development of ARDC 26 wns inforn1cd by a number of product barriers" to be consistent with the AOO acceptance references. Most of these references pt'Ceetlcd the cutTCnt criteria. ARDC l 0 and ARDC 15 provide the appmpriatc version ofthe GDC. An explanation of how these older design limits for the fuel und reactor coolant boundm)'. references supported the clmngcs from the currcm GDC 1'CSpcctively. A non*LWR may not necessarily shut down would be helpful.

l'llpidly (within seconds) but the sl111tduwn should occur in a time frame such thnt the fission product burricr design limits OOB/N!ltlono! Lqhm'!!tory Tupm Co1rnnqnts on Dmtl Regu!otorv Gujdc DG-1330 - Docket ID NRC-2017-0016: P!lgc io

Crltc1*lo11 2017 NRC mHTGR*DC 'fltlc 1111d Content 2017 NRC Rallomlles Team Comments ore not cl\ceeded. In regm'tls to sufcty clus.~. the capability to Use of "Design-Basis Event" L11n11uagc shut down the reactor is ldimtified as a tlmctlon perfonued by It is not clear why the wordlnl! "dcsilln*basis event safety-related SSCs in the 10 CFR SO.:? definition of safety* conditions" is used el\plicitly in Item (2) whereas related SSC's. p(ls\ulated accidents" is used consistently for the rest of the ARDC/SFR-DChnHTOR-DC sets.

(2) Current QDC 27 stutes that the reactivity control systems shall be deslsned to have a combined capability ofwliabl)' Bnsls for Operutlonnl R<<tuh*ement controlling reuctil*it~* chanses to assure thut, under postulated The wtbwnce should be provided where the statT accident condltloos and with appropriate margin for stuck ldentilled the requirement \hut the third sentence ofODC rods. the capublllty to cool the cow is maintained. Reliably 26 is considered to be an opemtional t'Cquiremcnt and controlling reactll'lty. as required by ODC 27. requires that not relevant as a DC.

the reactor achlo,*e and nrni111ain satb, stnble conditions.

including sub~ritlcnlity. using only safot)' related equipment with margin for stuck rods (Ref. 26). The Orst sentence of ARDC' 26 (2) wtbrs to the satbty-relnted means (systems and/01* mi.'ilhanisms) 10 nchleve and iunintnin stile shutdown.

"Mnlntaln snlb shutdown" indicates subcriticuUty in the long tenu m* an t.'qullibt*lum condition naturally nchievcd by the design.

TI1e staffchangt.'Cl "reuctlvity control systems" to *~uenns" in recollnition thut advnnced reactor designs may rely on a system, Inherent !Cedback mechanism. or some combination thereof to shut down the reactor and mnintain n safe shutdown under dcslsn*basls event conditions. SECY-94*

084, "Policy ond Teclmicul lssues Associated with tho Regulatory Treatment of Non-Safety Systems In Passive Plant Designs" (Ret: 29). describes the characteristics ofa safe sh111down condition as reactor suberitlcallty. decoy heat removal, and radiouctive matcdnls containment. The staff replneed postulated accident conditions** with "desilln-basis event conditions." to emphasize that plants aro l'.'quin.'tl to maintain a safe shutdown fullowhl!! AOOs us well us pClstulnted nccldcnts.

The second sentence ofARDC 26(2) refers tCl a means of uchievins nnd nmlntainins shutdown tlmt is lmpo11ant to safety but not neccssnrily safety relnted. The second means of reactivity control serves as a backup to the safoty-related means and. as such, nmrsins for nmil\mctions tire not t'Cqllired but the second means shall be highly reliable and robust (e.g.. meet ARDC l.*S). "Independent" Indicates no

!)Oll/Nntlongl LgbO!'mory Tc11m Comm@ts on Qml\ Regul11tory Gujde QG-1330

• Docket ID NRC-20 )7-00 l 6: Puge 31

Crlte1*lo11 2017 NRC mU'fGR-DC 'fltle 1mil Co11tc11t 2017 NRC Rotlomlles 'ream Comments shurcd systems 01* componunl~ with the satbty-rolated means and "diverse" indlcntos n difforent deslsn thnn the sufoty-related means. The pmllose ofon independent nnd diverse mwns ofcuntrollins reactivity is to lll'l.-clude n potential cummon cause fulluro affecting both means ofl'cnctivity comrol. which would lead to the inability to shut down the reactor. The s1.-eoml means ofrenctMty control does not hnvc to dmnoustrnto tlu\l design limits fur fission product bnrrieni nro met.

Addltionnlly. the Clll'fllnt GOC ~6. third sentence. stntes that the second roncth*ity control system shall he cupnble of reliably cuntrollins the rote ofch11nges rosultins from planned, nonnul pDwer changes (including xenon burnout} to assure acceptable !\tel design limits nro not ci.:cecded. Staff hus identified this as an operational roquiromcnt thut is not nccessury to ensuro reactor safety provided n design complies with ARDC 26( I). Therefore, this sentence is not retained in ARDC26.

28 Retie/Mt)* 1/111//.I', "Reactor coolant p1vss111v boundary" has been rolnbeled as See positive comment table.

The reactor cure. including the roactivity control systems. shnll "reactor helium press111v boundary" to con fonn to standard be desisned with appro1niate limits on the potential amount tcnns used for mllTGRs.

nnd rnto ofrcnctivity incrcnse Ill cnsuro that the effects of postulated reactivity accidents cnn neither (I) 1vsult in damage The list of"pustulated reactivity accidents" has been deleted.

to the rouctor helium pressure boundary greater than limited Ench design will have to dcte1mine its postulated reuctivity local yielding. nm* (2) suffickntly disturb the core, its sup11ort nccidents bused on the specific design and nssociutcd risk stntctures, or other reactor vessel intcmals to impair evaluation.

sisniflcnntly the capability to cool the co1v.

30 Q11a/lry uf1v:1wtor /le/111111 f>l'l!SSlll'C hu1111tl<1r>>. "Reactor coolnnt ptvssure boundacy" has been relabeled as Sec positive comment tnble.

Components that are part of the reactor helium pressmv reactor helium pressure boundary" to cunfonu to sttllldard boundUl')I shall be designed, fubricnted. er1.-eted. nod tested to temts used for mHTORs.

the highest quality stnndnrds prncticnl. Meuns shall be provided for dett.'Ctlng nnd. to the extent l>rnctlcnl. ldenti i)'ins the Thu mHTOR-OC 14 uddtvsses the net.'<! to consider leakage locatiun of tho so111vo ofronctor helium lenlruge. Menus shall ofcontnminnnts into the helium used to trnnspurt hent from be pmvided ftw detecting ing1vss ofmoist111'll, air, scconducy the t\lactor tu the hcnt l)l(Chunsc1'S for 11owcr pmduction, coolant, or other fluids to within the 1vactor helium p1vss111'1l residual hcnt 1vmQvnl. und process bent. The phrase reactor boundary. helium pressure boundary" encompasses the cnth'll volume cuntaining helium used to cuol the reactor. not just the volume within the reactor vessel. Fur consistenc)'. n speclflc l'll\JUircn1cnt is nppended to mHTOR-llC 30 for n meuns of dctectins, ingNss ofmoistUl'll. air. sccundat')' coolunt, or other QOE/Nqtlonol LQbOl'!\tOl'V Tcgm Comments Oil Drnfl Re!lulotorv Gujdg DG-1330 - Pocket ID NRC-2017-0016: Page 32

Crlto1*lo11 20t'1 NRC mHTGR-DC Title 1md Ctmtlmt ' 2017 NRC R11tlo1111les Team Commeuts*

tl11lds, Althm1Qh other tl11lds" cuuld be l11terproted as lncl11ding water and steam. fm* emphasis, the wmd "molstm'll" ls ind11ded In the list ofoontnmhmnts in both mHTOR*DC 14 und mHTOR-DC 30, JI l'hKWtre p1'l!w11tlu11 q/'re11r1m* /m/1111n pre.~~111'1! huwlllm~>> "Reuctm' coolunt pross11re bo11ndacy" hus bn rolabeled us Coohmt Chemistry Tho l't.'llCtor helium p1'llssuro boundncy shall be desl9ned with reuctor helium pressm'll boundary" to 1.'0nfunn to standard The stuffhns added "coolant chemisll-y" to item (2) in sutllcient margin to ensure that. when stressed 1mde1* ti11erntlng, terms used for mHTORs, the critQrion. and the second purngrnph of the rationale muintenance, teslill!!, und posmluted necldcnt 1.'0nditim1s. t'llfers to "unique potential coolunts." The working fluid (I) the boundary behaves in a nonbrittle mmmerand (l) the Spccitlc examples ure addt.'11 to the mHTOR*DC' to account in the modular !HOR is helium, which is chemicnlly probability ofrupidly proplll:lating fmctm-e Is minimized. The for the high design and opemtin9 temperatures mul unique inert. Concerns regarding "coolant chemistry" in design shnll t'llflcct considerntion ofservice temperutures. potentiul coolants. HTGRs pertain to the effects ofconmmhrnnts on sel'Vice degrndallon of material prope11ies, creep, fatigue, stress muterial properties.

mpture, and other cunditions of the bouudacy mnte1*iul under operating, muintenunce, testing. und postulated accident Item (2) in lhe criterion should be changed to. "(2) the conditions and the uncertainties in detcnnining (I) muterial effects ofim1dintion and helium contaminants on properties, (2) the elllx:ts ofim1diution und coolnnt chemistry material prope11ies,".

on moleriul properties, (3) residual, steady-state, mul tmnsicnt strosses. and (4) size oftlows. TI1e last three words of the rationale should be replaced with, "potential helium contaminants".

32 lnsfJectlm1 qf're11c1or lta//111111>1'f!.*.w1re h1111nd111y. "Reactor coolant pressure boundary" hus bn nilabeled us Addition of the Wol'tl "Functlom1l" Components thut m-e part of the reactor helium p1'llssure reactor helium pressure boundary" lo confom1 to standard Replacement of "tesli11g" with ':ftmct/01111/ testing":

boundary shall bo desi9ned to pcm1it (1) periodic inspection tenns used for mHTORs. infonnution should be ud(l\.'d to the rationale lo exploin and functional testlns of lmportm1t ureas und features to ussess the intent behind the addition of the wont "jime1io1111/,"

their structural und leuktight integrity, and (2) an appropriate The staffmoditled the I.WR ODC by replucins the tenn 1110 word is not included in GDC 32. The rationale for material survcillunco pro9mm for the roactot' vessel. "reactor pressure vessel" with "t'llactor vessel," which the the criterion (and for the ARDC and SFR criteriu) does stuff believes is n more generically upplicuble tenn. not address this change in wording and does not explain whut is intended by fi11wtlm111/ tesllnR." Either an A non-lcaktight system nrny be ucceplnblc for some designs c.xplmrntion should be provided in the three rationales or, provided thttt ( l) the system lcnku90 docs not lmpuct safol)' prefcmbly. the won! ./i111c1/u1111r should be deleted.

functions under all conditions. und (2 l leuklll:le is cunsistcnl with SARRDL, "Le11ktl11ht" vs. Allowable l.mknge TI1c inclusion of the wo1~ls "1111d /~JkliRltl" in the criterion is not necessary when "strtwh1rttl lnwg1*ity" is sutllcient to describe _the requirement. The allowable leak role for a given design should be one of the aceepluncc criteria for the test for "stru<<t11ml i11tegri(v."

The words "11nd la11kligltt" should be deleted here and in the ARDC ttnd the SFR versions of this criterion.

34 l'tk~slvc t'l!.l'fd1111/ /1~11t l'ttnttn'lll. The wm~l ')1ussive" was added, OOSQ{I on the definition ofa Passive '18. Active Rcslthml lle11t Remo"nl A passive system to rcnm1*c reslduul heat slrnll be provided. mHTOR. In definitions Scellon 3.1 of the DO.E report titled To ensuro thut the first line of the criterion is not For nomml operations und nnticipnted opemtionnl oecurrences. "Ouidnn1.'l.l for DevQloping Principul Design Cl'itcrio for interpreted us requiring that the residual heat removal DOE/Nationol Labm11to1Y Teom Comments on Draft Regulatory Guide DG-1330 - Docket ID NRC-2017-0016: Page 33

t'l'lto1'ion 2017 NRC mHTGR-Dt' 'fllle tmd t'ottl'!lt 2017 NRC RlltlonnllMI TQ11m Comments the systwn sulbty funcllon shall bQ to tmnslbr tlsshm product Advanced (Non-Light-Water) Reactors" (Ref. 17). the system upemte passively during mmnal opemtlons and dccll)I heat nnd other Nsidual hent fi'Um the t'Qllctor core to an mHTQR design has a low pllWQl' density and henco rusidual AOOs. tho tlrat parogmph oftha mtionule should note ullimate heat sink at a rote such thut spt~clfl~d ucce111uble hl.'nt is i'Qmowd by u passive system. that the system may 01wn1te activdy for lieut removal system mdiouuelide ruleuse design limits mid the design during nonual opemtions/AOOs. but tlmt it shull operate conditions of the reuctor helium llNSSUre boundm')I m'll nt>t "Ultimate heat sink" hus l>een added to oxplnin thnt, if llUSSively during postulated accidents.

exceeded. mHTOR*DC 44 is deem*'<! not applicable It> the design, the residual hent l'Qnllwnl system is then roquirud to provide the EITeetlve Core Cooling During postulated neeidents, 11111 system sntbty 11.mction shall hent removal path to the ultinmto heat sink. ln the second pamgmph of this criterion, NRC staff'has provide e!Tuctive coN c.ot>ling. changed tlie words "effe**l/\'e mt11/11g" submitted by "Renctor coolant pressure boundm)*" has been rulnbeled ns DOEiiNL to "ej/ix:til'f: <'Ol'<l t,'tla//ng." DOE/INI. used the Suitable redundancy In components nnd features and suitnble "reactor helium pressure boundncy" to confom1 to staudnrd words "t'}/c**llw <'@ling" because it is not just the core intereotmections. leak detection. nnd isolation cupabilities shall tcnus used for mHTORs. that needs to be effectively cooled during postulated be provided to ensui-e the system safety 11.mction can be accidents, but nlso structural components such ns the accom11lished. nssuming n sln11le failm'll. The SARRDL l'l!pluces the ARDC specillcd ncceptable fuel core bun-el and the 1-enctor vessel. Effective cooling for dcsi11n limits us described in the rntionale to mHTQR-DC l O. these components is needed to ensure that a pnssh*ely coolable geometry is maintained. The word "ca/'e" The mHTOR*DC 34 incorporntes th11 postulated accident should be delctt.'<1 from the criterion.

residual heut removal requh-ements contained in QDC' 35.

To explain the basis for changing effective core Bffeetlve core cooling under postulated accident t.'Onditions cooling" to effective cooling. the followin11 paragraph Is defined us mnintaining fuel tempemture limits below should be added to the mtionule:

design values to help ensure the siting re11ulatocy dose limits criteria at the exclusion ai'l!a boundncy (EAB) and lmv- The mt>d11/ur HTGR rosld11al heat romow1/ >y.w111 population 1.0ne (LPZ) aru not exceeded and n geometry is prntct!ls the /11tegrlt1* oftlie <'Ol'C. the om'C! s11*1wt11rol preserved which supports residual heat removal. t'Ompommts, atul'thc rt.1 a1..~tnr \'CSS(ff when m1t:t:.fed under fH>.~hlltlled 11cclde11t C'0111litlo11s, thel'ehy he/ping Ill The QDC reference to electric power was removed. Reier to a11s11rc that lhe goomclt)' 1'C!q11i1wJfor pass/1'<' heat the rntionalo foi* ARDC 17 on electric power systems. l'<'nmwtl ls 11111i111a/nctl 7'/ie1'1<,fi1rn, "mnt etio/ing" was rop/aCIJd with "**oo//11g" to 1'q/lect the hraatlm* range of ne<:cssary <'tlf*liog prnvided by the S)Wt<-111 t/11/'lng po..*111/oted atv::ltlent.1'.

Rotlonale for Ultlmote Heat Sink

'l'h<l second porngruph ofthe rationale. which explains the busis for adding the words "11/tl111at<' heat s/11k" to the c1*iterion, is tuken from the rntionulo for ARDC 34 tlmt was provided in the original DOFJlNL submittnl. As it is written heiv. the second pnrngmph is tied to the possible need foi* a system like that nddressed in GDC 44.

In the case of the modular HTGR version oftha criterion, "11/1/11111te iieat sink" was added to the criterion by DOE/INL only for consistency with the ARDC and QOE/Natjgnnl ybgrntgrv Tenm Comments on Draft Regulatory Guide DG-1330 - Docket ID NRC-2017-0016: Page 34

Crlte1*ion 2017 NRC mHTGR-DC Title und Cnntl.'nt 2017 NRC Rationales Team Commen'ts completenes.\, and the second paragraph wns intentionally not included by DOE/lNL in the modular HTOR DC 34 rationale. 111e pumgraph was not included because modular HTGRs. unlike LWRs. SFRs, nnd possibly other advanced non-L WRs. do not hnve or need n system thnt corresponds to the Cooling Water System thnt is requin.'tl by QDC 44. The stnffseems to hnve incorrectly nssnmed that the paragraph wns omitted in error by DOE/INL and that the pnrogroph needs to be added to tie into n system like that addressed in GDC 44.

The paragraph should be deleted from the modular HTGR rationnle. and Criterion 44 and its associated criterion for inspection, etc. should be listed ns "Nlll Appllet.1hlo Ill tllu mud11/11r llTGR."

Detlnltlon of Effective Core Cooling The next to last pnmgmph of the rationale provides n definition of"effective coru coolins under postulnted occident c,onditions. It is not clear why the stnffhas added this pamsroph here but not done so in the ARDC or in the SFR DC. !'or the modular HTGR. effective

~'OOling is not just a matter of fuel temperature. \mtalso of time nt tempel'!lture. As it is written, this paragraph could be intorpreted by t\tlure regulators ns rl.'quiring n specitk temperature limit. or n "dosign rnlue." under ucddenl conditions. Such n requirement m!l!.l!l..ll21 be nn accurate rellection ofthe effects of foci temperature on conted particle fuel perfonnancc. Either this se,ction of the rationale should be deleted (prefem:d), or etR-ctive cooling should be defined in the ARDC and SFR DC versions of Criterion 34.

35 E111e~11cy 001'(! tYm//nl(. In the mHTOR design the power density und large length to Suggested Rl\tlonale Wording Change Not applicable ttl mHTOR. dinmeter ratio are such that muintuining the helium eoolnnt The decision to classify Criterion ~5 l\S not npplicable to inventory Is not necessm')I to mnintuin effi:ctive core cooling. the modular lffGR is correct. However, the rationale Postulated occident heat removnl is nccomplished by the cites the reactor power density and the core length-to-l'l.'Sidunl heat removal system described in mHTOR DC 34. diameter ratio as the l'easons that maintaining helium inventory is not needed. The power density and core geometry are only two of the reasons that might be listed. Others include, hut are not limited to, high graphite hent capacity and the high temperature capability of the fuel nnd the graphite. Ruther tlmn trying DOE/Nationq! LnbomtO!'y Team Comments on Drnft Regulatory Gujde DG- I330

• Docket ID NRC-2017-0016: Page 35

Criterion 2017 NRC mtlTGR*DC Title lllld Content 2017 NRC Rlltlonnh.,, Teum Comments to list llll of the fuctors thllt llllply. it would be better to 1wlse the first sentence of the rationale as follllws: "/11 tile mHTGR 1kwig11 malntc1/n/11g 1/w /1ell111i1 l11wn1m,* is 1101nt'*'<*ssary10 111a/111a/11 c.UiMiw roo//11g." Note thlll this suggested wording also deletes the word "con*."

consistent with the comment on the ratimmle for moduillr HTQR DC 34.

Jtl lllS/11!<'1/tm 1l{pt1~w/1*u nwlt/1111/ /w11111111wm/ ,~y.wm. The wtwd '))llSsive" WllS added. hosed on the definition ofa Edltorlnl Comment mHTOR. In deOultions Section 3.1 of DOE report titled In the first line of the cl'iterion. the word "system" The pusslve rcsldunl heat renuwnl shnll he desli!ncd to permit "Ouidm1ce for Devllloping Principal Design Criteria for should be inserted between the words removal" and appropriate periodic inspect km of importnnt components to Ad\'llnml (Non-Llght-Wntet*) Renctors" lRef. 17), the "shnll".

ensure the lnteyrity llnd enpabillty of the system. mHTOR design hlls u low power density and hence residual hent ls 1'\lmowd by ll passive system.

The ODC 36 system Is renmned nnd l'lll'ised Ill provide for inspection of the residual hellt removal s~stoms as required fur mHTOR-DC 34.

The list ofeKomples wus doleted. os they llppl~* to LWR designs nnd each specific design will ha\'C dlffilrent Important components ossodoti:d with residnlli hellt removlll.

37 resting *1f110sslw1 ro.~ld1111/ /lt'<1t l't'1111wol .~1w1em. Criterion 37 has beon 1'\lnllmed llnd revised fu1* testing the Lcoktii:ht vs. Allowohlc Lcokai:u passive residual heat remo\'ul s~*stcm rcquh'lld by As in mHTGR-DC 32, the inclusion of the word Tl10 pnsslve l'esiduol hl!l1t 1'\lmovnl s~stcm shall be deslsned to mH'fOR*DC 34. "/Q11k1/g/11" in the criterion is not necessary when punnlt a1ip1'0prlute perltitllu tlmcllonal testlng to ensure (I) the "s11*1wt11rt1/ /n1egr/1y ls sufficient to describe the stmctuml nnd lellktight Integrity of Its components. (2) tho Section 2.l.4 oflN!JllXT-10-17997, "Medmnistlc Sout'\lo requirement. 1110 allowublc leak rate fol' a given design operability ond pe11bnnance of the system components. und Tem1s White Poper." (Rot: 33) notes that the passive l'llnctor should be lllle of the ncccptm1ce c1*iterill for the test for (3) the operability of the system usu whole and. under cn\'lty cooling system (RCCS) (using either air or water ns *~*t1*11i*t11rt1/ illlel!.l'il)*. In pnrticulllr, for the air-cooled Cllnditll1ns us close to design llS pmcticul, the pe11bmmncc of heat transfur fluid) contributes to the mHTGR sofo1y basis vnrimlt of the RCCS. the system is open and not the foll operational sequence that brings the system into and is subject to component integrity testing. However, lcaktight ut nil. The words "a111l lcakl/.~l11 should be opemtlon, including opemtion ofnssociated systems and Section 6.1 llf INUEXT-11-22708, "Modulllr HTGR Snfoty deleted here and in the ARDC and the SFR versistem mHTOR RCCS nnd the need to verify the abilit)* to transition 11.*" w/111/e 1111d. ifappllmblu, 11m/~1* **011c/i1i1111s as /<it' the RCCS from netlve mode (if present) to pas.~lve mode 111 d<'.*/1111 us pmcl/m/, Ill<! 1'<'1.f111*111mwe *iftllc.fi11/

during post11h1tl'd nccidents. 11pemllm111/ ,\w/11e1wu ... " It appears from the words at the end of the third paragn1ph of the rationale for this el'itcl'ion thnt the NRC stnlTintended tu include the words "/f11pplimh/c" in the cl'itel'lon. but they were inadYertently omitted.

Removal of Text from R11tlon11le Alsu. nt the end of Item (3), the NRC staff has add1.'d wording at the end of the item. relative to the DOE/INL proposed language, l'llgarding "t>fli!rtll/011 t!/'<1pJ'liml>lv por1/1111s qf'tll<! pmtec1/u11.*>Wlt1111 <111</ tllu opeml/1111 '!/'

l/w <1.v.*oc/11ted stmc/111*11/ 11111/ eq11IJ'nWlll m"llng ll'<IM'

• .,iwll'lll." Thcs<l WOl'ds are not inclndcd In either the ARDC or SFR versions of Criterion 37, so the l'llnsons for adding them only to the modulm* HTGR \'ersion of the criterion are not clear. The protection system does not piny a role in operation of the RCCS. Furthermore.

as noted in comments aboYe on modular HTOR DC 34, modular HTGRs, unlike LWRs, SFRs. and possibly other advanced non-LWRs, do not have or need a system that cmrosponds to the Cooling Water System thnt is required by GDC 44. All words nt the end of the criterion that follow "relied 11po11 c/111'/11g postulated cw11id<*11ts" should be deleted.

It appears from the fourth paragraph of the mtionale for this criterion that at one time there wns also reference to "111m*er lmn.yfi:lw," which arc nlso not applicable to QOE/Notjonn! Lqbol'l!loiy Team Comments on Dl'l!ft Regul!J!orv Guidg DG-1330 *Docket ID NRC-20)7-0016: Page 37

Crlte1*lo11 2017 NRC mHTGR*DC Title and Content 2017 NRC Ratlonnles Team Comments operation of the RCCS, which does not rely on eleetrlc lltlWer for Its operation. The fourth pnrngraph ofthe rntitlnnle should nlso be deleted.

JS C'nnl11/11m1*11f llea11w1111v1t/. This criterion is not npplicnblc tu the mHTOR. The mHTOR The conclusion of the NRC stntTthat those criteria are Nut npplicnble to mHTCiR. designs do not hnvc n "pressure rotuinins reactor containment not applicable to the modular HTGR is upprop1*into. This strnctul'Q" but instead 1'llly on a multi-bnn-ier t\mctknml comment also applies to mHTOR-DC 39 through contuimnont contlsurntion to control the releuso of mHTOR-DC 43.

mdlonuclides. Set the mHTOR DC 16 rationale.

44 S11*1M11rol t1111l ~q11/pm~111 *~x1//11g. 111is mHTCJR-DC accounts lbr ud1*tmced ret1cto1* 1ksig11 Coollnll W11te1* Systems In addition to the heat rajection cnpul>ility of the passive system dlfl\lr\"nccs to includ~ coolini.11-equirements for SSCs As uoted in comments on modular HTGR DC 34 and 37, residual het1t removal system. syst11ms to tmnsfer heat tl'tlm lmpOl'lmlt lo sufety, ifnP11lkt1blc: this mHTOR-DC docs not modulur HTORs (unlike LWRs), Sl'Rs. and possibly strt1cturos. systems. and components importum to st1fety to an address thl' t'llslduul heut remol'ul system t'<'qtth.,,'<l undc1* other udvunced n(ln-LWRs, do not huw or need u system ultimate heut sink slmll be. provided, us necessai;\ to trnnsfu1* ARDC34. thnt c.on-esponds to the* Cooling Water System that is thu combined heat load of these strnetures. systems, und t'll\juh'C<I by ODC 44. The DOEJINL comment in this comptl1wn1s under mmnul operntlng und ucddent conditious. The smt'flnscrtt'<l "pussh*e bt1scd on the system deslg1\lbr resard on mHTOR-DC 34 offers n possible tl>q>lunatlon 1'\lslduul hent t'llmovul. lfu speeltk mHTOR design can of why NRC stnt'fseems incon-ectl)* to believe Suituble redundancy in c.ompmwnts nnd lbutures ond suitnblo demonstl'tlle tlmt the reac101* cavity cooling system (RCCS) otherwise. The nddltlon of the words "as 11et"e.~w1ry" to interconneetlm1s lrok detcction, nnd isolation eupnbilitie.~ shnll pi'tlvldes indotlnite core coolin11 capability. then structurnl the criterion is hel1lful, but relative lo the language in the be llrovided to ensure that the system satllty llmction cuu bl! and equipment cooling systems would not be m.'eded. rationale for this cl'ilcrion, every design that is consistent nccomplished. assuming n single tlliluro. with thll detlnition of the modular HTOR contained in TI1e ODC retllrence to lllectrie power wns removed, Refor lo the DOE/INL submittal Is deslsned such that the RCCS the 1'tltlonole for ARDC 17 on elec:trk llower systems. pi'tlvides indetlnite core coollns eapnbility. Cl'iterla 44, 45, and 46 should be marked us "Nol Applimhl~ lo 111~

mt1d11l"r llTGR."

45 lmpe<*tlon 11f'stmet11rol am/ eq11/p111~111 c.v1ollng s,111*1t1111.*. This renamed mHTGR-DC accounts for advanced rt.'llCttlr Cooling Water Systems SameusARDC s~stem design ditfe1'1lnces ttl includo possible coolins As noted In comments on modular HTGR DC 34 und 37, The structurnl and equipment coolins systems shall be t'll\julremcnts for SSCs importunt to safety. modular HTORs (unlike LWRs). SFRs, nnd possibly designed to pennit appropritue periodic inspection ofimp011nnt other advanced non-LWRs. do not have m* need a system components. such us hen\ e.~chnnsers and piplns, to assure the that con-esponds to the Coollns Water System that is Integrity and capability of the systems. requin.><I by ODC 44. The DOE/lNL comment in this regai*d on mHTOR-DC 34 offors a possible explanation of why NRC staff seems incon-ectly to believe otherwise. The addition of the words "as nece.1w<11i' to the criterion is helpful. but relative m the langunge in the rntlonale for this eriterion, every design that is consistent with the detlnltion of the modular HTGR contained in the DOEllNL submittal is designed such that the RCCS provides fodefinite core cooling capability. Criteria 44,

45. und 46 should be murked as "NOi Appllmhle 111 Ille m11d11/111* F/TGR."

POE/Notjonol Lgborntrny Team CmnmWJ!s m1 Draft Regu!ntorv Gujde DG-1330 - Docket ID NRC-2017~0016: Page 38

Crite1*lon 2017 NRC mll'l'GR*DC Title and Content 2017 NRC Rutlon11les Team Comments 46 T~.*lln11 *1fstr1M11ml and c~111/pnwnt *Ylllllng .~1wwms. TI1is renamed ml lTOR*IX' m:counts for advanced reactor Coolln11 Water Systems SumensARDC system design dilTurences to include possible cooling As noted in comments on modular HTOR DC 34 and 37, The structural and equipment ct101ing systems shall be requirements for SSCs Important to safety. Specitic mention modulnr HTORs (unlike l.WRs), SFRs. and possibly desi11ued to pennit approprintc re1*iodlc fi.mctimml testlni; to ofpressuro" testing has been remo,*ed yet remains 11 other ndvanced non*L\VRs. do nut hn\'c orneed 11 system assure (I) the structuml und l~nktlQht lntcgrlt~* of their 11otentlal requirement should it be necessnry us n component that corresponds to the Cooling Wnter System thnt is components, (2) the operablllty and the 1wrfonn11nce of the of" ... nppt'Opriatc periodic fi.mctlonal tcstlnu..." ofcoolins requin.'ll by ODC 44. TI1e DOfl/INL. comment in this system components. and (:I) tho tl11ernblllty ot'the systems us n systems. A non-lctlktlsht syst.-m nmy bo occeptoblo for some rcsord on mHTGR-DC 34 ulTurs o possible c~plntmtion whole nnd. under conditions as close to desi11n us prnctlcul, the desii;ns provided that (I) the system lcakogo docs nnt impact of why NRC staff seems incorrectly to believe pertbrmnnee of the full opemtiom1l Sllqtumccs thnt brinu the sutl:ty functions undo1* ull conditions. and (2) detbnse in otherwise. 1*1w addition of the words "as ne,*es.*my" to systems Into operation for reactor shutdown and postulated depth ls not impactQ\l by S)'stem leakase. the criterion is helpful, but t"elntivo to the lansnage in the accidents. lncludinu opcmtlon ot'ussociatcd s)'stems. mtlonalc for this criterion. ovcry design that is consistent "Active" has been delctt.'ll in item (2) because appropriate with the definition of the modular HTGR contained in opernbllity and perfonnance tests of system components are the DOEllNL submlttol ls dcsisnQ\l such tlmt the RC'CS required res111\lless of their acti\'e or passlni natm"e. The provides indefinite core coollni; capability. Criteria 44.

l.OCA refeNnco hos been 1"emoved to provide fur any 45, and 46 should be marked as "Nil/ Applimh/~ w tlw postulated uccident thut might affect subject SSCs. mtm11/ar 111'Gll.."

The ODC retb1"enee to electric power was 1"emoved. Retb1* to the rationale fur ARDC 17 resnrdins electric power systems.

so Cmlla/1m1en1 design hnsl.~. This criterion is not applicable to the mHTOR. The mHTOR The conclusiou of the NRC stnffthnt these criteria are Not applicnble to mlHOR. desisus do not have a "p1vssure retninins rcnctor containment not applicable to the modular HTOR is npproprlnte. This structure" but Instead rely on a multibo11*ier lltnctlonal comment nlso applies to mHTOR-DC 51 through containment contisumtion to control the t"elensc of mHTGR-DC 57.

radionuclides. Sec the mHTGR-DC 16 rationale.

70 ll.<'1w1t11* m~sel tllld 1-e1wta1* .~1w1a111 s1r11c111m/ design has/~~ New mHTGR design-specific GDC arc neccssury to ensure The wording adopted by the stnfffor these criteria is The dcsisn of the reactor vessel and reactor system shall be that the renctor vessel ond reactor system (lncludins the fuel, corn.>ct nnd consistent with the modular HTOR approach such that their integrity is maintained d11rin1.1 postulated reflector, cm1trol rods, core barrel, and st111ct11rnl supports) to safety deslsn. This comment also applies to mHTGR*

nt.'Cidents (1) to ensure the gcometl)' for passive removol of lntesrlty is preserved for passlw heat removal and for the DC 71 nnd mHTOR-DC 72.

residual heat tl"Om the renctt1r core to the ultimate hcnt sink and Insertion of neutron absorbers.

(2) to permit sufficient lnsertlt111 of the neutron absorbers to provide fllr renc1or shutdown.

J)OE/Nutlonq! LgbQl'l!tory Tcnm Commynts on Draft Rllgulqtory Gulde QG-1330

• Docket ID NRC-20! 7-00! 6: Page 39